| 0,0 → 1,312 |
|---|
| /* |
| * Mesa 3-D graphics library |
| * |
| * Copyright (C) 1999-2007 Brian Paul All Rights Reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included |
| * in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
| * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| * OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| |
| /* |
| * Antialiased Triangle rasterizers |
| */ |
| |
| |
| #include "main/glheader.h" |
| #include "main/context.h" |
| #include "main/colormac.h" |
| #include "main/macros.h" |
| #include "main/imports.h" |
| #include "main/state.h" |
| #include "s_aatriangle.h" |
| #include "s_context.h" |
| #include "s_span.h" |
| |
| |
| /* |
| * Compute coefficients of a plane using the X,Y coords of the v0, v1, v2 |
| * vertices and the given Z values. |
| * A point (x,y,z) lies on plane iff a*x+b*y+c*z+d = 0. |
| */ |
| static inline void |
| compute_plane(const GLfloat v0[], const GLfloat v1[], const GLfloat v2[], |
| GLfloat z0, GLfloat z1, GLfloat z2, GLfloat plane[4]) |
| { |
| const GLfloat px = v1[0] - v0[0]; |
| const GLfloat py = v1[1] - v0[1]; |
| const GLfloat pz = z1 - z0; |
| |
| const GLfloat qx = v2[0] - v0[0]; |
| const GLfloat qy = v2[1] - v0[1]; |
| const GLfloat qz = z2 - z0; |
| |
| /* Crossproduct "(a,b,c):= dv1 x dv2" is orthogonal to plane. */ |
| const GLfloat a = py * qz - pz * qy; |
| const GLfloat b = pz * qx - px * qz; |
| const GLfloat c = px * qy - py * qx; |
| /* Point on the plane = "r*(a,b,c) + w", with fixed "r" depending |
| on the distance of plane from origin and arbitrary "w" parallel |
| to the plane. */ |
| /* The scalar product "(r*(a,b,c)+w)*(a,b,c)" is "r*(a^2+b^2+c^2)", |
| which is equal to "-d" below. */ |
| const GLfloat d = -(a * v0[0] + b * v0[1] + c * z0); |
| |
| plane[0] = a; |
| plane[1] = b; |
| plane[2] = c; |
| plane[3] = d; |
| } |
| |
| |
| /* |
| * Compute coefficients of a plane with a constant Z value. |
| */ |
| static inline void |
| constant_plane(GLfloat value, GLfloat plane[4]) |
| { |
| plane[0] = 0.0; |
| plane[1] = 0.0; |
| plane[2] = -1.0; |
| plane[3] = value; |
| } |
| |
| #define CONSTANT_PLANE(VALUE, PLANE) \ |
| do { \ |
| PLANE[0] = 0.0F; \ |
| PLANE[1] = 0.0F; \ |
| PLANE[2] = -1.0F; \ |
| PLANE[3] = VALUE; \ |
| } while (0) |
| |
| |
| |
| /* |
| * Solve plane equation for Z at (X,Y). |
| */ |
| static inline GLfloat |
| solve_plane(GLfloat x, GLfloat y, const GLfloat plane[4]) |
| { |
| ASSERT(plane[2] != 0.0F); |
| return (plane[3] + plane[0] * x + plane[1] * y) / -plane[2]; |
| } |
| |
| |
| #define SOLVE_PLANE(X, Y, PLANE) \ |
| ((PLANE[3] + PLANE[0] * (X) + PLANE[1] * (Y)) / -PLANE[2]) |
| |
| |
| /* |
| * Return 1 / solve_plane(). |
| */ |
| static inline GLfloat |
| solve_plane_recip(GLfloat x, GLfloat y, const GLfloat plane[4]) |
| { |
| const GLfloat denom = plane[3] + plane[0] * x + plane[1] * y; |
| if (denom == 0.0F) |
| return 0.0F; |
| else |
| return -plane[2] / denom; |
| } |
| |
| |
| /* |
| * Solve plane and return clamped GLchan value. |
| */ |
| static inline GLchan |
| solve_plane_chan(GLfloat x, GLfloat y, const GLfloat plane[4]) |
| { |
| const GLfloat z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2]; |
| #if CHAN_TYPE == GL_FLOAT |
| return CLAMP(z, 0.0F, CHAN_MAXF); |
| #else |
| if (z < 0) |
| return 0; |
| else if (z > CHAN_MAX) |
| return CHAN_MAX; |
| return (GLchan) IROUND_POS(z); |
| #endif |
| } |
| |
| |
| static inline GLfloat |
| plane_dx(const GLfloat plane[4]) |
| { |
| return -plane[0] / plane[2]; |
| } |
| |
| static inline GLfloat |
| plane_dy(const GLfloat plane[4]) |
| { |
| return -plane[1] / plane[2]; |
| } |
| |
| |
| |
| /* |
| * Compute how much (area) of the given pixel is inside the triangle. |
| * Vertices MUST be specified in counter-clockwise order. |
| * Return: coverage in [0, 1]. |
| */ |
| static GLfloat |
| compute_coveragef(const GLfloat v0[3], const GLfloat v1[3], |
| const GLfloat v2[3], GLint winx, GLint winy) |
| { |
| /* Given a position [0,3]x[0,3] return the sub-pixel sample position. |
| * Contributed by Ray Tice. |
| * |
| * Jitter sample positions - |
| * - average should be .5 in x & y for each column |
| * - each of the 16 rows and columns should be used once |
| * - the rectangle formed by the first four points |
| * should contain the other points |
| * - the distrubition should be fairly even in any given direction |
| * |
| * The pattern drawn below isn't optimal, but it's better than a regular |
| * grid. In the drawing, the center of each subpixel is surrounded by |
| * four dots. The "x" marks the jittered position relative to the |
| * subpixel center. |
| */ |
| #define POS(a, b) (0.5+a*4+b)/16 |
| static const GLfloat samples[16][2] = { |
| /* start with the four corners */ |
| { POS(0, 2), POS(0, 0) }, |
| { POS(3, 3), POS(0, 2) }, |
| { POS(0, 0), POS(3, 1) }, |
| { POS(3, 1), POS(3, 3) }, |
| /* continue with interior samples */ |
| { POS(1, 1), POS(0, 1) }, |
| { POS(2, 0), POS(0, 3) }, |
| { POS(0, 3), POS(1, 3) }, |
| { POS(1, 2), POS(1, 0) }, |
| { POS(2, 3), POS(1, 2) }, |
| { POS(3, 2), POS(1, 1) }, |
| { POS(0, 1), POS(2, 2) }, |
| { POS(1, 0), POS(2, 1) }, |
| { POS(2, 1), POS(2, 3) }, |
| { POS(3, 0), POS(2, 0) }, |
| { POS(1, 3), POS(3, 0) }, |
| { POS(2, 2), POS(3, 2) } |
| }; |
| |
| const GLfloat x = (GLfloat) winx; |
| const GLfloat y = (GLfloat) winy; |
| const GLfloat dx0 = v1[0] - v0[0]; |
| const GLfloat dy0 = v1[1] - v0[1]; |
| const GLfloat dx1 = v2[0] - v1[0]; |
| const GLfloat dy1 = v2[1] - v1[1]; |
| const GLfloat dx2 = v0[0] - v2[0]; |
| const GLfloat dy2 = v0[1] - v2[1]; |
| GLint stop = 4, i; |
| GLfloat insideCount = 16.0F; |
| |
| ASSERT(dx0 * dy1 - dx1 * dy0 >= 0.0); /* area >= 0.0 */ |
| |
| for (i = 0; i < stop; i++) { |
| const GLfloat sx = x + samples[i][0]; |
| const GLfloat sy = y + samples[i][1]; |
| /* cross product determines if sample is inside or outside each edge */ |
| GLfloat cross = (dx0 * (sy - v0[1]) - dy0 * (sx - v0[0])); |
| /* Check if the sample is exactly on an edge. If so, let cross be a |
| * positive or negative value depending on the direction of the edge. |
| */ |
| if (cross == 0.0F) |
| cross = dx0 + dy0; |
| if (cross < 0.0F) { |
| /* sample point is outside first edge */ |
| insideCount -= 1.0F; |
| stop = 16; |
| } |
| else { |
| /* sample point is inside first edge */ |
| cross = (dx1 * (sy - v1[1]) - dy1 * (sx - v1[0])); |
| if (cross == 0.0F) |
| cross = dx1 + dy1; |
| if (cross < 0.0F) { |
| /* sample point is outside second edge */ |
| insideCount -= 1.0F; |
| stop = 16; |
| } |
| else { |
| /* sample point is inside first and second edges */ |
| cross = (dx2 * (sy - v2[1]) - dy2 * (sx - v2[0])); |
| if (cross == 0.0F) |
| cross = dx2 + dy2; |
| if (cross < 0.0F) { |
| /* sample point is outside third edge */ |
| insideCount -= 1.0F; |
| stop = 16; |
| } |
| } |
| } |
| } |
| if (stop == 4) |
| return 1.0F; |
| else |
| return insideCount * (1.0F / 16.0F); |
| } |
| |
| |
| |
| static void |
| rgba_aa_tri(struct gl_context *ctx, |
| const SWvertex *v0, |
| const SWvertex *v1, |
| const SWvertex *v2) |
| { |
| #define DO_Z |
| #include "s_aatritemp.h" |
| } |
| |
| |
| static void |
| general_aa_tri(struct gl_context *ctx, |
| const SWvertex *v0, |
| const SWvertex *v1, |
| const SWvertex *v2) |
| { |
| #define DO_Z |
| #define DO_ATTRIBS |
| #include "s_aatritemp.h" |
| } |
| |
| |
| |
| /* |
| * Examine GL state and set swrast->Triangle to an |
| * appropriate antialiased triangle rasterizer function. |
| */ |
| void |
| _swrast_set_aa_triangle_function(struct gl_context *ctx) |
| { |
| SWcontext *swrast = SWRAST_CONTEXT(ctx); |
| |
| ASSERT(ctx->Polygon.SmoothFlag); |
| |
| if (ctx->Texture._EnabledCoordUnits != 0 |
| || _swrast_use_fragment_program(ctx) |
| || swrast->_FogEnabled |
| || _mesa_need_secondary_color(ctx)) { |
| SWRAST_CONTEXT(ctx)->Triangle = general_aa_tri; |
| } |
| else { |
| SWRAST_CONTEXT(ctx)->Triangle = rgba_aa_tri; |
| } |
| |
| ASSERT(SWRAST_CONTEXT(ctx)->Triangle); |
| } |