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| 5564 | serge | 1 | /* |
| 2 | * Mesa 3-D graphics library |
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| 3 | * |
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| 4 | * Copyright (C) 1999-2007 Brian Paul All Rights Reserved. |
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| 5 | * |
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| 6 | * Permission is hereby granted, free of charge, to any person obtaining a |
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| 7 | * copy of this software and associated documentation files (the "Software"), |
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| 8 | * to deal in the Software without restriction, including without limitation |
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| 9 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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| 10 | * and/or sell copies of the Software, and to permit persons to whom the |
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| 11 | * Software is furnished to do so, subject to the following conditions: |
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| 12 | * |
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| 13 | * The above copyright notice and this permission notice shall be included |
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| 14 | * in all copies or substantial portions of the Software. |
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| 15 | * |
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| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
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| 17 | * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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| 18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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| 19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
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| 20 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
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| 21 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
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| 22 | * OTHER DEALINGS IN THE SOFTWARE. |
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| 23 | */ |
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| 24 | |||
| 25 | /* |
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| 26 | * Triangle Rasterizer Template |
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| 27 | * |
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| 28 | * This file is #include'd to generate custom triangle rasterizers. |
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| 29 | * |
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| 30 | * The following macros may be defined to indicate what auxillary information |
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| 31 | * must be interpolated across the triangle: |
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| 32 | * INTERP_Z - if defined, interpolate integer Z values |
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| 33 | * INTERP_RGB - if defined, interpolate integer RGB values |
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| 34 | * INTERP_ALPHA - if defined, interpolate integer Alpha values |
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| 35 | * INTERP_INT_TEX - if defined, interpolate integer ST texcoords |
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| 36 | * (fast, simple 2-D texture mapping, without |
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| 37 | * perspective correction) |
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| 38 | * INTERP_ATTRIBS - if defined, interpolate arbitrary attribs (texcoords, |
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| 39 | * varying vars, etc) This also causes W to be |
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| 40 | * computed for perspective correction). |
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| 41 | * |
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| 42 | * When one can directly address pixels in the color buffer the following |
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| 43 | * macros can be defined and used to compute pixel addresses during |
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| 44 | * rasterization (see pRow): |
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| 45 | * PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint) |
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| 46 | * BYTES_PER_ROW - number of bytes per row in the color buffer |
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| 47 | * PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where |
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| 48 | * Y==0 at bottom of screen and increases upward. |
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| 49 | * |
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| 50 | * Similarly, for direct depth buffer access, this type is used for depth |
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| 51 | * buffer addressing (see zRow): |
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| 52 | * DEPTH_TYPE - either GLushort or GLuint |
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| 53 | * |
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| 54 | * Optionally, one may provide one-time setup code per triangle: |
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| 55 | * SETUP_CODE - code which is to be executed once per triangle |
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| 56 | * |
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| 57 | * The following macro MUST be defined: |
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| 58 | * RENDER_SPAN(span) - code to write a span of pixels. |
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| 59 | * |
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| 60 | * This code was designed for the origin to be in the lower-left corner. |
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| 61 | * |
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| 62 | * Inspired by triangle rasterizer code written by Allen Akin. Thanks Allen! |
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| 63 | * |
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| 64 | * |
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| 65 | * Some notes on rasterization accuracy: |
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| 66 | * |
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| 67 | * This code uses fixed point arithmetic (the GLfixed type) to iterate |
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| 68 | * over the triangle edges and interpolate ancillary data (such as Z, |
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| 69 | * color, secondary color, etc). The number of fractional bits in |
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| 70 | * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the |
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| 71 | * accuracy of rasterization. |
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| 72 | * |
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| 73 | * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest |
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| 74 | * 1/16 of a pixel. If we're walking up a long, nearly vertical edge |
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| 75 | * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in |
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| 76 | * GLfixed to walk the edge without error. If the maximum viewport |
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| 77 | * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits. |
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| 78 | * |
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| 79 | * Historically, Mesa has used 11 fractional bits in GLfixed, snaps |
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| 80 | * vertices to 1/16 pixel and allowed a maximum viewport height of 2K |
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| 81 | * pixels. 11 fractional bits is actually insufficient for accurately |
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| 82 | * rasterizing some triangles. More recently, the maximum viewport |
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| 83 | * height was increased to 4K pixels. Thus, Mesa should be using 16 |
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| 84 | * fractional bits in GLfixed. Unfortunately, there may be some issues |
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| 85 | * with setting FIXED_FRAC_BITS=16, such as multiplication overflow. |
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| 86 | * This will have to be examined in some detail... |
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| 87 | * |
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| 88 | * For now, if you find rasterization errors, particularly with tall, |
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| 89 | * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing |
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| 90 | * SUB_PIXEL_BITS. |
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| 91 | */ |
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| 92 | |||
| 93 | |||
| 94 | #ifndef MAX_GLUINT |
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| 95 | #define MAX_GLUINT 0xffffffffu |
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| 96 | #endif |
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| 97 | |||
| 98 | |||
| 99 | /* |
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| 100 | * Some code we unfortunately need to prevent negative interpolated colors. |
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| 101 | */ |
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| 102 | #ifndef CLAMP_INTERPOLANT |
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| 103 | #define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN) \ |
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| 104 | do { \ |
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| 105 | GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP; \ |
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| 106 | if (endVal < 0) { \ |
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| 107 | span.CHANNEL -= endVal; \ |
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| 108 | } \ |
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| 109 | if (span.CHANNEL < 0) { \ |
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| 110 | span.CHANNEL = 0; \ |
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| 111 | } \ |
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| 112 | } while (0) |
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| 113 | #endif |
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| 114 | |||
| 115 | |||
| 116 | static void NAME(struct gl_context *ctx, const SWvertex *v0, |
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| 117 | const SWvertex *v1, |
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| 118 | const SWvertex *v2 ) |
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| 119 | { |
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| 120 | typedef struct { |
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| 121 | const SWvertex *v0, *v1; /* Y(v0) < Y(v1) */ |
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| 122 | GLfloat dx; /* X(v1) - X(v0) */ |
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| 123 | GLfloat dy; /* Y(v1) - Y(v0) */ |
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| 124 | GLfloat dxdy; /* dx/dy */ |
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| 125 | GLfixed fdxdy; /* dx/dy in fixed-point */ |
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| 126 | GLfloat adjy; /* adjust from v[0]->fy to fsy, scaled */ |
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| 127 | GLfixed fsx; /* first sample point x coord */ |
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| 128 | GLfixed fsy; |
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| 129 | GLfixed fx0; /* fixed pt X of lower endpoint */ |
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| 130 | GLint lines; /* number of lines to be sampled on this edge */ |
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| 131 | } EdgeT; |
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| 132 | |||
| 133 | const SWcontext *swrast = SWRAST_CONTEXT(ctx); |
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| 134 | #ifdef INTERP_Z |
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| 135 | const GLint depthBits = ctx->DrawBuffer->Visual.depthBits; |
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| 136 | const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0; |
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| 137 | const GLfloat maxDepth = ctx->DrawBuffer->_DepthMaxF; |
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| 138 | #define FixedToDepth(F) ((F) >> fixedToDepthShift) |
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| 139 | #endif |
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| 140 | EdgeT eMaj, eTop, eBot; |
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| 141 | GLfloat oneOverArea; |
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| 142 | const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */ |
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| 143 | GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign; |
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| 144 | const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */ |
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| 145 | GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy; |
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| 146 | |||
| 147 | SWspan span; |
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| 148 | |||
| 149 | (void) swrast; |
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| 150 | |||
| 151 | INIT_SPAN(span, GL_POLYGON); |
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| 152 | span.y = 0; /* silence warnings */ |
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| 153 | |||
| 154 | #ifdef INTERP_Z |
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| 155 | (void) fixedToDepthShift; |
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| 156 | #endif |
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| 157 | |||
| 158 | /* |
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| 159 | printf("%s()\n", __func__); |
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| 160 | printf(" %g, %g, %g\n", |
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| 161 | v0->attrib[VARYING_SLOT_POS][0], |
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| 162 | v0->attrib[VARYING_SLOT_POS][1], |
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| 163 | v0->attrib[VARYING_SLOT_POS][2]); |
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| 164 | printf(" %g, %g, %g\n", |
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| 165 | v1->attrib[VARYING_SLOT_POS][0], |
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| 166 | v1->attrib[VARYING_SLOT_POS][1], |
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| 167 | v1->attrib[VARYING_SLOT_POS][2]); |
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| 168 | printf(" %g, %g, %g\n", |
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| 169 | v2->attrib[VARYING_SLOT_POS][0], |
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| 170 | v2->attrib[VARYING_SLOT_POS][1], |
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| 171 | v2->attrib[VARYING_SLOT_POS][2]); |
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| 172 | */ |
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| 173 | |||
| 174 | /* Compute fixed point x,y coords w/ half-pixel offsets and snapping. |
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| 175 | * And find the order of the 3 vertices along the Y axis. |
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| 176 | */ |
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| 177 | { |
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| 178 | const GLfixed fy0 = FloatToFixed(v0->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; |
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| 179 | const GLfixed fy1 = FloatToFixed(v1->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; |
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| 180 | const GLfixed fy2 = FloatToFixed(v2->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; |
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| 181 | if (fy0 <= fy1) { |
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| 182 | if (fy1 <= fy2) { |
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| 183 | /* y0 <= y1 <= y2 */ |
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| 184 | vMin = v0; vMid = v1; vMax = v2; |
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| 185 | vMin_fy = fy0; vMid_fy = fy1; vMax_fy = fy2; |
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| 186 | } |
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| 187 | else if (fy2 <= fy0) { |
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| 188 | /* y2 <= y0 <= y1 */ |
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| 189 | vMin = v2; vMid = v0; vMax = v1; |
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| 190 | vMin_fy = fy2; vMid_fy = fy0; vMax_fy = fy1; |
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| 191 | } |
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| 192 | else { |
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| 193 | /* y0 <= y2 <= y1 */ |
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| 194 | vMin = v0; vMid = v2; vMax = v1; |
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| 195 | vMin_fy = fy0; vMid_fy = fy2; vMax_fy = fy1; |
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| 196 | bf = -bf; |
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| 197 | } |
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| 198 | } |
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| 199 | else { |
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| 200 | if (fy0 <= fy2) { |
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| 201 | /* y1 <= y0 <= y2 */ |
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| 202 | vMin = v1; vMid = v0; vMax = v2; |
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| 203 | vMin_fy = fy1; vMid_fy = fy0; vMax_fy = fy2; |
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| 204 | bf = -bf; |
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| 205 | } |
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| 206 | else if (fy2 <= fy1) { |
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| 207 | /* y2 <= y1 <= y0 */ |
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| 208 | vMin = v2; vMid = v1; vMax = v0; |
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| 209 | vMin_fy = fy2; vMid_fy = fy1; vMax_fy = fy0; |
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| 210 | bf = -bf; |
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| 211 | } |
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| 212 | else { |
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| 213 | /* y1 <= y2 <= y0 */ |
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| 214 | vMin = v1; vMid = v2; vMax = v0; |
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| 215 | vMin_fy = fy1; vMid_fy = fy2; vMax_fy = fy0; |
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| 216 | } |
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| 217 | } |
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| 218 | |||
| 219 | /* fixed point X coords */ |
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| 220 | vMin_fx = FloatToFixed(vMin->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; |
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| 221 | vMid_fx = FloatToFixed(vMid->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; |
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| 222 | vMax_fx = FloatToFixed(vMax->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; |
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| 223 | } |
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| 224 | |||
| 225 | /* vertex/edge relationship */ |
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| 226 | eMaj.v0 = vMin; eMaj.v1 = vMax; /*TODO: .v1's not needed */ |
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| 227 | eTop.v0 = vMid; eTop.v1 = vMax; |
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| 228 | eBot.v0 = vMin; eBot.v1 = vMid; |
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| 229 | |||
| 230 | /* compute deltas for each edge: vertex[upper] - vertex[lower] */ |
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| 231 | eMaj.dx = FixedToFloat(vMax_fx - vMin_fx); |
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| 232 | eMaj.dy = FixedToFloat(vMax_fy - vMin_fy); |
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| 233 | eTop.dx = FixedToFloat(vMax_fx - vMid_fx); |
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| 234 | eTop.dy = FixedToFloat(vMax_fy - vMid_fy); |
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| 235 | eBot.dx = FixedToFloat(vMid_fx - vMin_fx); |
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| 236 | eBot.dy = FixedToFloat(vMid_fy - vMin_fy); |
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| 237 | |||
| 238 | /* compute area, oneOverArea and perform backface culling */ |
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| 239 | { |
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| 240 | const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy; |
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| 241 | |||
| 242 | if (IS_INF_OR_NAN(area) || area == 0.0F) |
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| 243 | return; |
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| 244 | |||
| 245 | if (area * bf * swrast->_BackfaceCullSign < 0.0) |
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| 246 | return; |
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| 247 | |||
| 248 | oneOverArea = 1.0F / area; |
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| 249 | |||
| 250 | /* 0 = front, 1 = back */ |
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| 251 | span.facing = oneOverArea * bf > 0.0F; |
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| 252 | } |
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| 253 | |||
| 254 | /* Edge setup. For a triangle strip these could be reused... */ |
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| 255 | { |
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| 256 | eMaj.fsy = FixedCeil(vMin_fy); |
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| 257 | eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy)); |
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| 258 | if (eMaj.lines > 0) { |
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| 259 | eMaj.dxdy = eMaj.dx / eMaj.dy; |
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| 260 | eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy); |
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| 261 | eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */ |
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| 262 | eMaj.fx0 = vMin_fx; |
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| 263 | eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy); |
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| 264 | } |
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| 265 | else { |
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| 266 | return; /*CULLED*/ |
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| 267 | } |
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| 268 | |||
| 269 | eTop.fsy = FixedCeil(vMid_fy); |
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| 270 | eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy)); |
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| 271 | if (eTop.lines > 0) { |
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| 272 | eTop.dxdy = eTop.dx / eTop.dy; |
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| 273 | eTop.fdxdy = SignedFloatToFixed(eTop.dxdy); |
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| 274 | eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */ |
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| 275 | eTop.fx0 = vMid_fx; |
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| 276 | eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy); |
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| 277 | } |
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| 278 | |||
| 279 | eBot.fsy = FixedCeil(vMin_fy); |
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| 280 | eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy)); |
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| 281 | if (eBot.lines > 0) { |
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| 282 | eBot.dxdy = eBot.dx / eBot.dy; |
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| 283 | eBot.fdxdy = SignedFloatToFixed(eBot.dxdy); |
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| 284 | eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */ |
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| 285 | eBot.fx0 = vMin_fx; |
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| 286 | eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy); |
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| 287 | } |
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| 288 | } |
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| 289 | |||
| 290 | /* |
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| 291 | * Conceptually, we view a triangle as two subtriangles |
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| 292 | * separated by a perfectly horizontal line. The edge that is |
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| 293 | * intersected by this line is one with maximal absolute dy; we |
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| 294 | * call it a ``major'' edge. The other two edges are the |
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| 295 | * ``top'' edge (for the upper subtriangle) and the ``bottom'' |
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| 296 | * edge (for the lower subtriangle). If either of these two |
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| 297 | * edges is horizontal or very close to horizontal, the |
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| 298 | * corresponding subtriangle might cover zero sample points; |
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| 299 | * we take care to handle such cases, for performance as well |
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| 300 | * as correctness. |
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| 301 | * |
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| 302 | * By stepping rasterization parameters along the major edge, |
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| 303 | * we can avoid recomputing them at the discontinuity where |
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| 304 | * the top and bottom edges meet. However, this forces us to |
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| 305 | * be able to scan both left-to-right and right-to-left. |
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| 306 | * Also, we must determine whether the major edge is at the |
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| 307 | * left or right side of the triangle. We do this by |
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| 308 | * computing the magnitude of the cross-product of the major |
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| 309 | * and top edges. Since this magnitude depends on the sine of |
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| 310 | * the angle between the two edges, its sign tells us whether |
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| 311 | * we turn to the left or to the right when travelling along |
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| 312 | * the major edge to the top edge, and from this we infer |
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| 313 | * whether the major edge is on the left or the right. |
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| 314 | * |
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| 315 | * Serendipitously, this cross-product magnitude is also a |
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| 316 | * value we need to compute the iteration parameter |
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| 317 | * derivatives for the triangle, and it can be used to perform |
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| 318 | * backface culling because its sign tells us whether the |
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| 319 | * triangle is clockwise or counterclockwise. In this code we |
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| 320 | * refer to it as ``area'' because it's also proportional to |
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| 321 | * the pixel area of the triangle. |
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| 322 | */ |
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| 323 | |||
| 324 | { |
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| 325 | GLint scan_from_left_to_right; /* true if scanning left-to-right */ |
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| 326 | |||
| 327 | /* |
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| 328 | * Execute user-supplied setup code |
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| 329 | */ |
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| 330 | #ifdef SETUP_CODE |
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| 331 | SETUP_CODE |
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| 332 | #endif |
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| 333 | |||
| 334 | scan_from_left_to_right = (oneOverArea < 0.0F); |
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| 335 | |||
| 336 | |||
| 337 | /* compute d?/dx and d?/dy derivatives */ |
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| 338 | #ifdef INTERP_Z |
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| 339 | span.interpMask |= SPAN_Z; |
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| 340 | { |
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| 341 | GLfloat eMaj_dz = vMax->attrib[VARYING_SLOT_POS][2] - vMin->attrib[VARYING_SLOT_POS][2]; |
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| 342 | GLfloat eBot_dz = vMid->attrib[VARYING_SLOT_POS][2] - vMin->attrib[VARYING_SLOT_POS][2]; |
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| 343 | span.attrStepX[VARYING_SLOT_POS][2] = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz); |
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| 344 | if (span.attrStepX[VARYING_SLOT_POS][2] > maxDepth || |
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| 345 | span.attrStepX[VARYING_SLOT_POS][2] < -maxDepth) { |
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| 346 | /* probably a sliver triangle */ |
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| 347 | span.attrStepX[VARYING_SLOT_POS][2] = 0.0; |
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| 348 | span.attrStepY[VARYING_SLOT_POS][2] = 0.0; |
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| 349 | } |
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| 350 | else { |
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| 351 | span.attrStepY[VARYING_SLOT_POS][2] = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx); |
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| 352 | } |
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| 353 | if (depthBits <= 16) |
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| 354 | span.zStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_POS][2]); |
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| 355 | else |
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| 356 | span.zStep = (GLint) span.attrStepX[VARYING_SLOT_POS][2]; |
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| 357 | } |
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| 358 | #endif |
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| 359 | #ifdef INTERP_RGB |
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| 360 | span.interpMask |= SPAN_RGBA; |
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| 361 | if (ctx->Light.ShadeModel == GL_SMOOTH) { |
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| 362 | GLfloat eMaj_dr = (GLfloat) (vMax->color[RCOMP] - vMin->color[RCOMP]); |
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| 363 | GLfloat eBot_dr = (GLfloat) (vMid->color[RCOMP] - vMin->color[RCOMP]); |
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| 364 | GLfloat eMaj_dg = (GLfloat) (vMax->color[GCOMP] - vMin->color[GCOMP]); |
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| 365 | GLfloat eBot_dg = (GLfloat) (vMid->color[GCOMP] - vMin->color[GCOMP]); |
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| 366 | GLfloat eMaj_db = (GLfloat) (vMax->color[BCOMP] - vMin->color[BCOMP]); |
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| 367 | GLfloat eBot_db = (GLfloat) (vMid->color[BCOMP] - vMin->color[BCOMP]); |
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| 368 | # ifdef INTERP_ALPHA |
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| 369 | GLfloat eMaj_da = (GLfloat) (vMax->color[ACOMP] - vMin->color[ACOMP]); |
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| 370 | GLfloat eBot_da = (GLfloat) (vMid->color[ACOMP] - vMin->color[ACOMP]); |
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| 371 | # endif |
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| 372 | span.attrStepX[VARYING_SLOT_COL0][0] = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr); |
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| 373 | span.attrStepY[VARYING_SLOT_COL0][0] = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx); |
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| 374 | span.attrStepX[VARYING_SLOT_COL0][1] = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg); |
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| 375 | span.attrStepY[VARYING_SLOT_COL0][1] = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx); |
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| 376 | span.attrStepX[VARYING_SLOT_COL0][2] = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db); |
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| 377 | span.attrStepY[VARYING_SLOT_COL0][2] = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx); |
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| 378 | span.redStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][0]); |
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| 379 | span.greenStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][1]); |
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| 380 | span.blueStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][2]); |
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| 381 | # ifdef INTERP_ALPHA |
||
| 382 | span.attrStepX[VARYING_SLOT_COL0][3] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da); |
||
| 383 | span.attrStepY[VARYING_SLOT_COL0][3] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx); |
||
| 384 | span.alphaStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][3]); |
||
| 385 | # endif /* INTERP_ALPHA */ |
||
| 386 | } |
||
| 387 | else { |
||
| 388 | assert(ctx->Light.ShadeModel == GL_FLAT); |
||
| 389 | span.interpMask |= SPAN_FLAT; |
||
| 390 | span.attrStepX[VARYING_SLOT_COL0][0] = span.attrStepY[VARYING_SLOT_COL0][0] = 0.0F; |
||
| 391 | span.attrStepX[VARYING_SLOT_COL0][1] = span.attrStepY[VARYING_SLOT_COL0][1] = 0.0F; |
||
| 392 | span.attrStepX[VARYING_SLOT_COL0][2] = span.attrStepY[VARYING_SLOT_COL0][2] = 0.0F; |
||
| 393 | span.redStep = 0; |
||
| 394 | span.greenStep = 0; |
||
| 395 | span.blueStep = 0; |
||
| 396 | # ifdef INTERP_ALPHA |
||
| 397 | span.attrStepX[VARYING_SLOT_COL0][3] = span.attrStepY[VARYING_SLOT_COL0][3] = 0.0F; |
||
| 398 | span.alphaStep = 0; |
||
| 399 | # endif |
||
| 400 | } |
||
| 401 | #endif /* INTERP_RGB */ |
||
| 402 | #ifdef INTERP_INT_TEX |
||
| 403 | { |
||
| 404 | GLfloat eMaj_ds = (vMax->attrib[VARYING_SLOT_TEX0][0] - vMin->attrib[VARYING_SLOT_TEX0][0]) * S_SCALE; |
||
| 405 | GLfloat eBot_ds = (vMid->attrib[VARYING_SLOT_TEX0][0] - vMin->attrib[VARYING_SLOT_TEX0][0]) * S_SCALE; |
||
| 406 | GLfloat eMaj_dt = (vMax->attrib[VARYING_SLOT_TEX0][1] - vMin->attrib[VARYING_SLOT_TEX0][1]) * T_SCALE; |
||
| 407 | GLfloat eBot_dt = (vMid->attrib[VARYING_SLOT_TEX0][1] - vMin->attrib[VARYING_SLOT_TEX0][1]) * T_SCALE; |
||
| 408 | span.attrStepX[VARYING_SLOT_TEX0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds); |
||
| 409 | span.attrStepY[VARYING_SLOT_TEX0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx); |
||
| 410 | span.attrStepX[VARYING_SLOT_TEX0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt); |
||
| 411 | span.attrStepY[VARYING_SLOT_TEX0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx); |
||
| 412 | span.intTexStep[0] = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_TEX0][0]); |
||
| 413 | span.intTexStep[1] = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_TEX0][1]); |
||
| 414 | } |
||
| 415 | #endif |
||
| 416 | #ifdef INTERP_ATTRIBS |
||
| 417 | { |
||
| 418 | /* attrib[VARYING_SLOT_POS][3] is 1/W */ |
||
| 419 | const GLfloat wMax = vMax->attrib[VARYING_SLOT_POS][3]; |
||
| 420 | const GLfloat wMin = vMin->attrib[VARYING_SLOT_POS][3]; |
||
| 421 | const GLfloat wMid = vMid->attrib[VARYING_SLOT_POS][3]; |
||
| 422 | { |
||
| 423 | const GLfloat eMaj_dw = wMax - wMin; |
||
| 424 | const GLfloat eBot_dw = wMid - wMin; |
||
| 425 | span.attrStepX[VARYING_SLOT_POS][3] = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw); |
||
| 426 | span.attrStepY[VARYING_SLOT_POS][3] = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx); |
||
| 427 | } |
||
| 428 | ATTRIB_LOOP_BEGIN |
||
| 429 | if (swrast->_InterpMode[attr] == GL_FLAT) { |
||
| 430 | ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0); |
||
| 431 | ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0); |
||
| 432 | } |
||
| 433 | else { |
||
| 434 | GLuint c; |
||
| 435 | for (c = 0; c < 4; c++) { |
||
| 436 | GLfloat eMaj_da = vMax->attrib[attr][c] * wMax - vMin->attrib[attr][c] * wMin; |
||
| 437 | GLfloat eBot_da = vMid->attrib[attr][c] * wMid - vMin->attrib[attr][c] * wMin; |
||
| 438 | span.attrStepX[attr][c] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da); |
||
| 439 | span.attrStepY[attr][c] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx); |
||
| 440 | } |
||
| 441 | } |
||
| 442 | ATTRIB_LOOP_END |
||
| 443 | } |
||
| 444 | #endif |
||
| 445 | |||
| 446 | /* |
||
| 447 | * We always sample at pixel centers. However, we avoid |
||
| 448 | * explicit half-pixel offsets in this code by incorporating |
||
| 449 | * the proper offset in each of x and y during the |
||
| 450 | * transformation to window coordinates. |
||
| 451 | * |
||
| 452 | * We also apply the usual rasterization rules to prevent |
||
| 453 | * cracks and overlaps. A pixel is considered inside a |
||
| 454 | * subtriangle if it meets all of four conditions: it is on or |
||
| 455 | * to the right of the left edge, strictly to the left of the |
||
| 456 | * right edge, on or below the top edge, and strictly above |
||
| 457 | * the bottom edge. (Some edges may be degenerate.) |
||
| 458 | * |
||
| 459 | * The following discussion assumes left-to-right scanning |
||
| 460 | * (that is, the major edge is on the left); the right-to-left |
||
| 461 | * case is a straightforward variation. |
||
| 462 | * |
||
| 463 | * We start by finding the half-integral y coordinate that is |
||
| 464 | * at or below the top of the triangle. This gives us the |
||
| 465 | * first scan line that could possibly contain pixels that are |
||
| 466 | * inside the triangle. |
||
| 467 | * |
||
| 468 | * Next we creep down the major edge until we reach that y, |
||
| 469 | * and compute the corresponding x coordinate on the edge. |
||
| 470 | * Then we find the half-integral x that lies on or just |
||
| 471 | * inside the edge. This is the first pixel that might lie in |
||
| 472 | * the interior of the triangle. (We won't know for sure |
||
| 473 | * until we check the other edges.) |
||
| 474 | * |
||
| 475 | * As we rasterize the triangle, we'll step down the major |
||
| 476 | * edge. For each step in y, we'll move an integer number |
||
| 477 | * of steps in x. There are two possible x step sizes, which |
||
| 478 | * we'll call the ``inner'' step (guaranteed to land on the |
||
| 479 | * edge or inside it) and the ``outer'' step (guaranteed to |
||
| 480 | * land on the edge or outside it). The inner and outer steps |
||
| 481 | * differ by one. During rasterization we maintain an error |
||
| 482 | * term that indicates our distance from the true edge, and |
||
| 483 | * select either the inner step or the outer step, whichever |
||
| 484 | * gets us to the first pixel that falls inside the triangle. |
||
| 485 | * |
||
| 486 | * All parameters (z, red, etc.) as well as the buffer |
||
| 487 | * addresses for color and z have inner and outer step values, |
||
| 488 | * so that we can increment them appropriately. This method |
||
| 489 | * eliminates the need to adjust parameters by creeping a |
||
| 490 | * sub-pixel amount into the triangle at each scanline. |
||
| 491 | */ |
||
| 492 | |||
| 493 | { |
||
| 494 | GLint subTriangle; |
||
| 495 | GLfixed fxLeftEdge = 0, fxRightEdge = 0; |
||
| 496 | GLfixed fdxLeftEdge = 0, fdxRightEdge = 0; |
||
| 497 | GLfixed fError = 0, fdError = 0; |
||
| 498 | #ifdef PIXEL_ADDRESS |
||
| 499 | PIXEL_TYPE *pRow = NULL; |
||
| 500 | GLint dPRowOuter = 0, dPRowInner; /* offset in bytes */ |
||
| 501 | #endif |
||
| 502 | #ifdef INTERP_Z |
||
| 503 | # ifdef DEPTH_TYPE |
||
| 504 | struct gl_renderbuffer *zrb |
||
| 505 | = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer; |
||
| 506 | DEPTH_TYPE *zRow = NULL; |
||
| 507 | GLint dZRowOuter = 0, dZRowInner; /* offset in bytes */ |
||
| 508 | # endif |
||
| 509 | GLuint zLeft = 0; |
||
| 510 | GLfixed fdzOuter = 0, fdzInner; |
||
| 511 | #endif |
||
| 512 | #ifdef INTERP_RGB |
||
| 513 | GLint rLeft = 0, fdrOuter = 0, fdrInner; |
||
| 514 | GLint gLeft = 0, fdgOuter = 0, fdgInner; |
||
| 515 | GLint bLeft = 0, fdbOuter = 0, fdbInner; |
||
| 516 | #endif |
||
| 517 | #ifdef INTERP_ALPHA |
||
| 518 | GLint aLeft = 0, fdaOuter = 0, fdaInner; |
||
| 519 | #endif |
||
| 520 | #ifdef INTERP_INT_TEX |
||
| 521 | GLfixed sLeft=0, dsOuter=0, dsInner; |
||
| 522 | GLfixed tLeft=0, dtOuter=0, dtInner; |
||
| 523 | #endif |
||
| 524 | #ifdef INTERP_ATTRIBS |
||
| 525 | GLfloat wLeft = 0, dwOuter = 0, dwInner; |
||
| 526 | GLfloat attrLeft[VARYING_SLOT_MAX][4]; |
||
| 527 | GLfloat daOuter[VARYING_SLOT_MAX][4], daInner[VARYING_SLOT_MAX][4]; |
||
| 528 | #endif |
||
| 529 | |||
| 530 | for (subTriangle=0; subTriangle<=1; subTriangle++) { |
||
| 531 | EdgeT *eLeft, *eRight; |
||
| 532 | int setupLeft, setupRight; |
||
| 533 | int lines; |
||
| 534 | |||
| 535 | if (subTriangle==0) { |
||
| 536 | /* bottom half */ |
||
| 537 | if (scan_from_left_to_right) { |
||
| 538 | eLeft = &eMaj; |
||
| 539 | eRight = &eBot; |
||
| 540 | lines = eRight->lines; |
||
| 541 | setupLeft = 1; |
||
| 542 | setupRight = 1; |
||
| 543 | } |
||
| 544 | else { |
||
| 545 | eLeft = &eBot; |
||
| 546 | eRight = &eMaj; |
||
| 547 | lines = eLeft->lines; |
||
| 548 | setupLeft = 1; |
||
| 549 | setupRight = 1; |
||
| 550 | } |
||
| 551 | } |
||
| 552 | else { |
||
| 553 | /* top half */ |
||
| 554 | if (scan_from_left_to_right) { |
||
| 555 | eLeft = &eMaj; |
||
| 556 | eRight = &eTop; |
||
| 557 | lines = eRight->lines; |
||
| 558 | setupLeft = 0; |
||
| 559 | setupRight = 1; |
||
| 560 | } |
||
| 561 | else { |
||
| 562 | eLeft = &eTop; |
||
| 563 | eRight = &eMaj; |
||
| 564 | lines = eLeft->lines; |
||
| 565 | setupLeft = 1; |
||
| 566 | setupRight = 0; |
||
| 567 | } |
||
| 568 | if (lines == 0) |
||
| 569 | return; |
||
| 570 | } |
||
| 571 | |||
| 572 | if (setupLeft && eLeft->lines > 0) { |
||
| 573 | const SWvertex *vLower = eLeft->v0; |
||
| 574 | const GLfixed fsy = eLeft->fsy; |
||
| 575 | const GLfixed fsx = eLeft->fsx; /* no fractional part */ |
||
| 576 | const GLfixed fx = FixedCeil(fsx); /* no fractional part */ |
||
| 577 | const GLfixed adjx = (GLfixed) (fx - eLeft->fx0); /* SCALED! */ |
||
| 578 | const GLfixed adjy = (GLfixed) eLeft->adjy; /* SCALED! */ |
||
| 579 | GLint idxOuter; |
||
| 580 | GLfloat dxOuter; |
||
| 581 | GLfixed fdxOuter; |
||
| 582 | |||
| 583 | fError = fx - fsx - FIXED_ONE; |
||
| 584 | fxLeftEdge = fsx - FIXED_EPSILON; |
||
| 585 | fdxLeftEdge = eLeft->fdxdy; |
||
| 586 | fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON); |
||
| 587 | fdError = fdxOuter - fdxLeftEdge + FIXED_ONE; |
||
| 588 | idxOuter = FixedToInt(fdxOuter); |
||
| 589 | dxOuter = (GLfloat) idxOuter; |
||
| 590 | span.y = FixedToInt(fsy); |
||
| 591 | |||
| 592 | /* silence warnings on some compilers */ |
||
| 593 | (void) dxOuter; |
||
| 594 | (void) adjx; |
||
| 595 | (void) adjy; |
||
| 596 | (void) vLower; |
||
| 597 | |||
| 598 | #ifdef PIXEL_ADDRESS |
||
| 599 | { |
||
| 600 | pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(FixedToInt(fxLeftEdge), span.y); |
||
| 601 | dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE); |
||
| 602 | /* negative because Y=0 at bottom and increases upward */ |
||
| 603 | } |
||
| 604 | #endif |
||
| 605 | /* |
||
| 606 | * Now we need the set of parameter (z, color, etc.) values at |
||
| 607 | * the point (fx, fsy). This gives us properly-sampled parameter |
||
| 608 | * values that we can step from pixel to pixel. Furthermore, |
||
| 609 | * although we might have intermediate results that overflow |
||
| 610 | * the normal parameter range when we step temporarily outside |
||
| 611 | * the triangle, we shouldn't overflow or underflow for any |
||
| 612 | * pixel that's actually inside the triangle. |
||
| 613 | */ |
||
| 614 | |||
| 615 | #ifdef INTERP_Z |
||
| 616 | { |
||
| 617 | GLfloat z0 = vLower->attrib[VARYING_SLOT_POS][2]; |
||
| 618 | if (depthBits <= 16) { |
||
| 619 | /* interpolate fixed-pt values */ |
||
| 620 | GLfloat tmp = (z0 * FIXED_SCALE |
||
| 621 | + span.attrStepX[VARYING_SLOT_POS][2] * adjx |
||
| 622 | + span.attrStepY[VARYING_SLOT_POS][2] * adjy) + FIXED_HALF; |
||
| 623 | if (tmp < MAX_GLUINT / 2) |
||
| 624 | zLeft = (GLfixed) tmp; |
||
| 625 | else |
||
| 626 | zLeft = MAX_GLUINT / 2; |
||
| 627 | fdzOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_POS][2] + |
||
| 628 | dxOuter * span.attrStepX[VARYING_SLOT_POS][2]); |
||
| 629 | } |
||
| 630 | else { |
||
| 631 | /* interpolate depth values w/out scaling */ |
||
| 632 | zLeft = (GLuint) (z0 + span.attrStepX[VARYING_SLOT_POS][2] * FixedToFloat(adjx) |
||
| 633 | + span.attrStepY[VARYING_SLOT_POS][2] * FixedToFloat(adjy)); |
||
| 634 | fdzOuter = (GLint) (span.attrStepY[VARYING_SLOT_POS][2] + |
||
| 635 | dxOuter * span.attrStepX[VARYING_SLOT_POS][2]); |
||
| 636 | } |
||
| 637 | # ifdef DEPTH_TYPE |
||
| 638 | zRow = (DEPTH_TYPE *) |
||
| 639 | _swrast_pixel_address(zrb, FixedToInt(fxLeftEdge), span.y); |
||
| 640 | dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE); |
||
| 641 | # endif |
||
| 642 | } |
||
| 643 | #endif |
||
| 644 | #ifdef INTERP_RGB |
||
| 645 | if (ctx->Light.ShadeModel == GL_SMOOTH) { |
||
| 646 | rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP]) |
||
| 647 | + span.attrStepX[VARYING_SLOT_COL0][0] * adjx |
||
| 648 | + span.attrStepY[VARYING_SLOT_COL0][0] * adjy) + FIXED_HALF; |
||
| 649 | gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP]) |
||
| 650 | + span.attrStepX[VARYING_SLOT_COL0][1] * adjx |
||
| 651 | + span.attrStepY[VARYING_SLOT_COL0][1] * adjy) + FIXED_HALF; |
||
| 652 | bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP]) |
||
| 653 | + span.attrStepX[VARYING_SLOT_COL0][2] * adjx |
||
| 654 | + span.attrStepY[VARYING_SLOT_COL0][2] * adjy) + FIXED_HALF; |
||
| 655 | fdrOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][0] |
||
| 656 | + dxOuter * span.attrStepX[VARYING_SLOT_COL0][0]); |
||
| 657 | fdgOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][1] |
||
| 658 | + dxOuter * span.attrStepX[VARYING_SLOT_COL0][1]); |
||
| 659 | fdbOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][2] |
||
| 660 | + dxOuter * span.attrStepX[VARYING_SLOT_COL0][2]); |
||
| 661 | # ifdef INTERP_ALPHA |
||
| 662 | aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP]) |
||
| 663 | + span.attrStepX[VARYING_SLOT_COL0][3] * adjx |
||
| 664 | + span.attrStepY[VARYING_SLOT_COL0][3] * adjy) + FIXED_HALF; |
||
| 665 | fdaOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][3] |
||
| 666 | + dxOuter * span.attrStepX[VARYING_SLOT_COL0][3]); |
||
| 667 | # endif |
||
| 668 | } |
||
| 669 | else { |
||
| 670 | assert(ctx->Light.ShadeModel == GL_FLAT); |
||
| 671 | rLeft = ChanToFixed(v2->color[RCOMP]); |
||
| 672 | gLeft = ChanToFixed(v2->color[GCOMP]); |
||
| 673 | bLeft = ChanToFixed(v2->color[BCOMP]); |
||
| 674 | fdrOuter = fdgOuter = fdbOuter = 0; |
||
| 675 | # ifdef INTERP_ALPHA |
||
| 676 | aLeft = ChanToFixed(v2->color[ACOMP]); |
||
| 677 | fdaOuter = 0; |
||
| 678 | # endif |
||
| 679 | } |
||
| 680 | #endif /* INTERP_RGB */ |
||
| 681 | |||
| 682 | |||
| 683 | #ifdef INTERP_INT_TEX |
||
| 684 | { |
||
| 685 | GLfloat s0, t0; |
||
| 686 | s0 = vLower->attrib[VARYING_SLOT_TEX0][0] * S_SCALE; |
||
| 687 | sLeft = (GLfixed)(s0 * FIXED_SCALE + span.attrStepX[VARYING_SLOT_TEX0][0] * adjx |
||
| 688 | + span.attrStepY[VARYING_SLOT_TEX0][0] * adjy) + FIXED_HALF; |
||
| 689 | dsOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_TEX0][0] |
||
| 690 | + dxOuter * span.attrStepX[VARYING_SLOT_TEX0][0]); |
||
| 691 | |||
| 692 | t0 = vLower->attrib[VARYING_SLOT_TEX0][1] * T_SCALE; |
||
| 693 | tLeft = (GLfixed)(t0 * FIXED_SCALE + span.attrStepX[VARYING_SLOT_TEX0][1] * adjx |
||
| 694 | + span.attrStepY[VARYING_SLOT_TEX0][1] * adjy) + FIXED_HALF; |
||
| 695 | dtOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_TEX0][1] |
||
| 696 | + dxOuter * span.attrStepX[VARYING_SLOT_TEX0][1]); |
||
| 697 | } |
||
| 698 | #endif |
||
| 699 | #ifdef INTERP_ATTRIBS |
||
| 700 | { |
||
| 701 | const GLuint attr = VARYING_SLOT_POS; |
||
| 702 | wLeft = vLower->attrib[VARYING_SLOT_POS][3] |
||
| 703 | + (span.attrStepX[attr][3] * adjx |
||
| 704 | + span.attrStepY[attr][3] * adjy) * (1.0F/FIXED_SCALE); |
||
| 705 | dwOuter = span.attrStepY[attr][3] + dxOuter * span.attrStepX[attr][3]; |
||
| 706 | } |
||
| 707 | ATTRIB_LOOP_BEGIN |
||
| 708 | const GLfloat invW = vLower->attrib[VARYING_SLOT_POS][3]; |
||
| 709 | if (swrast->_InterpMode[attr] == GL_FLAT) { |
||
| 710 | GLuint c; |
||
| 711 | for (c = 0; c < 4; c++) { |
||
| 712 | attrLeft[attr][c] = v2->attrib[attr][c] * invW; |
||
| 713 | daOuter[attr][c] = 0.0; |
||
| 714 | } |
||
| 715 | } |
||
| 716 | else { |
||
| 717 | GLuint c; |
||
| 718 | for (c = 0; c < 4; c++) { |
||
| 719 | const GLfloat a = vLower->attrib[attr][c] * invW; |
||
| 720 | attrLeft[attr][c] = a + ( span.attrStepX[attr][c] * adjx |
||
| 721 | + span.attrStepY[attr][c] * adjy) * (1.0F/FIXED_SCALE); |
||
| 722 | daOuter[attr][c] = span.attrStepY[attr][c] + dxOuter * span.attrStepX[attr][c]; |
||
| 723 | } |
||
| 724 | } |
||
| 725 | ATTRIB_LOOP_END |
||
| 726 | #endif |
||
| 727 | } /*if setupLeft*/ |
||
| 728 | |||
| 729 | |||
| 730 | if (setupRight && eRight->lines>0) { |
||
| 731 | fxRightEdge = eRight->fsx - FIXED_EPSILON; |
||
| 732 | fdxRightEdge = eRight->fdxdy; |
||
| 733 | } |
||
| 734 | |||
| 735 | if (lines==0) { |
||
| 736 | continue; |
||
| 737 | } |
||
| 738 | |||
| 739 | |||
| 740 | /* Rasterize setup */ |
||
| 741 | #ifdef PIXEL_ADDRESS |
||
| 742 | dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE); |
||
| 743 | #endif |
||
| 744 | #ifdef INTERP_Z |
||
| 745 | # ifdef DEPTH_TYPE |
||
| 746 | dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE); |
||
| 747 | # endif |
||
| 748 | fdzInner = fdzOuter + span.zStep; |
||
| 749 | #endif |
||
| 750 | #ifdef INTERP_RGB |
||
| 751 | fdrInner = fdrOuter + span.redStep; |
||
| 752 | fdgInner = fdgOuter + span.greenStep; |
||
| 753 | fdbInner = fdbOuter + span.blueStep; |
||
| 754 | #endif |
||
| 755 | #ifdef INTERP_ALPHA |
||
| 756 | fdaInner = fdaOuter + span.alphaStep; |
||
| 757 | #endif |
||
| 758 | #ifdef INTERP_INT_TEX |
||
| 759 | dsInner = dsOuter + span.intTexStep[0]; |
||
| 760 | dtInner = dtOuter + span.intTexStep[1]; |
||
| 761 | #endif |
||
| 762 | #ifdef INTERP_ATTRIBS |
||
| 763 | dwInner = dwOuter + span.attrStepX[VARYING_SLOT_POS][3]; |
||
| 764 | ATTRIB_LOOP_BEGIN |
||
| 765 | GLuint c; |
||
| 766 | for (c = 0; c < 4; c++) { |
||
| 767 | daInner[attr][c] = daOuter[attr][c] + span.attrStepX[attr][c]; |
||
| 768 | } |
||
| 769 | ATTRIB_LOOP_END |
||
| 770 | #endif |
||
| 771 | |||
| 772 | while (lines > 0) { |
||
| 773 | /* initialize the span interpolants to the leftmost value */ |
||
| 774 | /* ff = fixed-pt fragment */ |
||
| 775 | const GLint right = FixedToInt(fxRightEdge); |
||
| 776 | span.x = FixedToInt(fxLeftEdge); |
||
| 777 | if (right <= span.x) |
||
| 778 | span.end = 0; |
||
| 779 | else |
||
| 780 | span.end = right - span.x; |
||
| 781 | |||
| 782 | #ifdef INTERP_Z |
||
| 783 | span.z = zLeft; |
||
| 784 | #endif |
||
| 785 | #ifdef INTERP_RGB |
||
| 786 | span.red = rLeft; |
||
| 787 | span.green = gLeft; |
||
| 788 | span.blue = bLeft; |
||
| 789 | #endif |
||
| 790 | #ifdef INTERP_ALPHA |
||
| 791 | span.alpha = aLeft; |
||
| 792 | #endif |
||
| 793 | #ifdef INTERP_INT_TEX |
||
| 794 | span.intTex[0] = sLeft; |
||
| 795 | span.intTex[1] = tLeft; |
||
| 796 | #endif |
||
| 797 | |||
| 798 | #ifdef INTERP_ATTRIBS |
||
| 799 | span.attrStart[VARYING_SLOT_POS][3] = wLeft; |
||
| 800 | ATTRIB_LOOP_BEGIN |
||
| 801 | GLuint c; |
||
| 802 | for (c = 0; c < 4; c++) { |
||
| 803 | span.attrStart[attr][c] = attrLeft[attr][c]; |
||
| 804 | } |
||
| 805 | ATTRIB_LOOP_END |
||
| 806 | #endif |
||
| 807 | |||
| 808 | /* This is where we actually generate fragments */ |
||
| 809 | /* XXX the test for span.y > 0 _shouldn't_ be needed but |
||
| 810 | * it fixes a problem on 64-bit Opterons (bug 4842). |
||
| 811 | */ |
||
| 812 | if (span.end > 0 && span.y >= 0) { |
||
| 813 | const GLint len = span.end - 1; |
||
| 814 | (void) len; |
||
| 815 | #ifdef INTERP_RGB |
||
| 816 | CLAMP_INTERPOLANT(red, redStep, len); |
||
| 817 | CLAMP_INTERPOLANT(green, greenStep, len); |
||
| 818 | CLAMP_INTERPOLANT(blue, blueStep, len); |
||
| 819 | #endif |
||
| 820 | #ifdef INTERP_ALPHA |
||
| 821 | CLAMP_INTERPOLANT(alpha, alphaStep, len); |
||
| 822 | #endif |
||
| 823 | { |
||
| 824 | RENDER_SPAN( span ); |
||
| 825 | } |
||
| 826 | } |
||
| 827 | |||
| 828 | /* |
||
| 829 | * Advance to the next scan line. Compute the |
||
| 830 | * new edge coordinates, and adjust the |
||
| 831 | * pixel-center x coordinate so that it stays |
||
| 832 | * on or inside the major edge. |
||
| 833 | */ |
||
| 834 | span.y++; |
||
| 835 | lines--; |
||
| 836 | |||
| 837 | fxLeftEdge += fdxLeftEdge; |
||
| 838 | fxRightEdge += fdxRightEdge; |
||
| 839 | |||
| 840 | fError += fdError; |
||
| 841 | if (fError >= 0) { |
||
| 842 | fError -= FIXED_ONE; |
||
| 843 | |||
| 844 | #ifdef PIXEL_ADDRESS |
||
| 845 | pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter); |
||
| 846 | #endif |
||
| 847 | #ifdef INTERP_Z |
||
| 848 | # ifdef DEPTH_TYPE |
||
| 849 | zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter); |
||
| 850 | # endif |
||
| 851 | zLeft += fdzOuter; |
||
| 852 | #endif |
||
| 853 | #ifdef INTERP_RGB |
||
| 854 | rLeft += fdrOuter; |
||
| 855 | gLeft += fdgOuter; |
||
| 856 | bLeft += fdbOuter; |
||
| 857 | #endif |
||
| 858 | #ifdef INTERP_ALPHA |
||
| 859 | aLeft += fdaOuter; |
||
| 860 | #endif |
||
| 861 | #ifdef INTERP_INT_TEX |
||
| 862 | sLeft += dsOuter; |
||
| 863 | tLeft += dtOuter; |
||
| 864 | #endif |
||
| 865 | #ifdef INTERP_ATTRIBS |
||
| 866 | wLeft += dwOuter; |
||
| 867 | ATTRIB_LOOP_BEGIN |
||
| 868 | GLuint c; |
||
| 869 | for (c = 0; c < 4; c++) { |
||
| 870 | attrLeft[attr][c] += daOuter[attr][c]; |
||
| 871 | } |
||
| 872 | ATTRIB_LOOP_END |
||
| 873 | #endif |
||
| 874 | } |
||
| 875 | else { |
||
| 876 | #ifdef PIXEL_ADDRESS |
||
| 877 | pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner); |
||
| 878 | #endif |
||
| 879 | #ifdef INTERP_Z |
||
| 880 | # ifdef DEPTH_TYPE |
||
| 881 | zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner); |
||
| 882 | # endif |
||
| 883 | zLeft += fdzInner; |
||
| 884 | #endif |
||
| 885 | #ifdef INTERP_RGB |
||
| 886 | rLeft += fdrInner; |
||
| 887 | gLeft += fdgInner; |
||
| 888 | bLeft += fdbInner; |
||
| 889 | #endif |
||
| 890 | #ifdef INTERP_ALPHA |
||
| 891 | aLeft += fdaInner; |
||
| 892 | #endif |
||
| 893 | #ifdef INTERP_INT_TEX |
||
| 894 | sLeft += dsInner; |
||
| 895 | tLeft += dtInner; |
||
| 896 | #endif |
||
| 897 | #ifdef INTERP_ATTRIBS |
||
| 898 | wLeft += dwInner; |
||
| 899 | ATTRIB_LOOP_BEGIN |
||
| 900 | GLuint c; |
||
| 901 | for (c = 0; c < 4; c++) { |
||
| 902 | attrLeft[attr][c] += daInner[attr][c]; |
||
| 903 | } |
||
| 904 | ATTRIB_LOOP_END |
||
| 905 | #endif |
||
| 906 | } |
||
| 907 | } /*while lines>0*/ |
||
| 908 | |||
| 909 | } /* for subTriangle */ |
||
| 910 | |||
| 911 | } |
||
| 912 | } |
||
| 913 | } |
||
| 914 | |||
| 915 | #undef SETUP_CODE |
||
| 916 | #undef RENDER_SPAN |
||
| 917 | |||
| 918 | #undef PIXEL_TYPE |
||
| 919 | #undef BYTES_PER_ROW |
||
| 920 | #undef PIXEL_ADDRESS |
||
| 921 | #undef DEPTH_TYPE |
||
| 922 | |||
| 923 | #undef INTERP_Z |
||
| 924 | #undef INTERP_RGB |
||
| 925 | #undef INTERP_ALPHA |
||
| 926 | #undef INTERP_INT_TEX |
||
| 927 | #undef INTERP_ATTRIBS |
||
| 928 | |||
| 929 | #undef S_SCALE |
||
| 930 | #undef T_SCALE |
||
| 931 | |||
| 932 | #undef FixedToDepth |
||
| 933 | |||
| 934 | #undef NAME |