/* $Id: tritemp.h,v 1.17 1998/01/16 03:46:07 brianp Exp $ */ /* * Mesa 3-D graphics library * Version: 2.6 * Copyright (C) 1995-1997 Brian Paul * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the Free * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* * $Log: tritemp.h,v $ * Revision 1.17 1998/01/16 03:46:07 brianp * fixed a few Windows compilation warnings (Theodore Jump) * * Revision 1.16 1997/09/18 01:08:10 brianp * fixed S_SCALE / T_SCALE mix-up * * Revision 1.15 1997/08/22 01:53:03 brianp * another attempt at fixing under/overflow errors * * Revision 1.14 1997/08/13 02:10:13 brianp * added code to prevent over/underflow (Guido Jansen, Magnus Lundin) * * Revision 1.13 1997/06/20 02:52:49 brianp * changed color components from GLfixed to GLubyte * * Revision 1.12 1997/03/14 00:25:02 brianp * fixed unitialized memory read, contributed by Tom Schmidt * * Revision 1.11 1997/02/09 18:51:10 brianp * fixed typo in texture R interpolation code * * Revision 1.10 1996/12/20 23:12:23 brianp * another attempt at preventing color interpolation over/underflow * * Revision 1.9 1996/12/18 20:38:25 brianp * commented out unused zp declaration * * Revision 1.8 1996/12/12 22:37:49 brianp * projective textures didn't work right * * Revision 1.7 1996/11/02 06:17:37 brianp * fixed some float/int roundoff and over/underflow errors (hopefully) * * Revision 1.6 1996/10/01 04:13:09 brianp * fixed Z interpolation for >16-bit depth buffer * added color underflow error check * * Revision 1.5 1996/09/27 01:32:59 brianp * removed unused variables * * Revision 1.4 1996/09/18 01:03:43 brianp * tightened threshold for culling by area * * Revision 1.3 1996/09/15 14:19:16 brianp * now use GLframebuffer and GLvisual * * Revision 1.2 1996/09/14 06:41:38 brianp * perspective correct texture code wasn't sub-pixel accurate (Doug Rabson) * * Revision 1.1 1996/09/13 01:38:16 brianp * Initial revision * */ /* * 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 interplated across the triangle: * INTERP_Z - if defined, interpolate Z values * INTERP_RGB - if defined, interpolate RGB values * INTERP_ALPHA - if defined, interpolate Alpha values * INTERP_INDEX - if defined, interpolate color index values * INTERP_ST - if defined, interpolate integer ST texcoords * (fast, simple 2-D texture mapping) * INTERP_STW - if defined, interpolate float ST texcoords and W * (2-D texture maps with perspective correction) * INTERP_UV - if defined, interpolate float UV texcoords too * (for 3-D, 4-D? texture maps) * * 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. * * 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: * INNER_LOOP(LEFT,RIGHT,Y) - code to write a span of pixels. * Something like: * * for (x=LEFT; xfy to fsy, scaled */ GLint lines; /* number of lines to be sampled on this edge */ GLfixed fx0; /* fixed pt X of lower endpoint */ } EdgeT; struct vertex_buffer *VB = ctx->VB; EdgeT eMaj, eTop, eBot; GLfloat oneOverArea; int vMin, vMid, vMax; /* vertex indexes: Y(vMin)<=Y(vMid)<=Y(vMax) */ /* find the order of the 3 vertices along the Y axis */ { GLfloat y0 = VB->Win[v0][1]; GLfloat y1 = VB->Win[v1][1]; GLfloat y2 = VB->Win[v2][1]; if (y0<=y1) { if (y1<=y2) { vMin = v0; vMid = v1; vMax = v2; /* y0<=y1<=y2 */ } else if (y2<=y0) { vMin = v2; vMid = v0; vMax = v1; /* y2<=y0<=y1 */ } else { vMin = v0; vMid = v2; vMax = v1; /* y0<=y2<=y1 */ } } else { if (y0<=y2) { vMin = v1; vMid = v0; vMax = v2; /* y1<=y0<=y2 */ } else if (y2<=y1) { vMin = v2; vMid = v1; vMax = v0; /* y2<=y1<=y0 */ } else { vMin = v1; vMid = v2; vMax = v0; /* y1<=y2<=y0 */ } } } /* 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[v1] - vertex[v0] */ eMaj.dx = VB->Win[vMax][0] - VB->Win[vMin][0]; eMaj.dy = VB->Win[vMax][1] - VB->Win[vMin][1]; eTop.dx = VB->Win[vMax][0] - VB->Win[vMid][0]; eTop.dy = VB->Win[vMax][1] - VB->Win[vMid][1]; eBot.dx = VB->Win[vMid][0] - VB->Win[vMin][0]; eBot.dy = VB->Win[vMid][1] - VB->Win[vMin][1]; /* compute oneOverArea */ { GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy; if (area>-0.05f && area<0.05f) { return; /* very small; CULLED */ } oneOverArea = 1.0F / area; } /* Edge setup. For a triangle strip these could be reused... */ { /* fixed point Y coordinates */ GLfixed vMin_fx = FloatToFixed(VB->Win[vMin][0] + 0.5F); GLfixed vMin_fy = FloatToFixed(VB->Win[vMin][1] - 0.5F); GLfixed vMid_fx = FloatToFixed(VB->Win[vMid][0] + 0.5F); GLfixed vMid_fy = FloatToFixed(VB->Win[vMid][1] - 0.5F); GLfixed vMax_fy = FloatToFixed(VB->Win[vMax][1] - 0.5F); eMaj.fsy = FixedCeil(vMin_fy); eMaj.lines = FixedToInt(vMax_fy + FIXED_ONE - FIXED_EPSILON - eMaj.fsy); if (eMaj.lines > 0) { GLfloat dxdy = eMaj.dx / eMaj.dy; eMaj.fdxdy = SignedFloatToFixed(dxdy); eMaj.adjy = (GLfloat) (eMaj.fsy - vMin_fy); /* SCALED! */ eMaj.fx0 = vMin_fx; eMaj.fsx = eMaj.fx0 + (GLfixed) (eMaj.adjy * dxdy); } else { return; /*CULLED*/ } eTop.fsy = FixedCeil(vMid_fy); eTop.lines = FixedToInt(vMax_fy + FIXED_ONE - FIXED_EPSILON - eTop.fsy); if (eTop.lines > 0) { GLfloat dxdy = eTop.dx / eTop.dy; eTop.fdxdy = SignedFloatToFixed(dxdy); eTop.adjy = (GLfloat) (eTop.fsy - vMid_fy); /* SCALED! */ eTop.fx0 = vMid_fx; eTop.fsx = eTop.fx0 + (GLfixed) (eTop.adjy * dxdy); } eBot.fsy = FixedCeil(vMin_fy); eBot.lines = FixedToInt(vMid_fy + FIXED_ONE - FIXED_EPSILON - eBot.fsy); if (eBot.lines > 0) { GLfloat dxdy = eBot.dx / eBot.dy; eBot.fdxdy = SignedFloatToFixed(dxdy); eBot.adjy = (GLfloat) (eBot.fsy - vMin_fy); /* SCALED! */ eBot.fx0 = vMin_fx; eBot.fsx = eBot.fx0 + (GLfixed) (eBot.adjy * 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 ltor; /* true if scanning left-to-right */ #if INTERP_Z GLfloat dzdx, dzdy; GLfixed fdzdx; #endif #if INTERP_RGB GLfloat drdx, drdy; GLfixed fdrdx; GLfloat dgdx, dgdy; GLfixed fdgdx; GLfloat dbdx, dbdy; GLfixed fdbdx; #endif #if INTERP_ALPHA GLfloat dadx, dady; GLfixed fdadx; #endif #if INTERP_INDEX GLfloat didx, didy; GLfixed fdidx; #endif #if INTERP_ST GLfloat dsdx, dsdy; GLfixed fdsdx; GLfloat dtdx, dtdy; GLfixed fdtdx; #endif #if INTERP_STW GLfloat dsdx, dsdy; GLfloat dtdx, dtdy; GLfloat dwdx, dwdy; #endif #if INTERP_UV GLfloat dudx, dudy; GLfloat dvdx, dvdy; #endif /* * Execute user-supplied setup code */ #ifdef SETUP_CODE SETUP_CODE #endif ltor = (oneOverArea < 0.0F); /* compute d?/dx and d?/dy derivatives */ #if INTERP_Z { GLfloat eMaj_dz, eBot_dz; eMaj_dz = VB->Win[vMax][2] - VB->Win[vMin][2]; eBot_dz = VB->Win[vMid][2] - VB->Win[vMin][2]; dzdx = oneOverArea * (eMaj_dz * eBot.dy - eMaj.dy * eBot_dz); if (dzdx>DEPTH_SCALE || dzdx<-DEPTH_SCALE) { /* probably a sliver triangle */ dzdx = 0.0; dzdy = 0.0; } else { dzdy = oneOverArea * (eMaj.dx * eBot_dz - eMaj_dz * eBot.dx); } fdzdx = (GLint) dzdx; } #endif #if INTERP_RGB { GLfloat eMaj_dr, eBot_dr; eMaj_dr = (GLint) VB->Color[vMax][0] - (GLint) VB->Color[vMin][0]; eBot_dr = (GLint) VB->Color[vMid][0] - (GLint) VB->Color[vMin][0]; drdx = oneOverArea * (eMaj_dr * eBot.dy - eMaj.dy * eBot_dr); fdrdx = SignedFloatToFixed(drdx); drdy = oneOverArea * (eMaj.dx * eBot_dr - eMaj_dr * eBot.dx); } { GLfloat eMaj_dg, eBot_dg; eMaj_dg = (GLint) VB->Color[vMax][1] - (GLint) VB->Color[vMin][1]; eBot_dg = (GLint) VB->Color[vMid][1] - (GLint) VB->Color[vMin][1]; dgdx = oneOverArea * (eMaj_dg * eBot.dy - eMaj.dy * eBot_dg); fdgdx = SignedFloatToFixed(dgdx); dgdy = oneOverArea * (eMaj.dx * eBot_dg - eMaj_dg * eBot.dx); } { GLfloat eMaj_db, eBot_db; eMaj_db = (GLint) VB->Color[vMax][2] - (GLint) VB->Color[vMin][2]; eBot_db = (GLint) VB->Color[vMid][2] - (GLint) VB->Color[vMin][2]; dbdx = oneOverArea * (eMaj_db * eBot.dy - eMaj.dy * eBot_db); fdbdx = SignedFloatToFixed(dbdx); dbdy = oneOverArea * (eMaj.dx * eBot_db - eMaj_db * eBot.dx); } #endif #if INTERP_ALPHA { GLfloat eMaj_da, eBot_da; eMaj_da = (GLint) VB->Color[vMax][3] - (GLint) VB->Color[vMin][3]; eBot_da = (GLint) VB->Color[vMid][3] - (GLint) VB->Color[vMin][3]; dadx = oneOverArea * (eMaj_da * eBot.dy - eMaj.dy * eBot_da); fdadx = SignedFloatToFixed(dadx); dady = oneOverArea * (eMaj.dx * eBot_da - eMaj_da * eBot.dx); } #endif #if INTERP_INDEX { GLfloat eMaj_di, eBot_di; eMaj_di = (GLint) VB->Index[vMax] - (GLint) VB->Index[vMin]; eBot_di = (GLint) VB->Index[vMid] - (GLint) VB->Index[vMin]; didx = oneOverArea * (eMaj_di * eBot.dy - eMaj.dy * eBot_di); fdidx = SignedFloatToFixed(didx); didy = oneOverArea * (eMaj.dx * eBot_di - eMaj_di * eBot.dx); } #endif #if INTERP_ST { GLfloat eMaj_ds, eBot_ds; eMaj_ds = (VB->TexCoord[vMax][0] - VB->TexCoord[vMin][0]) * S_SCALE; eBot_ds = (VB->TexCoord[vMid][0] - VB->TexCoord[vMin][0]) * S_SCALE; dsdx = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds); fdsdx = SignedFloatToFixed(dsdx); dsdy = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx); } { GLfloat eMaj_dt, eBot_dt; eMaj_dt = (VB->TexCoord[vMax][1] - VB->TexCoord[vMin][1]) * T_SCALE; eBot_dt = (VB->TexCoord[vMid][1] - VB->TexCoord[vMin][1]) * T_SCALE; dtdx = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt); fdtdx = SignedFloatToFixed(dtdx); dtdy = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx); } #endif #if INTERP_STW { GLfloat wMax = 1.0F / VB->Clip[vMax][3]; GLfloat wMin = 1.0F / VB->Clip[vMin][3]; GLfloat wMid = 1.0F / VB->Clip[vMid][3]; GLfloat eMaj_dw, eBot_dw; GLfloat eMaj_ds, eBot_ds; GLfloat eMaj_dt, eBot_dt; #if INTERP_UV GLfloat eMaj_du, eBot_du; GLfloat eMaj_dv, eBot_dv; #endif eMaj_dw = wMax - wMin; eBot_dw = wMid - wMin; dwdx = oneOverArea * (eMaj_dw * eBot.dy - eMaj.dy * eBot_dw); dwdy = oneOverArea * (eMaj.dx * eBot_dw - eMaj_dw * eBot.dx); eMaj_ds = VB->TexCoord[vMax][0]*wMax - VB->TexCoord[vMin][0]*wMin; eBot_ds = VB->TexCoord[vMid][0]*wMid - VB->TexCoord[vMin][0]*wMin; dsdx = oneOverArea * (eMaj_ds * eBot.dy - eMaj.dy * eBot_ds); dsdy = oneOverArea * (eMaj.dx * eBot_ds - eMaj_ds * eBot.dx); eMaj_dt = VB->TexCoord[vMax][1]*wMax - VB->TexCoord[vMin][1]*wMin; eBot_dt = VB->TexCoord[vMid][1]*wMid - VB->TexCoord[vMin][1]*wMin; dtdx = oneOverArea * (eMaj_dt * eBot.dy - eMaj.dy * eBot_dt); dtdy = oneOverArea * (eMaj.dx * eBot_dt - eMaj_dt * eBot.dx); #if INTERP_UV eMaj_du = VB->TexCoord[vMax][2]*wMax - VB->TexCoord[vMin][2]*wMin; eBot_du = VB->TexCoord[vMid][2]*wMid - VB->TexCoord[vMin][2]*wMin; dudx = oneOverArea * (eMaj_du * eBot.dy - eMaj.dy * eBot_du); dudy = oneOverArea * (eMaj.dx * eBot_du - eMaj_du * eBot.dx); /* Note: don't divide V component by W */ eMaj_dv = VB->TexCoord[vMax][3] - VB->TexCoord[vMin][3]; eBot_dv = VB->TexCoord[vMid][3] - VB->TexCoord[vMin][3]; dvdx = oneOverArea * (eMaj_dv * eBot.dy - eMaj.dy * eBot_dv); dvdy = oneOverArea * (eMaj.dx * eBot_dv - eMaj_dv * eBot.dx); #endif } #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. */ { int subTriangle; GLfixed fx, fxLeftEdge, fxRightEdge, fdxLeftEdge, fdxRightEdge; GLfixed fdxOuter; int idxOuter; float dxOuter; GLfixed fError, fdError; float adjx, adjy; GLfixed fy; int iy; #ifdef PIXEL_ADDRESS PIXEL_TYPE *pRow; int dPRowOuter, dPRowInner; /* offset in bytes */ #endif #if INTERP_Z GLdepth *zRow; int dZRowOuter, dZRowInner; /* offset in bytes */ GLfixed fz, fdzOuter, fdzInner; #endif #if INTERP_RGB GLfixed fr, fdrOuter, fdrInner; GLfixed fg, fdgOuter, fdgInner; GLfixed fb, fdbOuter, fdbInner; #endif #if INTERP_ALPHA GLfixed fa, fdaOuter, fdaInner; #endif #if INTERP_INDEX GLfixed fi, fdiOuter, fdiInner; #endif #if INTERP_ST GLfixed fs, fdsOuter, fdsInner; GLfixed ft, fdtOuter, fdtInner; #endif #if INTERP_STW GLfloat sLeft, dsOuter, dsInner; GLfloat tLeft, dtOuter, dtInner; GLfloat wLeft, dwOuter, dwInner; #endif #if INTERP_UV GLfloat uLeft, duOuter, duInner; GLfloat vLeft, dvOuter, dvInner; #endif for (subTriangle=0; subTriangle<=1; subTriangle++) { EdgeT *eLeft, *eRight; int setupLeft, setupRight; int lines; if (subTriangle==0) { /* bottom half */ if (ltor) { 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 (ltor) { 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) { GLint vLower; GLfixed fsx = eLeft->fsx; fx = FixedCeil(fsx); 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 = (float) idxOuter; fy = eLeft->fsy; iy = FixedToInt(fy); adjx = (float)(fx - eLeft->fx0); /* SCALED! */ adjy = eLeft->adjy; /* SCALED! */ vLower = eLeft->v0; #ifdef PIXEL_ADDRESS { pRow = PIXEL_ADDRESS( FixedToInt(fxLeftEdge), iy ); 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, fy). 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. */ #if INTERP_Z { GLfloat z0; z0 = VB->Win[vLower][2] + ctx->PolygonZoffset; /* interpolate depth values exactly */ fz = (GLint) (z0 + dzdx*FixedToFloat(adjx) + dzdy*FixedToFloat(adjy)); fdzOuter = (GLint) (dzdy + dxOuter * dzdx); zRow = Z_ADDRESS( ctx, FixedToInt(fxLeftEdge), iy ); dZRowOuter = (ctx->Buffer->Width + idxOuter) * sizeof(GLdepth); } #endif #if INTERP_RGB fr = (GLfixed)(IntToFixed(VB->Color[vLower][0]) + drdx * adjx + drdy * adjy) + FIXED_HALF; fdrOuter = SignedFloatToFixed(drdy + dxOuter * drdx); fg = (GLfixed)(IntToFixed(VB->Color[vLower][1]) + dgdx * adjx + dgdy * adjy) + FIXED_HALF; fdgOuter = SignedFloatToFixed(dgdy + dxOuter * dgdx); fb = (GLfixed)(IntToFixed(VB->Color[vLower][2]) + dbdx * adjx + dbdy * adjy) + FIXED_HALF; fdbOuter = SignedFloatToFixed(dbdy + dxOuter * dbdx); #endif #if INTERP_ALPHA fa = (GLfixed)(IntToFixed(VB->Color[vLower][3]) + dadx * adjx + dady * adjy) + FIXED_HALF; fdaOuter = SignedFloatToFixed(dady + dxOuter * dadx); #endif #if INTERP_INDEX fi = (GLfixed)(VB->Index[vLower] * FIXED_SCALE + didx * adjx + didy * adjy) + FIXED_HALF; fdiOuter = SignedFloatToFixed(didy + dxOuter * didx); #endif #if INTERP_ST { GLfloat s0, t0; s0 = VB->TexCoord[vLower][0] * S_SCALE; fs = (GLfixed)(s0 * FIXED_SCALE + dsdx * adjx + dsdy * adjy) + FIXED_HALF; fdsOuter = SignedFloatToFixed(dsdy + dxOuter * dsdx); t0 = VB->TexCoord[vLower][1] * T_SCALE; ft = (GLfixed)(t0 * FIXED_SCALE + dtdx * adjx + dtdy * adjy) + FIXED_HALF; fdtOuter = SignedFloatToFixed(dtdy + dxOuter * dtdx); } #endif #if INTERP_STW { GLfloat w0 = 1.0F / VB->Clip[vLower][3]; GLfloat s0, t0, u0, v0; wLeft = w0 + (dwdx * adjx + dwdy * adjy) * (1.0F/FIXED_SCALE); dwOuter = dwdy + dxOuter * dwdx; s0 = VB->TexCoord[vLower][0] * w0; sLeft = s0 + (dsdx * adjx + dsdy * adjy) * (1.0F/FIXED_SCALE); dsOuter = dsdy + dxOuter * dsdx; t0 = VB->TexCoord[vLower][1] * w0; tLeft = t0 + (dtdx * adjx + dtdy * adjy) * (1.0F/FIXED_SCALE); dtOuter = dtdy + dxOuter * dtdx; #if INTERP_UV u0 = VB->TexCoord[vLower][2] * w0; uLeft = u0 + (dudx * adjx + dudy * adjy) * (1.0F/FIXED_SCALE); duOuter = dudy + dxOuter * dudx; /* Note: don't divide V component by W */ v0 = VB->TexCoord[vLower][3]; vLeft = v0 + (dvdx * adjx + dvdy * adjy) * (1.0F/FIXED_SCALE); dvOuter = dvdy + dxOuter * dvdx; #endif } #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 #if INTERP_Z dZRowInner = dZRowOuter + sizeof(GLdepth); fdzInner = fdzOuter + fdzdx; #endif #if INTERP_RGB fdrInner = fdrOuter + fdrdx; fdgInner = fdgOuter + fdgdx; fdbInner = fdbOuter + fdbdx; #endif #if INTERP_ALPHA fdaInner = fdaOuter + fdadx; #endif #if INTERP_INDEX fdiInner = fdiOuter + fdidx; #endif #if INTERP_ST fdsInner = fdsOuter + fdsdx; fdtInner = fdtOuter + fdtdx; #endif #if INTERP_STW dwInner = dwOuter + dwdx; dsInner = dsOuter + dsdx; dtInner = dtOuter + dtdx; #if INTERP_UV duInner = duOuter + dudx; dvInner = dvOuter + dvdx; #endif #endif while (lines>0) { /* initialize the span interpolants to the leftmost value */ /* ff = fixed-pt fragment */ #if INTERP_Z GLfixed ffz = fz; /*GLdepth *zp = zRow;*/ #endif #if INTERP_RGB GLfixed ffr = fr, ffg = fg, ffb = fb; #endif #if INTERP_ALPHA GLfixed ffa = fa; #endif #if INTERP_INDEX GLfixed ffi = fi; #endif #if INTERP_ST GLfixed ffs = fs, fft = ft; #endif #if INTERP_STW GLfloat ss = sLeft, tt = tLeft, ww = wLeft; #endif #if INTERP_UV GLfloat uu = uLeft, vv = vLeft; #endif GLint left = FixedToInt(fxLeftEdge); GLint right = FixedToInt(fxRightEdge); #if INTERP_RGB { /* need this to accomodate round-off errors */ GLfixed ffrend = ffr+(right-left-1)*fdrdx; GLfixed ffgend = ffg+(right-left-1)*fdgdx; GLfixed ffbend = ffb+(right-left-1)*fdbdx; if (ffrend<0) ffr -= ffrend; if (ffgend<0) ffg -= ffgend; if (ffbend<0) ffb -= ffbend; if (ffr<0) ffr = 0; if (ffg<0) ffg = 0; if (ffb<0) ffb = 0; } #endif #if INTERP_ALPHA { GLfixed ffaend = ffa+(right-left-1)*fdadx; if (ffaend<0) ffa -= ffaend; if (ffa<0) ffa = 0; } #endif #if INTERP_INDEX if (ffi<0) ffi = 0; #endif INNER_LOOP( left, right, iy ); /* * 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. */ iy++; lines--; fxLeftEdge += fdxLeftEdge; fxRightEdge += fdxRightEdge; fError += fdError; if (fError >= 0) { fError -= FIXED_ONE; #ifdef PIXEL_ADDRESS pRow = (PIXEL_TYPE*) ((GLubyte*)pRow + dPRowOuter); #endif #if INTERP_Z zRow = (GLdepth*) ((GLubyte*)zRow + dZRowOuter); fz += fdzOuter; #endif #if INTERP_RGB fr += fdrOuter; fg += fdgOuter; fb += fdbOuter; #endif #if INTERP_ALPHA fa += fdaOuter; #endif #if INTERP_INDEX fi += fdiOuter; #endif #if INTERP_ST fs += fdsOuter; ft += fdtOuter; #endif #if INTERP_STW sLeft += dsOuter; tLeft += dtOuter; wLeft += dwOuter; #endif #if INTERP_UV uLeft += duOuter; vLeft += dvOuter; #endif } else { #ifdef PIXEL_ADDRESS pRow = (PIXEL_TYPE*) ((GLubyte*)pRow + dPRowInner); #endif #if INTERP_Z zRow = (GLdepth*) ((GLubyte*)zRow + dZRowInner); fz += fdzInner; #endif #if INTERP_RGB fr += fdrInner; fg += fdgInner; fb += fdbInner; #endif #if INTERP_ALPHA fa += fdaInner; #endif #if INTERP_INDEX fi += fdiInner; #endif #if INTERP_ST fs += fdsInner; ft += fdtInner; #endif #if INTERP_STW sLeft += dsInner; tLeft += dtInner; wLeft += dwInner; #endif #if INTERP_UV uLeft += duInner; vLeft += dvInner; #endif } } /*while lines>0*/ } /* for subTriangle */ } } } #undef SETUP_CODE #undef INNER_LOOP #undef PIXEL_TYPE #undef BYTES_PER_ROW #undef PIXEL_ADDRESS #undef INTERP_Z #undef INTERP_RGB #undef INTERP_ALPHA #undef INTERP_INDEX #undef INTERP_ST #undef INTERP_STW #undef INTERP_UV #undef S_SCALE #undef T_SCALE