/* * Mesa 3-D graphics library * Version: 7.0 * * 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. */ /* * Triangle Rasterizer Template * * This file is #include'd to generate custom triangle rasterizers. * * The following macros may be defined to indicate what auxillary information * must be interpolated across the triangle: * INTERP_Z - if defined, interpolate integer Z values * INTERP_RGB - if defined, interpolate integer RGB values * INTERP_ALPHA - if defined, interpolate integer Alpha values * INTERP_INT_TEX - if defined, interpolate integer ST texcoords * (fast, simple 2-D texture mapping, without * perspective correction) * INTERP_ATTRIBS - if defined, interpolate arbitrary attribs (texcoords, * varying vars, etc) This also causes W to be * computed for perspective correction). * * When one can directly address pixels in the color buffer the following * macros can be defined and used to compute pixel addresses during * rasterization (see pRow): * PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint) * BYTES_PER_ROW - number of bytes per row in the color buffer * PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where * Y==0 at bottom of screen and increases upward. * * Similarly, for direct depth buffer access, this type is used for depth * buffer addressing (see zRow): * DEPTH_TYPE - either GLushort or GLuint * * Optionally, one may provide one-time setup code per triangle: * SETUP_CODE - code which is to be executed once per triangle * * The following macro MUST be defined: * RENDER_SPAN(span) - code to write a span of pixels. * * This code was designed for the origin to be in the lower-left corner. * * Inspired by triangle rasterizer code written by Allen Akin. Thanks Allen! * * * Some notes on rasterization accuracy: * * This code uses fixed point arithmetic (the GLfixed type) to iterate * over the triangle edges and interpolate ancillary data (such as Z, * color, secondary color, etc). The number of fractional bits in * GLfixed and the value of SUB_PIXEL_BITS has a direct bearing on the * accuracy of rasterization. * * If SUB_PIXEL_BITS=4 then we'll snap the vertices to the nearest * 1/16 of a pixel. If we're walking up a long, nearly vertical edge * (dx=1/16, dy=1024) we'll need 4 + 10 = 14 fractional bits in * GLfixed to walk the edge without error. If the maximum viewport * height is 4K pixels, then we'll need 4 + 12 = 16 fractional bits. * * Historically, Mesa has used 11 fractional bits in GLfixed, snaps * vertices to 1/16 pixel and allowed a maximum viewport height of 2K * pixels. 11 fractional bits is actually insufficient for accurately * rasterizing some triangles. More recently, the maximum viewport * height was increased to 4K pixels. Thus, Mesa should be using 16 * fractional bits in GLfixed. Unfortunately, there may be some issues * with setting FIXED_FRAC_BITS=16, such as multiplication overflow. * This will have to be examined in some detail... * * For now, if you find rasterization errors, particularly with tall, * sliver triangles, try increasing FIXED_FRAC_BITS and/or decreasing * SUB_PIXEL_BITS. */ /* * Some code we unfortunately need to prevent negative interpolated colors. */ #ifndef CLAMP_INTERPOLANT #define CLAMP_INTERPOLANT(CHANNEL, CHANNELSTEP, LEN) \ do { \ GLfixed endVal = span.CHANNEL + (LEN) * span.CHANNELSTEP; \ if (endVal < 0) { \ span.CHANNEL -= endVal; \ } \ if (span.CHANNEL < 0) { \ span.CHANNEL = 0; \ } \ } while (0) #endif static void NAME(struct gl_context *ctx, const SWvertex *v0, const SWvertex *v1, const SWvertex *v2 ) { typedef struct { const SWvertex *v0, *v1; /* Y(v0) < Y(v1) */ GLfloat dx; /* X(v1) - X(v0) */ GLfloat dy; /* Y(v1) - Y(v0) */ GLfloat dxdy; /* dx/dy */ GLfixed fdxdy; /* dx/dy in fixed-point */ GLfloat adjy; /* adjust from v[0]->fy to fsy, scaled */ GLfixed fsx; /* first sample point x coord */ GLfixed fsy; GLfixed fx0; /* fixed pt X of lower endpoint */ GLint lines; /* number of lines to be sampled on this edge */ } EdgeT; const SWcontext *swrast = SWRAST_CONTEXT(ctx); #ifdef INTERP_Z const GLint depthBits = ctx->DrawBuffer->Visual.depthBits; const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0; const GLfloat maxDepth = ctx->DrawBuffer->_DepthMaxF; #define FixedToDepth(F) ((F) >> fixedToDepthShift) #endif EdgeT eMaj, eTop, eBot; GLfloat oneOverArea; const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */ GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign; const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */ GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy; SWspan span; (void) swrast; INIT_SPAN(span, GL_POLYGON); span.y = 0; /* silence warnings */ #ifdef INTERP_Z (void) fixedToDepthShift; #endif /* printf("%s()\n", __FUNCTION__); printf(" %g, %g, %g\n", v0->attrib[VARYING_SLOT_POS][0], v0->attrib[VARYING_SLOT_POS][1], v0->attrib[VARYING_SLOT_POS][2]); printf(" %g, %g, %g\n", v1->attrib[VARYING_SLOT_POS][0], v1->attrib[VARYING_SLOT_POS][1], v1->attrib[VARYING_SLOT_POS][2]); printf(" %g, %g, %g\n", v2->attrib[VARYING_SLOT_POS][0], v2->attrib[VARYING_SLOT_POS][1], v2->attrib[VARYING_SLOT_POS][2]); */ /* Compute fixed point x,y coords w/ half-pixel offsets and snapping. * And find the order of the 3 vertices along the Y axis. */ { const GLfixed fy0 = FloatToFixed(v0->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; const GLfixed fy1 = FloatToFixed(v1->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; const GLfixed fy2 = FloatToFixed(v2->attrib[VARYING_SLOT_POS][1] - 0.5F) & snapMask; if (fy0 <= fy1) { if (fy1 <= fy2) { /* y0 <= y1 <= y2 */ vMin = v0; vMid = v1; vMax = v2; vMin_fy = fy0; vMid_fy = fy1; vMax_fy = fy2; } else if (fy2 <= fy0) { /* y2 <= y0 <= y1 */ vMin = v2; vMid = v0; vMax = v1; vMin_fy = fy2; vMid_fy = fy0; vMax_fy = fy1; } else { /* y0 <= y2 <= y1 */ vMin = v0; vMid = v2; vMax = v1; vMin_fy = fy0; vMid_fy = fy2; vMax_fy = fy1; bf = -bf; } } else { if (fy0 <= fy2) { /* y1 <= y0 <= y2 */ vMin = v1; vMid = v0; vMax = v2; vMin_fy = fy1; vMid_fy = fy0; vMax_fy = fy2; bf = -bf; } else if (fy2 <= fy1) { /* y2 <= y1 <= y0 */ vMin = v2; vMid = v1; vMax = v0; vMin_fy = fy2; vMid_fy = fy1; vMax_fy = fy0; bf = -bf; } else { /* y1 <= y2 <= y0 */ vMin = v1; vMid = v2; vMax = v0; vMin_fy = fy1; vMid_fy = fy2; vMax_fy = fy0; } } /* fixed point X coords */ vMin_fx = FloatToFixed(vMin->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; vMid_fx = FloatToFixed(vMid->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; vMax_fx = FloatToFixed(vMax->attrib[VARYING_SLOT_POS][0] + 0.5F) & snapMask; } /* vertex/edge relationship */ eMaj.v0 = vMin; eMaj.v1 = vMax; /*TODO: .v1's not needed */ eTop.v0 = vMid; eTop.v1 = vMax; eBot.v0 = vMin; eBot.v1 = vMid; /* compute deltas for each edge: vertex[upper] - vertex[lower] */ eMaj.dx = FixedToFloat(vMax_fx - vMin_fx); eMaj.dy = FixedToFloat(vMax_fy - vMin_fy); eTop.dx = FixedToFloat(vMax_fx - vMid_fx); eTop.dy = FixedToFloat(vMax_fy - vMid_fy); eBot.dx = FixedToFloat(vMid_fx - vMin_fx); eBot.dy = FixedToFloat(vMid_fy - vMin_fy); /* compute area, oneOverArea and perform backface culling */ { const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy; if (IS_INF_OR_NAN(area) || area == 0.0F) return; if (area * bf * swrast->_BackfaceCullSign < 0.0) return; oneOverArea = 1.0F / area; /* 0 = front, 1 = back */ span.facing = oneOverArea * bf > 0.0F; } /* Edge setup. For a triangle strip these could be reused... */ { eMaj.fsy = FixedCeil(vMin_fy); eMaj.lines = FixedToInt(FixedCeil(vMax_fy - eMaj.fsy)); if (eMaj.lines > 0) { eMaj.dxdy = eMaj.dx / eMaj.dy; eMaj.fdxdy = SignedFloatToFixed(eMaj.dxdy); eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */ eMaj.fx0 = vMin_fx; eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * eMaj.dxdy); } else { return; /*CULLED*/ } eTop.fsy = FixedCeil(vMid_fy); eTop.lines = FixedToInt(FixedCeil(vMax_fy - eTop.fsy)); if (eTop.lines > 0) { eTop.dxdy = eTop.dx / eTop.dy; eTop.fdxdy = SignedFloatToFixed(eTop.dxdy); eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */ eTop.fx0 = vMid_fx; eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * eTop.dxdy); } eBot.fsy = FixedCeil(vMin_fy); eBot.lines = FixedToInt(FixedCeil(vMid_fy - eBot.fsy)); if (eBot.lines > 0) { eBot.dxdy = eBot.dx / eBot.dy; eBot.fdxdy = SignedFloatToFixed(eBot.dxdy); eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */ eBot.fx0 = vMin_fx; eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * eBot.dxdy); } } /* * Conceptually, we view a triangle as two subtriangles * separated by a perfectly horizontal line. The edge that is * intersected by this line is one with maximal absolute dy; we * call it a ``major'' edge. The other two edges are the * ``top'' edge (for the upper subtriangle) and the ``bottom'' * edge (for the lower subtriangle). If either of these two * edges is horizontal or very close to horizontal, the * corresponding subtriangle might cover zero sample points; * we take care to handle such cases, for performance as well * as correctness. * * By stepping rasterization parameters along the major edge, * we can avoid recomputing them at the discontinuity where * the top and bottom edges meet. However, this forces us to * be able to scan both left-to-right and right-to-left. * Also, we must determine whether the major edge is at the * left or right side of the triangle. We do this by * computing the magnitude of the cross-product of the major * and top edges. Since this magnitude depends on the sine of * the angle between the two edges, its sign tells us whether * we turn to the left or to the right when travelling along * the major edge to the top edge, and from this we infer * whether the major edge is on the left or the right. * * Serendipitously, this cross-product magnitude is also a * value we need to compute the iteration parameter * derivatives for the triangle, and it can be used to perform * backface culling because its sign tells us whether the * triangle is clockwise or counterclockwise. In this code we * refer to it as ``area'' because it's also proportional to * the pixel area of the triangle. */ { GLint scan_from_left_to_right; /* true if scanning left-to-right */ /* * Execute user-supplied setup code */ #ifdef SETUP_CODE SETUP_CODE #endif scan_from_left_to_right = (oneOverArea < 0.0F); /* compute d?/dx and d?/dy derivatives */ #ifdef INTERP_Z span.interpMask |= SPAN_Z; { GLfloat eMaj_dz = vMax->attrib[VARYING_SLOT_POS][2] - vMin->attrib[VARYING_SLOT_POS][2]; GLfloat eBot_dz = vMid->attrib[VARYING_SLOT_POS][2] - vMin->attrib[VARYING_SLOT_POS][2]; span.attrStepX[VARYING_SLOT_POS][2] = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz); if (span.attrStepX[VARYING_SLOT_POS][2] > maxDepth || span.attrStepX[VARYING_SLOT_POS][2] < -maxDepth) { /* probably a sliver triangle */ span.attrStepX[VARYING_SLOT_POS][2] = 0.0; span.attrStepY[VARYING_SLOT_POS][2] = 0.0; } else { span.attrStepY[VARYING_SLOT_POS][2] = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx); } if (depthBits <= 16) span.zStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_POS][2]); else span.zStep = (GLint) span.attrStepX[VARYING_SLOT_POS][2]; } #endif #ifdef INTERP_RGB span.interpMask |= SPAN_RGBA; if (ctx->Light.ShadeModel == GL_SMOOTH) { GLfloat eMaj_dr = (GLfloat) (vMax->color[RCOMP] - vMin->color[RCOMP]); GLfloat eBot_dr = (GLfloat) (vMid->color[RCOMP] - vMin->color[RCOMP]); GLfloat eMaj_dg = (GLfloat) (vMax->color[GCOMP] - vMin->color[GCOMP]); GLfloat eBot_dg = (GLfloat) (vMid->color[GCOMP] - vMin->color[GCOMP]); GLfloat eMaj_db = (GLfloat) (vMax->color[BCOMP] - vMin->color[BCOMP]); GLfloat eBot_db = (GLfloat) (vMid->color[BCOMP] - vMin->color[BCOMP]); # ifdef INTERP_ALPHA GLfloat eMaj_da = (GLfloat) (vMax->color[ACOMP] - vMin->color[ACOMP]); GLfloat eBot_da = (GLfloat) (vMid->color[ACOMP] - vMin->color[ACOMP]); # endif span.attrStepX[VARYING_SLOT_COL0][0] = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr); span.attrStepY[VARYING_SLOT_COL0][0] = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx); span.attrStepX[VARYING_SLOT_COL0][1] = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg); span.attrStepY[VARYING_SLOT_COL0][1] = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx); span.attrStepX[VARYING_SLOT_COL0][2] = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db); span.attrStepY[VARYING_SLOT_COL0][2] = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx); span.redStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][0]); span.greenStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][1]); span.blueStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][2]); # ifdef INTERP_ALPHA span.attrStepX[VARYING_SLOT_COL0][3] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da); span.attrStepY[VARYING_SLOT_COL0][3] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx); span.alphaStep = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_COL0][3]); # endif /* INTERP_ALPHA */ } else { ASSERT(ctx->Light.ShadeModel == GL_FLAT); span.interpMask |= SPAN_FLAT; span.attrStepX[VARYING_SLOT_COL0][0] = span.attrStepY[VARYING_SLOT_COL0][0] = 0.0F; span.attrStepX[VARYING_SLOT_COL0][1] = span.attrStepY[VARYING_SLOT_COL0][1] = 0.0F; span.attrStepX[VARYING_SLOT_COL0][2] = span.attrStepY[VARYING_SLOT_COL0][2] = 0.0F; span.redStep = 0; span.greenStep = 0; span.blueStep = 0; # ifdef INTERP_ALPHA span.attrStepX[VARYING_SLOT_COL0][3] = span.attrStepY[VARYING_SLOT_COL0][3] = 0.0F; span.alphaStep = 0; # endif } #endif /* INTERP_RGB */ #ifdef INTERP_INT_TEX { GLfloat eMaj_ds = (vMax->attrib[VARYING_SLOT_TEX0][0] - vMin->attrib[VARYING_SLOT_TEX0][0]) * S_SCALE; GLfloat eBot_ds = (vMid->attrib[VARYING_SLOT_TEX0][0] - vMin->attrib[VARYING_SLOT_TEX0][0]) * S_SCALE; GLfloat eMaj_dt = (vMax->attrib[VARYING_SLOT_TEX0][1] - vMin->attrib[VARYING_SLOT_TEX0][1]) * T_SCALE; GLfloat eBot_dt = (vMid->attrib[VARYING_SLOT_TEX0][1] - vMin->attrib[VARYING_SLOT_TEX0][1]) * T_SCALE; span.attrStepX[VARYING_SLOT_TEX0][0] = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds); span.attrStepY[VARYING_SLOT_TEX0][0] = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx); span.attrStepX[VARYING_SLOT_TEX0][1] = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt); span.attrStepY[VARYING_SLOT_TEX0][1] = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx); span.intTexStep[0] = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_TEX0][0]); span.intTexStep[1] = SignedFloatToFixed(span.attrStepX[VARYING_SLOT_TEX0][1]); } #endif #ifdef INTERP_ATTRIBS { /* attrib[VARYING_SLOT_POS][3] is 1/W */ const GLfloat wMax = vMax->attrib[VARYING_SLOT_POS][3]; const GLfloat wMin = vMin->attrib[VARYING_SLOT_POS][3]; const GLfloat wMid = vMid->attrib[VARYING_SLOT_POS][3]; { const GLfloat eMaj_dw = wMax - wMin; const GLfloat eBot_dw = wMid - wMin; span.attrStepX[VARYING_SLOT_POS][3] = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw); span.attrStepY[VARYING_SLOT_POS][3] = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx); } ATTRIB_LOOP_BEGIN if (swrast->_InterpMode[attr] == GL_FLAT) { ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0); ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0); } else { GLuint c; for (c = 0; c < 4; c++) { GLfloat eMaj_da = vMax->attrib[attr][c] * wMax - vMin->attrib[attr][c] * wMin; GLfloat eBot_da = vMid->attrib[attr][c] * wMid - vMin->attrib[attr][c] * wMin; span.attrStepX[attr][c] = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da); span.attrStepY[attr][c] = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx); } } ATTRIB_LOOP_END } #endif /* * We always sample at pixel centers. However, we avoid * explicit half-pixel offsets in this code by incorporating * the proper offset in each of x and y during the * transformation to window coordinates. * * We also apply the usual rasterization rules to prevent * cracks and overlaps. A pixel is considered inside a * subtriangle if it meets all of four conditions: it is on or * to the right of the left edge, strictly to the left of the * right edge, on or below the top edge, and strictly above * the bottom edge. (Some edges may be degenerate.) * * The following discussion assumes left-to-right scanning * (that is, the major edge is on the left); the right-to-left * case is a straightforward variation. * * We start by finding the half-integral y coordinate that is * at or below the top of the triangle. This gives us the * first scan line that could possibly contain pixels that are * inside the triangle. * * Next we creep down the major edge until we reach that y, * and compute the corresponding x coordinate on the edge. * Then we find the half-integral x that lies on or just * inside the edge. This is the first pixel that might lie in * the interior of the triangle. (We won't know for sure * until we check the other edges.) * * As we rasterize the triangle, we'll step down the major * edge. For each step in y, we'll move an integer number * of steps in x. There are two possible x step sizes, which * we'll call the ``inner'' step (guaranteed to land on the * edge or inside it) and the ``outer'' step (guaranteed to * land on the edge or outside it). The inner and outer steps * differ by one. During rasterization we maintain an error * term that indicates our distance from the true edge, and * select either the inner step or the outer step, whichever * gets us to the first pixel that falls inside the triangle. * * All parameters (z, red, etc.) as well as the buffer * addresses for color and z have inner and outer step values, * so that we can increment them appropriately. This method * eliminates the need to adjust parameters by creeping a * sub-pixel amount into the triangle at each scanline. */ { GLint subTriangle; GLfixed fxLeftEdge = 0, fxRightEdge = 0; GLfixed fdxLeftEdge = 0, fdxRightEdge = 0; GLfixed fError = 0, fdError = 0; #ifdef PIXEL_ADDRESS PIXEL_TYPE *pRow = NULL; GLint dPRowOuter = 0, dPRowInner; /* offset in bytes */ #endif #ifdef INTERP_Z # ifdef DEPTH_TYPE struct gl_renderbuffer *zrb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer; DEPTH_TYPE *zRow = NULL; GLint dZRowOuter = 0, dZRowInner; /* offset in bytes */ # endif GLuint zLeft = 0; GLfixed fdzOuter = 0, fdzInner; #endif #ifdef INTERP_RGB GLint rLeft = 0, fdrOuter = 0, fdrInner; GLint gLeft = 0, fdgOuter = 0, fdgInner; GLint bLeft = 0, fdbOuter = 0, fdbInner; #endif #ifdef INTERP_ALPHA GLint aLeft = 0, fdaOuter = 0, fdaInner; #endif #ifdef INTERP_INT_TEX GLfixed sLeft=0, dsOuter=0, dsInner; GLfixed tLeft=0, dtOuter=0, dtInner; #endif #ifdef INTERP_ATTRIBS GLfloat wLeft = 0, dwOuter = 0, dwInner; GLfloat attrLeft[VARYING_SLOT_MAX][4]; GLfloat daOuter[VARYING_SLOT_MAX][4], daInner[VARYING_SLOT_MAX][4]; #endif for (subTriangle=0; subTriangle<=1; subTriangle++) { EdgeT *eLeft, *eRight; int setupLeft, setupRight; int lines; if (subTriangle==0) { /* bottom half */ if (scan_from_left_to_right) { eLeft = &eMaj; eRight = &eBot; lines = eRight->lines; setupLeft = 1; setupRight = 1; } else { eLeft = &eBot; eRight = &eMaj; lines = eLeft->lines; setupLeft = 1; setupRight = 1; } } else { /* top half */ if (scan_from_left_to_right) { eLeft = &eMaj; eRight = &eTop; lines = eRight->lines; setupLeft = 0; setupRight = 1; } else { eLeft = &eTop; eRight = &eMaj; lines = eLeft->lines; setupLeft = 1; setupRight = 0; } if (lines == 0) return; } if (setupLeft && eLeft->lines > 0) { const SWvertex *vLower = eLeft->v0; const GLfixed fsy = eLeft->fsy; const GLfixed fsx = eLeft->fsx; /* no fractional part */ const GLfixed fx = FixedCeil(fsx); /* no fractional part */ const GLfixed adjx = (GLfixed) (fx - eLeft->fx0); /* SCALED! */ const GLfixed adjy = (GLfixed) eLeft->adjy; /* SCALED! */ GLint idxOuter; GLfloat dxOuter; GLfixed fdxOuter; fError = fx - fsx - FIXED_ONE; fxLeftEdge = fsx - FIXED_EPSILON; fdxLeftEdge = eLeft->fdxdy; fdxOuter = FixedFloor(fdxLeftEdge - FIXED_EPSILON); fdError = fdxOuter - fdxLeftEdge + FIXED_ONE; idxOuter = FixedToInt(fdxOuter); dxOuter = (GLfloat) idxOuter; span.y = FixedToInt(fsy); /* silence warnings on some compilers */ (void) dxOuter; (void) adjx; (void) adjy; (void) vLower; #ifdef PIXEL_ADDRESS { pRow = (PIXEL_TYPE *) PIXEL_ADDRESS(FixedToInt(fxLeftEdge), span.y); dPRowOuter = -((int)BYTES_PER_ROW) + idxOuter * sizeof(PIXEL_TYPE); /* negative because Y=0 at bottom and increases upward */ } #endif /* * Now we need the set of parameter (z, color, etc.) values at * the point (fx, fsy). This gives us properly-sampled parameter * values that we can step from pixel to pixel. Furthermore, * although we might have intermediate results that overflow * the normal parameter range when we step temporarily outside * the triangle, we shouldn't overflow or underflow for any * pixel that's actually inside the triangle. */ #ifdef INTERP_Z { GLfloat z0 = vLower->attrib[VARYING_SLOT_POS][2]; if (depthBits <= 16) { /* interpolate fixed-pt values */ GLfloat tmp = (z0 * FIXED_SCALE + span.attrStepX[VARYING_SLOT_POS][2] * adjx + span.attrStepY[VARYING_SLOT_POS][2] * adjy) + FIXED_HALF; if (tmp < MAX_GLUINT / 2) zLeft = (GLfixed) tmp; else zLeft = MAX_GLUINT / 2; fdzOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_POS][2] + dxOuter * span.attrStepX[VARYING_SLOT_POS][2]); } else { /* interpolate depth values w/out scaling */ zLeft = (GLuint) (z0 + span.attrStepX[VARYING_SLOT_POS][2] * FixedToFloat(adjx) + span.attrStepY[VARYING_SLOT_POS][2] * FixedToFloat(adjy)); fdzOuter = (GLint) (span.attrStepY[VARYING_SLOT_POS][2] + dxOuter * span.attrStepX[VARYING_SLOT_POS][2]); } # ifdef DEPTH_TYPE zRow = (DEPTH_TYPE *) _swrast_pixel_address(zrb, FixedToInt(fxLeftEdge), span.y); dZRowOuter = (ctx->DrawBuffer->Width + idxOuter) * sizeof(DEPTH_TYPE); # endif } #endif #ifdef INTERP_RGB if (ctx->Light.ShadeModel == GL_SMOOTH) { rLeft = (GLint)(ChanToFixed(vLower->color[RCOMP]) + span.attrStepX[VARYING_SLOT_COL0][0] * adjx + span.attrStepY[VARYING_SLOT_COL0][0] * adjy) + FIXED_HALF; gLeft = (GLint)(ChanToFixed(vLower->color[GCOMP]) + span.attrStepX[VARYING_SLOT_COL0][1] * adjx + span.attrStepY[VARYING_SLOT_COL0][1] * adjy) + FIXED_HALF; bLeft = (GLint)(ChanToFixed(vLower->color[BCOMP]) + span.attrStepX[VARYING_SLOT_COL0][2] * adjx + span.attrStepY[VARYING_SLOT_COL0][2] * adjy) + FIXED_HALF; fdrOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][0] + dxOuter * span.attrStepX[VARYING_SLOT_COL0][0]); fdgOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][1] + dxOuter * span.attrStepX[VARYING_SLOT_COL0][1]); fdbOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][2] + dxOuter * span.attrStepX[VARYING_SLOT_COL0][2]); # ifdef INTERP_ALPHA aLeft = (GLint)(ChanToFixed(vLower->color[ACOMP]) + span.attrStepX[VARYING_SLOT_COL0][3] * adjx + span.attrStepY[VARYING_SLOT_COL0][3] * adjy) + FIXED_HALF; fdaOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_COL0][3] + dxOuter * span.attrStepX[VARYING_SLOT_COL0][3]); # endif } else { ASSERT(ctx->Light.ShadeModel == GL_FLAT); rLeft = ChanToFixed(v2->color[RCOMP]); gLeft = ChanToFixed(v2->color[GCOMP]); bLeft = ChanToFixed(v2->color[BCOMP]); fdrOuter = fdgOuter = fdbOuter = 0; # ifdef INTERP_ALPHA aLeft = ChanToFixed(v2->color[ACOMP]); fdaOuter = 0; # endif } #endif /* INTERP_RGB */ #ifdef INTERP_INT_TEX { GLfloat s0, t0; s0 = vLower->attrib[VARYING_SLOT_TEX0][0] * S_SCALE; sLeft = (GLfixed)(s0 * FIXED_SCALE + span.attrStepX[VARYING_SLOT_TEX0][0] * adjx + span.attrStepY[VARYING_SLOT_TEX0][0] * adjy) + FIXED_HALF; dsOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_TEX0][0] + dxOuter * span.attrStepX[VARYING_SLOT_TEX0][0]); t0 = vLower->attrib[VARYING_SLOT_TEX0][1] * T_SCALE; tLeft = (GLfixed)(t0 * FIXED_SCALE + span.attrStepX[VARYING_SLOT_TEX0][1] * adjx + span.attrStepY[VARYING_SLOT_TEX0][1] * adjy) + FIXED_HALF; dtOuter = SignedFloatToFixed(span.attrStepY[VARYING_SLOT_TEX0][1] + dxOuter * span.attrStepX[VARYING_SLOT_TEX0][1]); } #endif #ifdef INTERP_ATTRIBS { const GLuint attr = VARYING_SLOT_POS; wLeft = vLower->attrib[VARYING_SLOT_POS][3] + (span.attrStepX[attr][3] * adjx + span.attrStepY[attr][3] * adjy) * (1.0F/FIXED_SCALE); dwOuter = span.attrStepY[attr][3] + dxOuter * span.attrStepX[attr][3]; } ATTRIB_LOOP_BEGIN const GLfloat invW = vLower->attrib[VARYING_SLOT_POS][3]; if (swrast->_InterpMode[attr] == GL_FLAT) { GLuint c; for (c = 0; c < 4; c++) { attrLeft[attr][c] = v2->attrib[attr][c] * invW; daOuter[attr][c] = 0.0; } } else { GLuint c; for (c = 0; c < 4; c++) { const GLfloat a = vLower->attrib[attr][c] * invW; attrLeft[attr][c] = a + ( span.attrStepX[attr][c] * adjx + span.attrStepY[attr][c] * adjy) * (1.0F/FIXED_SCALE); daOuter[attr][c] = span.attrStepY[attr][c] + dxOuter * span.attrStepX[attr][c]; } } ATTRIB_LOOP_END #endif } /*if setupLeft*/ if (setupRight && eRight->lines>0) { fxRightEdge = eRight->fsx - FIXED_EPSILON; fdxRightEdge = eRight->fdxdy; } if (lines==0) { continue; } /* Rasterize setup */ #ifdef PIXEL_ADDRESS dPRowInner = dPRowOuter + sizeof(PIXEL_TYPE); #endif #ifdef INTERP_Z # ifdef DEPTH_TYPE dZRowInner = dZRowOuter + sizeof(DEPTH_TYPE); # endif fdzInner = fdzOuter + span.zStep; #endif #ifdef INTERP_RGB fdrInner = fdrOuter + span.redStep; fdgInner = fdgOuter + span.greenStep; fdbInner = fdbOuter + span.blueStep; #endif #ifdef INTERP_ALPHA fdaInner = fdaOuter + span.alphaStep; #endif #ifdef INTERP_INT_TEX dsInner = dsOuter + span.intTexStep[0]; dtInner = dtOuter + span.intTexStep[1]; #endif #ifdef INTERP_ATTRIBS dwInner = dwOuter + span.attrStepX[VARYING_SLOT_POS][3]; ATTRIB_LOOP_BEGIN GLuint c; for (c = 0; c < 4; c++) { daInner[attr][c] = daOuter[attr][c] + span.attrStepX[attr][c]; } ATTRIB_LOOP_END #endif while (lines > 0) { /* initialize the span interpolants to the leftmost value */ /* ff = fixed-pt fragment */ const GLint right = FixedToInt(fxRightEdge); span.x = FixedToInt(fxLeftEdge); if (right <= span.x) span.end = 0; else span.end = right - span.x; #ifdef INTERP_Z span.z = zLeft; #endif #ifdef INTERP_RGB span.red = rLeft; span.green = gLeft; span.blue = bLeft; #endif #ifdef INTERP_ALPHA span.alpha = aLeft; #endif #ifdef INTERP_INT_TEX span.intTex[0] = sLeft; span.intTex[1] = tLeft; #endif #ifdef INTERP_ATTRIBS span.attrStart[VARYING_SLOT_POS][3] = wLeft; ATTRIB_LOOP_BEGIN GLuint c; for (c = 0; c < 4; c++) { span.attrStart[attr][c] = attrLeft[attr][c]; } ATTRIB_LOOP_END #endif /* This is where we actually generate fragments */ /* XXX the test for span.y > 0 _shouldn't_ be needed but * it fixes a problem on 64-bit Opterons (bug 4842). */ if (span.end > 0 && span.y >= 0) { const GLint len = span.end - 1; (void) len; #ifdef INTERP_RGB CLAMP_INTERPOLANT(red, redStep, len); CLAMP_INTERPOLANT(green, greenStep, len); CLAMP_INTERPOLANT(blue, blueStep, len); #endif #ifdef INTERP_ALPHA CLAMP_INTERPOLANT(alpha, alphaStep, len); #endif { RENDER_SPAN( span ); } } /* * Advance to the next scan line. Compute the * new edge coordinates, and adjust the * pixel-center x coordinate so that it stays * on or inside the major edge. */ span.y++; lines--; fxLeftEdge += fdxLeftEdge; fxRightEdge += fdxRightEdge; fError += fdError; if (fError >= 0) { fError -= FIXED_ONE; #ifdef PIXEL_ADDRESS pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowOuter); #endif #ifdef INTERP_Z # ifdef DEPTH_TYPE zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowOuter); # endif zLeft += fdzOuter; #endif #ifdef INTERP_RGB rLeft += fdrOuter; gLeft += fdgOuter; bLeft += fdbOuter; #endif #ifdef INTERP_ALPHA aLeft += fdaOuter; #endif #ifdef INTERP_INT_TEX sLeft += dsOuter; tLeft += dtOuter; #endif #ifdef INTERP_ATTRIBS wLeft += dwOuter; ATTRIB_LOOP_BEGIN GLuint c; for (c = 0; c < 4; c++) { attrLeft[attr][c] += daOuter[attr][c]; } ATTRIB_LOOP_END #endif } else { #ifdef PIXEL_ADDRESS pRow = (PIXEL_TYPE *) ((GLubyte *) pRow + dPRowInner); #endif #ifdef INTERP_Z # ifdef DEPTH_TYPE zRow = (DEPTH_TYPE *) ((GLubyte *) zRow + dZRowInner); # endif zLeft += fdzInner; #endif #ifdef INTERP_RGB rLeft += fdrInner; gLeft += fdgInner; bLeft += fdbInner; #endif #ifdef INTERP_ALPHA aLeft += fdaInner; #endif #ifdef INTERP_INT_TEX sLeft += dsInner; tLeft += dtInner; #endif #ifdef INTERP_ATTRIBS wLeft += dwInner; ATTRIB_LOOP_BEGIN GLuint c; for (c = 0; c < 4; c++) { attrLeft[attr][c] += daInner[attr][c]; } ATTRIB_LOOP_END #endif } } /*while lines>0*/ } /* for subTriangle */ } } } #undef SETUP_CODE #undef RENDER_SPAN #undef PIXEL_TYPE #undef BYTES_PER_ROW #undef PIXEL_ADDRESS #undef DEPTH_TYPE #undef INTERP_Z #undef INTERP_RGB #undef INTERP_ALPHA #undef INTERP_INT_TEX #undef INTERP_ATTRIBS #undef S_SCALE #undef T_SCALE #undef FixedToDepth #undef NAME