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  1. /*
  2.  * Mesa 3-D graphics library
  3.  * Version:  7.0
  4.  *
  5.  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
  6.  *
  7.  * Permission is hereby granted, free of charge, to any person obtaining a
  8.  * copy of this software and associated documentation files (the "Software"),
  9.  * to deal in the Software without restriction, including without limitation
  10.  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11.  * and/or sell copies of the Software, and to permit persons to whom the
  12.  * Software is furnished to do so, subject to the following conditions:
  13.  *
  14.  * The above copyright notice and this permission notice shall be included
  15.  * in all copies or substantial portions of the Software.
  16.  *
  17.  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18.  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19.  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20.  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21.  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22.  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23.  */
  24.  
  25. /*
  26.  * Triangle Rasterizer Template
  27.  *
  28.  * This file is #include'd to generate custom triangle rasterizers.
  29.  *
  30.  * The following macros may be defined to indicate what auxillary information
  31.  * must be interpolated across the triangle:
  32.  *    INTERP_Z        - if defined, interpolate integer Z values
  33.  *    INTERP_RGB      - if defined, interpolate integer RGB values
  34.  *    INTERP_ALPHA    - if defined, interpolate integer Alpha values
  35.  *    INTERP_INT_TEX  - if defined, interpolate integer ST texcoords
  36.  *                         (fast, simple 2-D texture mapping, without
  37.  *                         perspective correction)
  38.  *    INTERP_ATTRIBS  - if defined, interpolate arbitrary attribs (texcoords,
  39.  *                         varying vars, etc)  This also causes W to be
  40.  *                         computed for perspective correction).
  41.  *
  42.  * When one can directly address pixels in the color buffer the following
  43.  * macros can be defined and used to compute pixel addresses during
  44.  * rasterization (see pRow):
  45.  *    PIXEL_TYPE          - the datatype of a pixel (GLubyte, GLushort, GLuint)
  46.  *    BYTES_PER_ROW       - number of bytes per row in the color buffer
  47.  *    PIXEL_ADDRESS(X,Y)  - returns the address of pixel at (X,Y) where
  48.  *                          Y==0 at bottom of screen and increases upward.
  49.  *
  50.  * Similarly, for direct depth buffer access, this type is used for depth
  51.  * buffer addressing (see zRow):
  52.  *    DEPTH_TYPE          - either GLushort or GLuint
  53.  *
  54.  * Optionally, one may provide one-time setup code per triangle:
  55.  *    SETUP_CODE    - code which is to be executed once per triangle
  56.  *
  57.  * The following macro MUST be defined:
  58.  *    RENDER_SPAN(span) - code to write a span of pixels.
  59.  *
  60.  * This code was designed for the origin to be in the lower-left corner.
  61.  *
  62.  * Inspired by triangle rasterizer code written by Allen Akin.  Thanks Allen!
  63.  *
  64.  *
  65.  * Some notes on rasterization accuracy:
  66.  *
  67.  * This code uses fixed point arithmetic (the GLfixed type) to iterate
  68.  * over the triangle edges and interpolate ancillary data (such as Z,
  69.  * color, secondary color, etc).  The number of fractional bits in
  70.  * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the
  71.  * accuracy of rasterization.
  72.  *
  73.  * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest
  74.  * 1/16 of a pixel.  If we're walking up a long, nearly vertical edge
  75.  * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in
  76.  * GLfixed to walk the edge without error.  If the maximum viewport
  77.  * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits.
  78.  *
  79.  * Historically, Mesa has used 11 fractional bits in GLfixed, snaps
  80.  * vertices to 1/16 pixel and allowed a maximum viewport height of 2K
  81.  * pixels.  11 fractional bits is actually insufficient for accurately
  82.  * rasterizing some triangles.  More recently, the maximum viewport
  83.  * height was increased to 4K pixels.  Thus, Mesa should be using 16
  84.  * fractional bits in GLfixed.  Unfortunately, there may be some issues
  85.  * with setting FIXED_FRAC_BITS=16, such as multiplication overflow.
  86.  * This will have to be examined in some detail...
  87.  *
  88.  * For now, if you find rasterization errors, particularly with tall,
  89.  * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing
  90.  * SUB_PIXEL_BITS.
  91.  */
  92.  
  93.  
  94. /*
  95.  * Some code we unfortunately need to prevent negative interpolated colors.
  96.  */
  97. #ifndef CLAMP_INTERPOLANT
  98. #define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN)            \
  99. do {                                                            \
  100.    GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP;    \
  101.    if (endVal < 0) {                                            \
  102.       span.CHANNEL -= endVal;                                   \
  103.    }                                                            \
  104.    if (span.CHANNEL < 0) {                                      \
  105.       span.CHANNEL = 0;                                         \
  106.    }                                                            \
  107. } while (0)
  108. #endif
  109.  
  110.  
  111. static void NAME(struct gl_context *ctx, const SWvertex *v0,
  112.                                  const SWvertex *v1,
  113.                                  const SWvertex *v2 )
  114. {
  115.    typedef struct {
  116.       const SWvertex *v0, *v1;   /* Y(v0) < Y(v1) */
  117.       GLfloat dx;       /* X(v1) - X(v0) */
  118.       GLfloat dy;       /* Y(v1) - Y(v0) */
  119.       GLfloat dxdy;     /* dx/dy */
  120.       GLfixed fdxdy;    /* dx/dy in fixed-point */
  121.       GLfloat adjy;     /* adjust from v[0]->fy to fsy, scaled */
  122.       GLfixed fsx;      /* first sample point x coord */
  123.       GLfixed fsy;
  124.       GLfixed fx0;      /* fixed pt X of lower endpoint */
  125.       GLint lines;      /* number of lines to be sampled on this edge */
  126.    } EdgeT;
  127.  
  128.    const SWcontext *swrast = SWRAST_CONTEXT(ctx);
  129. #ifdef INTERP_Z
  130.    const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
  131.    const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
  132.    const GLfloat maxDepth = ctx->DrawBuffer->_DepthMaxF;
  133. #define FixedToDepth(F)  ((F) >> fixedToDepthShift)
  134. #endif
  135.    EdgeT eMaj, eTop, eBot;
  136.    GLfloat oneOverArea;
  137.    const SWvertex *vMin, *vMid, *vMax;  /* Y(vMin)<=Y(vMid)<=Y(vMax) */
  138.    GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign;
  139.    const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */
  140.    GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy;
  141.  
  142.    SWspan span;
  143.  
  144.    (void) swrast;
  145.  
  146.    INIT_SPAN(span, GL_POLYGON);
  147.    span.y = 0; /* silence warnings */
  148.  
  149. #ifdef INTERP_Z
  150.    (void) fixedToDepthShift;
  151. #endif
  152.  
  153.    /*
  154.    printf("%s()\n", __FUNCTION__);
  155.    printf("  %g, %g, %g\n",
  156.           v0->attrib[FRAG_ATTRIB_WPOS][0],
  157.           v0->attrib[FRAG_ATTRIB_WPOS][1],
  158.           v0->attrib[FRAG_ATTRIB_WPOS][2]);
  159.    printf("  %g, %g, %g\n",
  160.           v1->attrib[FRAG_ATTRIB_WPOS][0],
  161.           v1->attrib[FRAG_ATTRIB_WPOS][1],
  162.           v1->attrib[FRAG_ATTRIB_WPOS][2]);
  163.    printf("  %g, %g, %g\n",
  164.           v2->attrib[FRAG_ATTRIB_WPOS][0],
  165.           v2->attrib[FRAG_ATTRIB_WPOS][1],
  166.           v2->attrib[FRAG_ATTRIB_WPOS][2]);
  167.    */
  168.  
  169.    /* Compute fixed point x,y coords w/ half-pixel offsets and snapping.
  170.     * And find the order of the 3 vertices along the Y axis.
  171.     */
  172.    {
  173.       const GLfixed fy0 = FloatToFixed(v0->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
  174.       const GLfixed fy1 = FloatToFixed(v1->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
  175.       const GLfixed fy2 = FloatToFixed(v2->attrib[FRAG_ATTRIB_WPOS][1] - 0.5F) & snapMask;
  176.       if (fy0 <= fy1) {
  177.          if (fy1 <= fy2) {
  178.             /* y0 <= y1 <= y2 */
  179.             vMin = v0;   vMid = v1;   vMax = v2;
  180.             vMin_fy = fy0;  vMid_fy = fy1;  vMax_fy = fy2;
  181.          }
  182.          else if (fy2 <= fy0) {
  183.             /* y2 <= y0 <= y1 */
  184.             vMin = v2;   vMid = v0;   vMax = v1;
  185.             vMin_fy = fy2;  vMid_fy = fy0;  vMax_fy = fy1;
  186.          }
  187.          else {
  188.             /* y0 <= y2 <= y1 */
  189.             vMin = v0;   vMid = v2;   vMax = v1;
  190.             vMin_fy = fy0;  vMid_fy = fy2;  vMax_fy = fy1;
  191.             bf = -bf;
  192.          }
  193.       }
  194.       else {
  195.          if (fy0 <= fy2) {
  196.             /* y1 <= y0 <= y2 */
  197.             vMin = v1;   vMid = v0;   vMax = v2;
  198.             vMin_fy = fy1;  vMid_fy = fy0;  vMax_fy = fy2;
  199.             bf = -bf;
  200.          }
  201.          else if (fy2 <= fy1) {
  202.             /* y2 <= y1 <= y0 */
  203.             vMin = v2;   vMid = v1;   vMax = v0;
  204.             vMin_fy = fy2;  vMid_fy = fy1;  vMax_fy = fy0;
  205.             bf = -bf;
  206.          }
  207.          else {
  208.             /* y1 <= y2 <= y0 */
  209.             vMin = v1;   vMid = v2;   vMax = v0;
  210.             vMin_fy = fy1;  vMid_fy = fy2;  vMax_fy = fy0;
  211.          }
  212.       }
  213.  
  214.       /* fixed point X coords */
  215.       vMin_fx = FloatToFixed(vMin->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
  216.       vMid_fx = FloatToFixed(vMid->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
  217.       vMax_fx = FloatToFixed(vMax->attrib[FRAG_ATTRIB_WPOS][0] + 0.5F) & snapMask;
  218.    }
  219.  
  220.    /* vertex/edge relationship */
  221.    eMaj.v0 = vMin;   eMaj.v1 = vMax;   /*TODO: .v1's not needed */
  222.    eTop.v0 = vMid;   eTop.v1 = vMax;
  223.    eBot.v0 = vMin;   eBot.v1 = vMid;
  224.  
  225.    /* compute deltas for each edge:  vertex[upper] - vertex[lower] */
  226.    eMaj.dx = FixedToFloat(vMax_fx - vMin_fx);
  227.    eMaj.dy = FixedToFloat(vMax_fy - vMin_fy);
  228.    eTop.dx = FixedToFloat(vMax_fx - vMid_fx);
  229.    eTop.dy = FixedToFloat(vMax_fy - vMid_fy);
  230.    eBot.dx = FixedToFloat(vMid_fx - vMin_fx);
  231.    eBot.dy = FixedToFloat(vMid_fy - vMin_fy);
  232.  
  233.    /* compute area, oneOverArea and perform backface culling */
  234.    {
  235.       const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy;
  236.  
  237.       if (IS_INF_OR_NAN(area) || area == 0.0F)
  238.          return;
  239.  
  240.       if (area * bf * swrast->_BackfaceCullSign < 0.0)
  241.          return;
  242.  
  243.       oneOverArea = 1.0F / area;
  244.  
  245.       /* 0 = front, 1 = back */
  246.       span.facing = oneOverArea * bf > 0.0F;
  247.    }
  248.  
  249.    /* Edge setup.  For a triangle strip these could be reused... */
  250.    {
  251.       eMaj.fsy = FixedCeil(vMin_fy);
  252.       eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy));
  253.       if (eMaj.lines > 0) {
  254.          eMaj.dxdy = eMaj.dx / eMaj.dy;
  255.          eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy);
  256.          eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy);  /* SCALED! */
  257.          eMaj.fx0 = vMin_fx;
  258.          eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy);
  259.       }
  260.       else {
  261.          return;  /*CULLED*/
  262.       }
  263.  
  264.       eTop.fsy = FixedCeil(vMid_fy);
  265.       eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy));
  266.       if (eTop.lines > 0) {
  267.          eTop.dxdy = eTop.dx / eTop.dy;
  268.          eTop.fdxdy = SignedFloatToFixed(eTop.dxdy);
  269.          eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */
  270.          eTop.fx0 = vMid_fx;
  271.          eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy);
  272.       }
  273.  
  274.       eBot.fsy = FixedCeil(vMin_fy);
  275.       eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy));
  276.       if (eBot.lines > 0) {
  277.          eBot.dxdy = eBot.dx / eBot.dy;
  278.          eBot.fdxdy = SignedFloatToFixed(eBot.dxdy);
  279.          eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy);  /* SCALED! */
  280.          eBot.fx0 = vMin_fx;
  281.          eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy);
  282.       }
  283.    }
  284.  
  285.    /*
  286.     * Conceptually, we view a triangle as two subtriangles
  287.     * separated by a perfectly horizontal line.  The edge that is
  288.     * intersected by this line is one with maximal absolute dy; we
  289.     * call it a ``major'' edge.  The other two edges are the
  290.     * ``top'' edge (for the upper subtriangle) and the ``bottom''
  291.     * edge (for the lower subtriangle).  If either of these two
  292.     * edges is horizontal or very close to horizontal, the
  293.     * corresponding subtriangle might cover zero sample points;
  294.     * we take care to handle such cases, for performance as well
  295.     * as correctness.
  296.     *
  297.     * By stepping rasterization parameters along the major edge,
  298.     * we can avoid recomputing them at the discontinuity where
  299.     * the top and bottom edges meet.  However, this forces us to
  300.     * be able to scan both left-to-right and right-to-left.
  301.     * Also, we must determine whether the major edge is at the
  302.     * left or right side of the triangle.  We do this by
  303.     * computing the magnitude of the cross-product of the major
  304.     * and top edges.  Since this magnitude depends on the sine of
  305.     * the angle between the two edges, its sign tells us whether
  306.     * we turn to the left or to the right when travelling along
  307.     * the major edge to the top edge, and from this we infer
  308.     * whether the major edge is on the left or the right.
  309.     *
  310.     * Serendipitously, this cross-product magnitude is also a
  311.     * value we need to compute the iteration parameter
  312.     * derivatives for the triangle, and it can be used to perform
  313.     * backface culling because its sign tells us whether the
  314.     * triangle is clockwise or counterclockwise.  In this code we
  315.     * refer to it as ``area'' because it's also proportional to
  316.     * the pixel area of the triangle.
  317.     */
  318.  
  319.    {
  320.       GLint scan_from_left_to_right;  /* true if scanning left-to-right */
  321.  
  322.       /*
  323.        * Execute user-supplied setup code
  324.        */
  325. #ifdef SETUP_CODE
  326.       SETUP_CODE
  327. #endif
  328.  
  329.       scan_from_left_to_right = (oneOverArea < 0.0F);
  330.  
  331.  
  332.       /* compute d?/dx and d?/dy derivatives */
  333. #ifdef INTERP_Z
  334.       span.interpMask |= SPAN_Z;
  335.       {
  336.          GLfloat eMaj_dz = vMax->attrib[FRAG_ATTRIB_WPOS][2] - vMin->attrib[FRAG_ATTRIB_WPOS][2];
  337.          GLfloat eBot_dz = vMid->attrib[FRAG_ATTRIB_WPOS][2] - vMin->attrib[FRAG_ATTRIB_WPOS][2];
  338.          span.attrStepX[FRAG_ATTRIB_WPOS][2] = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz);
  339.          if (span.attrStepX[FRAG_ATTRIB_WPOS][2] > maxDepth ||
  340.              span.attrStepX[FRAG_ATTRIB_WPOS][2] < -maxDepth) {
  341.             /* probably a sliver triangle */
  342.             span.attrStepX[FRAG_ATTRIB_WPOS][2] = 0.0;
  343.             span.attrStepY[FRAG_ATTRIB_WPOS][2] = 0.0;
  344.          }
  345.          else {
  346.             span.attrStepY[FRAG_ATTRIB_WPOS][2] = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx);
  347.          }
  348.          if (depthBits <= 16)
  349.             span.zStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_WPOS][2]);
  350.          else
  351.             span.zStep = (GLint) span.attrStepX[FRAG_ATTRIB_WPOS][2];
  352.       }
  353. #endif
  354. #ifdef INTERP_RGB
  355.       span.interpMask |= SPAN_RGBA;
  356.       if (ctx->Light.ShadeModel == GL_SMOOTH) {
  357.          GLfloat eMaj_dr = (GLfloat) (vMax->color[RCOMP] - vMin->color[RCOMP]);
  358.          GLfloat eBot_dr = (GLfloat) (vMid->color[RCOMP] - vMin->color[RCOMP]);
  359.          GLfloat eMaj_dg = (GLfloat) (vMax->color[GCOMP] - vMin->color[GCOMP]);
  360.          GLfloat eBot_dg = (GLfloat) (vMid->color[GCOMP] - vMin->color[GCOMP]);
  361.          GLfloat eMaj_db = (GLfloat) (vMax->color[BCOMP] - vMin->color[BCOMP]);
  362.          GLfloat eBot_db = (GLfloat) (vMid->color[BCOMP] - vMin->color[BCOMP]);
  363. #  ifdef INTERP_ALPHA
  364.          GLfloat eMaj_da = (GLfloat) (vMax->color[ACOMP] - vMin->color[ACOMP]);
  365.          GLfloat eBot_da = (GLfloat) (vMid->color[ACOMP] - vMin->color[ACOMP]);
  366. #  endif
  367.          span.attrStepX[FRAG_ATTRIB_COL0][0] = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr);
  368.          span.attrStepY[FRAG_ATTRIB_COL0][0] = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx);
  369.          span.attrStepX[FRAG_ATTRIB_COL0][1] = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg);
  370.          span.attrStepY[FRAG_ATTRIB_COL0][1] = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx);
  371.          span.attrStepX[FRAG_ATTRIB_COL0][2] = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db);
  372.          span.attrStepY[FRAG_ATTRIB_COL0][2] = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx);
  373.          span.redStep   = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][0]);
  374.          span.greenStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][1]);
  375.          span.blueStep  = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][2]);
  376. #  ifdef INTERP_ALPHA
  377.          span.attrStepX[FRAG_ATTRIB_COL0][3] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
  378.          span.attrStepY[FRAG_ATTRIB_COL0][3] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
  379.          span.alphaStep = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_COL0][3]);
  380. #  endif /* INTERP_ALPHA */
  381.       }
  382.       else {
  383.          ASSERT(ctx->Light.ShadeModel == GL_FLAT);
  384.          span.interpMask |= SPAN_FLAT;
  385.          span.attrStepX[FRAG_ATTRIB_COL0][0] = span.attrStepY[FRAG_ATTRIB_COL0][0] = 0.0F;
  386.          span.attrStepX[FRAG_ATTRIB_COL0][1] = span.attrStepY[FRAG_ATTRIB_COL0][1] = 0.0F;
  387.          span.attrStepX[FRAG_ATTRIB_COL0][2] = span.attrStepY[FRAG_ATTRIB_COL0][2] = 0.0F;
  388.          span.redStep   = 0;
  389.          span.greenStep = 0;
  390.          span.blueStep  = 0;
  391. #  ifdef INTERP_ALPHA
  392.          span.attrStepX[FRAG_ATTRIB_COL0][3] = span.attrStepY[FRAG_ATTRIB_COL0][3] = 0.0F;
  393.          span.alphaStep = 0;
  394. #  endif
  395.       }
  396. #endif /* INTERP_RGB */
  397. #ifdef INTERP_INT_TEX
  398.       {
  399.          GLfloat eMaj_ds = (vMax->attrib[FRAG_ATTRIB_TEX0][0] - vMin->attrib[FRAG_ATTRIB_TEX0][0]) * S_SCALE;
  400.          GLfloat eBot_ds = (vMid->attrib[FRAG_ATTRIB_TEX0][0] - vMin->attrib[FRAG_ATTRIB_TEX0][0]) * S_SCALE;
  401.          GLfloat eMaj_dt = (vMax->attrib[FRAG_ATTRIB_TEX0][1] - vMin->attrib[FRAG_ATTRIB_TEX0][1]) * T_SCALE;
  402.          GLfloat eBot_dt = (vMid->attrib[FRAG_ATTRIB_TEX0][1] - vMin->attrib[FRAG_ATTRIB_TEX0][1]) * T_SCALE;
  403.          span.attrStepX[FRAG_ATTRIB_TEX0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds);
  404.          span.attrStepY[FRAG_ATTRIB_TEX0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx);
  405.          span.attrStepX[FRAG_ATTRIB_TEX0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt);
  406.          span.attrStepY[FRAG_ATTRIB_TEX0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx);
  407.          span.intTexStep[0] = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_TEX0][0]);
  408.          span.intTexStep[1] = SignedFloatToFixed(span.attrStepX[FRAG_ATTRIB_TEX0][1]);
  409.       }
  410. #endif
  411. #ifdef INTERP_ATTRIBS
  412.       {
  413.          /* attrib[FRAG_ATTRIB_WPOS][3] is 1/W */
  414.          const GLfloat wMax = vMax->attrib[FRAG_ATTRIB_WPOS][3];
  415.          const GLfloat wMin = vMin->attrib[FRAG_ATTRIB_WPOS][3];
  416.          const GLfloat wMid = vMid->attrib[FRAG_ATTRIB_WPOS][3];
  417.          {
  418.             const GLfloat eMaj_dw = wMax - wMin;
  419.             const GLfloat eBot_dw = wMid - wMin;
  420.             span.attrStepX[FRAG_ATTRIB_WPOS][3] = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw);
  421.             span.attrStepY[FRAG_ATTRIB_WPOS][3] = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx);
  422.          }
  423.          ATTRIB_LOOP_BEGIN
  424.             if (swrast->_InterpMode[attr] == GL_FLAT) {
  425.                ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0);
  426.                ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0);
  427.             }
  428.             else {
  429.                GLuint c;
  430.                for (c = 0; c < 4; c++) {
  431.                   GLfloat eMaj_da = vMax->attrib[attr][c] * wMax - vMin->attrib[attr][c] * wMin;
  432.                   GLfloat eBot_da = vMid->attrib[attr][c] * wMid - vMin->attrib[attr][c] * wMin;
  433.                   span.attrStepX[attr][c] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da);
  434.                   span.attrStepY[attr][c] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx);
  435.                }
  436.             }
  437.          ATTRIB_LOOP_END
  438.       }
  439. #endif
  440.  
  441.       /*
  442.        * We always sample at pixel centers.  However, we avoid
  443.        * explicit half-pixel offsets in this code by incorporating
  444.        * the proper offset in each of x and y during the
  445.        * transformation to window coordinates.
  446.        *
  447.        * We also apply the usual rasterization rules to prevent
  448.        * cracks and overlaps.  A pixel is considered inside a
  449.        * subtriangle if it meets all of four conditions: it is on or
  450.        * to the right of the left edge, strictly to the left of the
  451.        * right edge, on or below the top edge, and strictly above
  452.        * the bottom edge.  (Some edges may be degenerate.)
  453.        *
  454.        * The following discussion assumes left-to-right scanning
  455.        * (that is, the major edge is on the left); the right-to-left
  456.        * case is a straightforward variation.
  457.        *
  458.        * We start by finding the half-integral y coordinate that is
  459.        * at or below the top of the triangle.  This gives us the
  460.        * first scan line that could possibly contain pixels that are
  461.        * inside the triangle.
  462.        *
  463.        * Next we creep down the major edge until we reach that y,
  464.        * and compute the corresponding x coordinate on the edge.
  465.        * Then we find the half-integral x that lies on or just
  466.        * inside the edge.  This is the first pixel that might lie in
  467.        * the interior of the triangle.  (We won't know for sure
  468.        * until we check the other edges.)
  469.        *
  470.        * As we rasterize the triangle, we'll step down the major
  471.        * edge.  For each step in y, we'll move an integer number
  472.        * of steps in x.  There are two possible x step sizes, which
  473.        * we'll call the ``inner'' step (guaranteed to land on the
  474.        * edge or inside it) and the ``outer'' step (guaranteed to
  475.        * land on the edge or outside it).  The inner and outer steps
  476.        * differ by one.  During rasterization we maintain an error
  477.        * term that indicates our distance from the true edge, and
  478.        * select either the inner step or the outer step, whichever
  479.        * gets us to the first pixel that falls inside the triangle.
  480.        *
  481.        * All parameters (z, red, etc.) as well as the buffer
  482.        * addresses for color and z have inner and outer step values,
  483.        * so that we can increment them appropriately.  This method
  484.        * eliminates the need to adjust parameters by creeping a
  485.        * sub-pixel amount into the triangle at each scanline.
  486.        */
  487.  
  488.       {
  489.          GLint subTriangle;
  490.          GLfixed fxLeftEdge = 0, fxRightEdge = 0;
  491.          GLfixed fdxLeftEdge = 0, fdxRightEdge = 0;
  492.          GLfixed fError = 0, fdError = 0;
  493. #ifdef PIXEL_ADDRESS
  494.          PIXEL_TYPE *pRow = NULL;
  495.          GLint dPRowOuter = 0, dPRowInner;  /* offset in bytes */
  496. #endif
  497. #ifdef INTERP_Z
  498. #  ifdef DEPTH_TYPE
  499.          struct gl_renderbuffer *zrb
  500.             = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
  501.          DEPTH_TYPE *zRow = NULL;
  502.          GLint dZRowOuter = 0, dZRowInner;  /* offset in bytes */
  503. #  endif
  504.          GLuint zLeft = 0;
  505.          GLfixed fdzOuter = 0, fdzInner;
  506. #endif
  507. #ifdef INTERP_RGB
  508.          GLint rLeft = 0, fdrOuter = 0, fdrInner;
  509.          GLint gLeft = 0, fdgOuter = 0, fdgInner;
  510.          GLint bLeft = 0, fdbOuter = 0, fdbInner;
  511. #endif
  512. #ifdef INTERP_ALPHA
  513.          GLint aLeft = 0, fdaOuter = 0, fdaInner;
  514. #endif
  515. #ifdef INTERP_INT_TEX
  516.          GLfixed sLeft=0, dsOuter=0, dsInner;
  517.          GLfixed tLeft=0, dtOuter=0, dtInner;
  518. #endif
  519. #ifdef INTERP_ATTRIBS
  520.          GLfloat wLeft = 0, dwOuter = 0, dwInner;
  521.          GLfloat attrLeft[FRAG_ATTRIB_MAX][4];
  522.          GLfloat daOuter[FRAG_ATTRIB_MAX][4], daInner[FRAG_ATTRIB_MAX][4];
  523. #endif
  524.  
  525.          for (subTriangle=0; subTriangle<=1; subTriangle++) {
  526.             EdgeT *eLeft, *eRight;
  527.             int setupLeft, setupRight;
  528.             int lines;
  529.  
  530.             if (subTriangle==0) {
  531.                /* bottom half */
  532.                if (scan_from_left_to_right) {
  533.                   eLeft = &eMaj;
  534.                   eRight = &eBot;
  535.                   lines = eRight->lines;
  536.                   setupLeft = 1;
  537.                   setupRight = 1;
  538.                }
  539.                else {
  540.                   eLeft = &eBot;
  541.                   eRight = &eMaj;
  542.                   lines = eLeft->lines;
  543.                   setupLeft = 1;
  544.                   setupRight = 1;
  545.                }
  546.             }
  547.             else {
  548.                /* top half */
  549.                if (scan_from_left_to_right) {
  550.                   eLeft = &eMaj;
  551.                   eRight = &eTop;
  552.                   lines = eRight->lines;
  553.                   setupLeft = 0;
  554.                   setupRight = 1;
  555.                }
  556.                else {
  557.                   eLeft = &eTop;
  558.                   eRight = &eMaj;
  559.                   lines = eLeft->lines;
  560.                   setupLeft = 1;
  561.                   setupRight = 0;
  562.                }
  563.                if (lines == 0)
  564.                   return;
  565.             }
  566.  
  567.             if (setupLeft && eLeft->lines > 0) {
  568.                const SWvertex *vLower = eLeft->v0;
  569.                const GLfixed fsy = eLeft->fsy;
  570.                const GLfixed fsx = eLeft->fsx;  /* no fractional part */
  571.                const GLfixed fx = FixedCeil(fsx);  /* no fractional part */
  572.                const GLfixed adjx = (GLfixed) (fx - eLeft->fx0); /* SCALED! */
  573.                const GLfixed adjy = (GLfixed) eLeft->adjy;      /* SCALED! */
  574.                GLint idxOuter;
  575.                GLfloat dxOuter;
  576.                GLfixed fdxOuter;
  577.  
  578.                fError = fx - fsx - FIXED_ONE;
  579.                fxLeftEdge = fsx - FIXED_EPSILON;
  580.                fdxLeftEdge = eLeft->fdxdy;
  581.                fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON);
  582.                fdError = fdxOuter - fdxLeftEdge + FIXED_ONE;
  583.                idxOuter = FixedToInt(fdxOuter);
  584.                dxOuter = (GLfloat) idxOuter;
  585.                span.y = FixedToInt(fsy);
  586.  
  587.                /* silence warnings on some compilers */
  588.                (void) dxOuter;
  589.                (void) adjx;
  590.                (void) adjy;
  591.                (void) vLower;
  592.  
  593. #ifdef PIXEL_ADDRESS
  594.                {
  595.                   pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(FixedToInt(fxLeftEdge), span.y);
  596.                   dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE);
  597.                   /* negative because Y=0 at bottom and increases upward */
  598.                }
  599. #endif
  600.                /*
  601.                 * Now we need the set of parameter (z, color, etc.) values at
  602.                 * the point (fx, fsy).  This gives us properly-sampled parameter
  603.                 * values that we can step from pixel to pixel.  Furthermore,
  604.                 * although we might have intermediate results that overflow
  605.                 * the normal parameter range when we step temporarily outside
  606.                 * the triangle, we shouldn't overflow or underflow for any
  607.                 * pixel that's actually inside the triangle.
  608.                 */
  609.  
  610. #ifdef INTERP_Z
  611.                {
  612.                   GLfloat z0 = vLower->attrib[FRAG_ATTRIB_WPOS][2];
  613.                   if (depthBits <= 16) {
  614.                      /* interpolate fixed-pt values */
  615.                      GLfloat tmp = (z0 * FIXED_SCALE
  616.                                     + span.attrStepX[FRAG_ATTRIB_WPOS][2] * adjx
  617.                                     + span.attrStepY[FRAG_ATTRIB_WPOS][2] * adjy) + FIXED_HALF;
  618.                      if (tmp < MAX_GLUINT / 2)
  619.                         zLeft = (GLfixed) tmp;
  620.                      else
  621.                         zLeft = MAX_GLUINT / 2;
  622.                      fdzOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_WPOS][2] +
  623.                                                    dxOuter * span.attrStepX[FRAG_ATTRIB_WPOS][2]);
  624.                   }
  625.                   else {
  626.                      /* interpolate depth values w/out scaling */
  627.                      zLeft = (GLuint) (z0 + span.attrStepX[FRAG_ATTRIB_WPOS][2] * FixedToFloat(adjx)
  628.                                           + span.attrStepY[FRAG_ATTRIB_WPOS][2] * FixedToFloat(adjy));
  629.                      fdzOuter = (GLint) (span.attrStepY[FRAG_ATTRIB_WPOS][2] +
  630.                                          dxOuter * span.attrStepX[FRAG_ATTRIB_WPOS][2]);
  631.                   }
  632. #  ifdef DEPTH_TYPE
  633.                   zRow = (DEPTH_TYPE *)
  634.                     zrb->GetPointer(ctx, zrb, FixedToInt(fxLeftEdge), span.y);
  635.                   dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE);
  636. #  endif
  637.                }
  638. #endif
  639. #ifdef INTERP_RGB
  640.                if (ctx->Light.ShadeModel == GL_SMOOTH) {
  641.                   rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP])
  642.                                   + span.attrStepX[FRAG_ATTRIB_COL0][0] * adjx
  643.                                   + span.attrStepY[FRAG_ATTRIB_COL0][0] * adjy) + FIXED_HALF;
  644.                   gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP])
  645.                                   + span.attrStepX[FRAG_ATTRIB_COL0][1] * adjx
  646.                                   + span.attrStepY[FRAG_ATTRIB_COL0][1] * adjy) + FIXED_HALF;
  647.                   bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP])
  648.                                   + span.attrStepX[FRAG_ATTRIB_COL0][2] * adjx
  649.                                   + span.attrStepY[FRAG_ATTRIB_COL0][2] * adjy) + FIXED_HALF;
  650.                   fdrOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][0]
  651.                                                 + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][0]);
  652.                   fdgOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][1]
  653.                                                 + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][1]);
  654.                   fdbOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][2]
  655.                                                 + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][2]);
  656. #  ifdef INTERP_ALPHA
  657.                   aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP])
  658.                                   + span.attrStepX[FRAG_ATTRIB_COL0][3] * adjx
  659.                                   + span.attrStepY[FRAG_ATTRIB_COL0][3] * adjy) + FIXED_HALF;
  660.                   fdaOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_COL0][3]
  661.                                                 + dxOuter * span.attrStepX[FRAG_ATTRIB_COL0][3]);
  662. #  endif
  663.                }
  664.                else {
  665.                   ASSERT(ctx->Light.ShadeModel == GL_FLAT);
  666.                   rLeft = ChanToFixed(v2->color[RCOMP]);
  667.                   gLeft = ChanToFixed(v2->color[GCOMP]);
  668.                   bLeft = ChanToFixed(v2->color[BCOMP]);
  669.                   fdrOuter = fdgOuter = fdbOuter = 0;
  670. #  ifdef INTERP_ALPHA
  671.                   aLeft = ChanToFixed(v2->color[ACOMP]);
  672.                   fdaOuter = 0;
  673. #  endif
  674.                }
  675. #endif /* INTERP_RGB */
  676.  
  677.  
  678. #ifdef INTERP_INT_TEX
  679.                {
  680.                   GLfloat s0, t0;
  681.                   s0 = vLower->attrib[FRAG_ATTRIB_TEX0][0] * S_SCALE;
  682.                   sLeft = (GLfixed)(s0 * FIXED_SCALE + span.attrStepX[FRAG_ATTRIB_TEX0][0] * adjx
  683.                                  + span.attrStepY[FRAG_ATTRIB_TEX0][0] * adjy) + FIXED_HALF;
  684.                   dsOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_TEX0][0]
  685.                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_TEX0][0]);
  686.  
  687.                   t0 = vLower->attrib[FRAG_ATTRIB_TEX0][1] * T_SCALE;
  688.                   tLeft = (GLfixed)(t0 * FIXED_SCALE + span.attrStepX[FRAG_ATTRIB_TEX0][1] * adjx
  689.                                  + span.attrStepY[FRAG_ATTRIB_TEX0][1] * adjy) + FIXED_HALF;
  690.                   dtOuter = SignedFloatToFixed(span.attrStepY[FRAG_ATTRIB_TEX0][1]
  691.                                                + dxOuter * span.attrStepX[FRAG_ATTRIB_TEX0][1]);
  692.                }
  693. #endif
  694. #ifdef INTERP_ATTRIBS
  695.                {
  696.                   const GLuint attr = FRAG_ATTRIB_WPOS;
  697.                   wLeft = vLower->attrib[FRAG_ATTRIB_WPOS][3]
  698.                         + (span.attrStepX[attr][3] * adjx
  699.                            + span.attrStepY[attr][3] * adjy) * (1.0F/FIXED_SCALE);
  700.                   dwOuter = span.attrStepY[attr][3] + dxOuter * span.attrStepX[attr][3];
  701.                }
  702.                ATTRIB_LOOP_BEGIN
  703.                   const GLfloat invW = vLower->attrib[FRAG_ATTRIB_WPOS][3];
  704.                   if (swrast->_InterpMode[attr] == GL_FLAT) {
  705.                      GLuint c;
  706.                      for (c = 0; c < 4; c++) {
  707.                         attrLeft[attr][c] = v2->attrib[attr][c] * invW;
  708.                         daOuter[attr][c] = 0.0;
  709.                      }
  710.                   }
  711.                   else {
  712.                      GLuint c;
  713.                      for (c = 0; c < 4; c++) {
  714.                         const GLfloat a = vLower->attrib[attr][c] * invW;
  715.                         attrLeft[attr][c] = a + (  span.attrStepX[attr][c] * adjx
  716.                                                  + span.attrStepY[attr][c] * adjy) * (1.0F/FIXED_SCALE);
  717.                         daOuter[attr][c] = span.attrStepY[attr][c] + dxOuter * span.attrStepX[attr][c];
  718.                      }
  719.                   }
  720.                ATTRIB_LOOP_END
  721. #endif
  722.             } /*if setupLeft*/
  723.  
  724.  
  725.             if (setupRight && eRight->lines>0) {
  726.                fxRightEdge = eRight->fsx - FIXED_EPSILON;
  727.                fdxRightEdge = eRight->fdxdy;
  728.             }
  729.  
  730.             if (lines==0) {
  731.                continue;
  732.             }
  733.  
  734.  
  735.             /* Rasterize setup */
  736. #ifdef PIXEL_ADDRESS
  737.             dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE);
  738. #endif
  739. #ifdef INTERP_Z
  740. #  ifdef DEPTH_TYPE
  741.             dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE);
  742. #  endif
  743.             fdzInner = fdzOuter + span.zStep;
  744. #endif
  745. #ifdef INTERP_RGB
  746.             fdrInner = fdrOuter + span.redStep;
  747.             fdgInner = fdgOuter + span.greenStep;
  748.             fdbInner = fdbOuter + span.blueStep;
  749. #endif
  750. #ifdef INTERP_ALPHA
  751.             fdaInner = fdaOuter + span.alphaStep;
  752. #endif
  753. #ifdef INTERP_INT_TEX
  754.             dsInner = dsOuter + span.intTexStep[0];
  755.             dtInner = dtOuter + span.intTexStep[1];
  756. #endif
  757. #ifdef INTERP_ATTRIBS
  758.             dwInner = dwOuter + span.attrStepX[FRAG_ATTRIB_WPOS][3];
  759.             ATTRIB_LOOP_BEGIN
  760.                GLuint c;
  761.                for (c = 0; c < 4; c++) {
  762.                   daInner[attr][c] = daOuter[attr][c] + span.attrStepX[attr][c];
  763.                }
  764.             ATTRIB_LOOP_END
  765. #endif
  766.  
  767.             while (lines > 0) {
  768.                /* initialize the span interpolants to the leftmost value */
  769.                /* ff = fixed-pt fragment */
  770.                const GLint right = FixedToInt(fxRightEdge);
  771.                span.x = FixedToInt(fxLeftEdge);
  772.                if (right <= span.x)
  773.                   span.end = 0;
  774.                else
  775.                   span.end = right - span.x;
  776.  
  777. #ifdef INTERP_Z
  778.                span.z = zLeft;
  779. #endif
  780. #ifdef INTERP_RGB
  781.                span.red = rLeft;
  782.                span.green = gLeft;
  783.                span.blue = bLeft;
  784. #endif
  785. #ifdef INTERP_ALPHA
  786.                span.alpha = aLeft;
  787. #endif
  788. #ifdef INTERP_INT_TEX
  789.                span.intTex[0] = sLeft;
  790.                span.intTex[1] = tLeft;
  791. #endif
  792.  
  793. #ifdef INTERP_ATTRIBS
  794.                span.attrStart[FRAG_ATTRIB_WPOS][3] = wLeft;
  795.                ATTRIB_LOOP_BEGIN
  796.                   GLuint c;
  797.                   for (c = 0; c < 4; c++) {
  798.                      span.attrStart[attr][c] = attrLeft[attr][c];
  799.                   }
  800.                ATTRIB_LOOP_END
  801. #endif
  802.  
  803.                /* This is where we actually generate fragments */
  804.                /* XXX the test for span.y > 0 _shouldn't_ be needed but
  805.                 * it fixes a problem on 64-bit Opterons (bug 4842).
  806.                 */
  807.                if (span.end > 0 && span.y >= 0) {
  808.                   const GLint len = span.end - 1;
  809.                   (void) len;
  810. #ifdef INTERP_RGB
  811.                   CLAMP_INTERPOLANT(red, redStep, len);
  812.                   CLAMP_INTERPOLANT(green, greenStep, len);
  813.                   CLAMP_INTERPOLANT(blue, blueStep, len);
  814. #endif
  815. #ifdef INTERP_ALPHA
  816.                   CLAMP_INTERPOLANT(alpha, alphaStep, len);
  817. #endif
  818.                   {
  819.                      RENDER_SPAN( span );
  820.                   }
  821.                }
  822.  
  823.                /*
  824.                 * Advance to the next scan line.  Compute the
  825.                 * new edge coordinates, and adjust the
  826.                 * pixel-center x coordinate so that it stays
  827.                 * on or inside the major edge.
  828.                 */
  829.                span.y++;
  830.                lines--;
  831.  
  832.                fxLeftEdge += fdxLeftEdge;
  833.                fxRightEdge += fdxRightEdge;
  834.  
  835.                fError += fdError;
  836.                if (fError >= 0) {
  837.                   fError -= FIXED_ONE;
  838.  
  839. #ifdef PIXEL_ADDRESS
  840.                   pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter);
  841. #endif
  842. #ifdef INTERP_Z
  843. #  ifdef DEPTH_TYPE
  844.                   zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter);
  845. #  endif
  846.                   zLeft += fdzOuter;
  847. #endif
  848. #ifdef INTERP_RGB
  849.                   rLeft += fdrOuter;
  850.                   gLeft += fdgOuter;
  851.                   bLeft += fdbOuter;
  852. #endif
  853. #ifdef INTERP_ALPHA
  854.                   aLeft += fdaOuter;
  855. #endif
  856. #ifdef INTERP_INT_TEX
  857.                   sLeft += dsOuter;
  858.                   tLeft += dtOuter;
  859. #endif
  860. #ifdef INTERP_ATTRIBS
  861.                   wLeft += dwOuter;
  862.                   ATTRIB_LOOP_BEGIN
  863.                      GLuint c;
  864.                      for (c = 0; c < 4; c++) {
  865.                         attrLeft[attr][c] += daOuter[attr][c];
  866.                      }
  867.                   ATTRIB_LOOP_END
  868. #endif
  869.                }
  870.                else {
  871. #ifdef PIXEL_ADDRESS
  872.                   pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner);
  873. #endif
  874. #ifdef INTERP_Z
  875. #  ifdef DEPTH_TYPE
  876.                   zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner);
  877. #  endif
  878.                   zLeft += fdzInner;
  879. #endif
  880. #ifdef INTERP_RGB
  881.                   rLeft += fdrInner;
  882.                   gLeft += fdgInner;
  883.                   bLeft += fdbInner;
  884. #endif
  885. #ifdef INTERP_ALPHA
  886.                   aLeft += fdaInner;
  887. #endif
  888. #ifdef INTERP_INT_TEX
  889.                   sLeft += dsInner;
  890.                   tLeft += dtInner;
  891. #endif
  892. #ifdef INTERP_ATTRIBS
  893.                   wLeft += dwInner;
  894.                   ATTRIB_LOOP_BEGIN
  895.                      GLuint c;
  896.                      for (c = 0; c < 4; c++) {
  897.                         attrLeft[attr][c] += daInner[attr][c];
  898.                      }
  899.                   ATTRIB_LOOP_END
  900. #endif
  901.                }
  902.             } /*while lines>0*/
  903.  
  904.          } /* for subTriangle */
  905.  
  906.       }
  907.    }
  908. }
  909.  
  910. #undef SETUP_CODE
  911. #undef RENDER_SPAN
  912.  
  913. #undef PIXEL_TYPE
  914. #undef BYTES_PER_ROW
  915. #undef PIXEL_ADDRESS
  916. #undef DEPTH_TYPE
  917.  
  918. #undef INTERP_Z
  919. #undef INTERP_RGB
  920. #undef INTERP_ALPHA
  921. #undef INTERP_INT_TEX
  922. #undef INTERP_ATTRIBS
  923.  
  924. #undef S_SCALE
  925. #undef T_SCALE
  926.  
  927. #undef FixedToDepth
  928.  
  929. #undef NAME
  930.