/* $Id: linetemp.h,v 1.3 1999/11/24 18:48:31 brianp Exp $ */ /* * Mesa 3-D graphics library * Version: 3.1 * * Copyright (C) 1999 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 * BRIAN PAUL 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. */ /* * Line Rasterizer Template * * This file is #include'd to generate custom line rasterizers. * * The following macros may be defined to indicate what auxillary information * must be interplated along the line: * INTERP_Z - if defined, interpolate Z values * INTERP_RGB - if defined, interpolate RGB values * INTERP_SPEC - if defined, interpolate specular 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_STUV0 - if defined, interpolate unit 0 STU texcoords with * perspective correction * NOTE: OpenGL STRQ = Mesa STUV (R was taken for red) * INTERP_STUV1 - if defined, interpolate unit 1 STU texcoords * * When one can directly address pixels in the color buffer the following * macros can be defined and used to directly compute pixel addresses during * rasterization (see pixelPtr): * 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 * SETUP_CODE - code which is to be executed once per line * * To enable line stippling define STIPPLE = 1 * To enable wide lines define WIDE = 1 * * To actually "plot" each pixel either the PLOT macro or * (XMAJOR_PLOT and YMAJOR_PLOT macros) must be defined... * PLOT(X,Y) - code to plot a pixel. Example: * if (Z < *zPtr) { * *zPtr = Z; * color = pack_rgb( FixedToInt(r0), FixedToInt(g0), * FixedToInt(b0) ); * put_pixel( X, Y, color ); * } * * This code was designed for the origin to be in the lower-left corner. * */ /*void line( GLcontext *ctx, GLuint vert0, GLuint vert1, GLuint pvert )*/ { const struct vertex_buffer *VB = ctx->VB; GLint x0 = (GLint) VB->Win.data[vert0][0]; GLint x1 = (GLint) VB->Win.data[vert1][0]; GLint y0 = (GLint) VB->Win.data[vert0][1]; GLint y1 = (GLint) VB->Win.data[vert1][1]; GLint dx, dy; #if INTERP_XY GLint xstep, ystep; #endif #if INTERP_Z GLint z0, z1, dz, zPtrXstep, zPtrYstep; GLdepth *zPtr; #endif #if INTERP_RGB GLfixed r0 = IntToFixed(VB->ColorPtr->data[vert0][0]); GLfixed dr = IntToFixed(VB->ColorPtr->data[vert1][0]) - r0; GLfixed g0 = IntToFixed(VB->ColorPtr->data[vert0][1]); GLfixed dg = IntToFixed(VB->ColorPtr->data[vert1][1]) - g0; GLfixed b0 = IntToFixed(VB->ColorPtr->data[vert0][2]); GLfixed db = IntToFixed(VB->ColorPtr->data[vert1][2]) - b0; #endif #if INTERP_SPEC GLfixed sr0 = VB->Specular ? IntToFixed(VB->Specular[vert0][0]) : 0; GLfixed dsr = VB->Specular ? IntToFixed(VB->Specular[vert1][0]) - sr0 : 0; GLfixed sg0 = VB->Specular ? IntToFixed(VB->Specular[vert0][1]) : 0; GLfixed dsg = VB->Specular ? IntToFixed(VB->Specular[vert1][1]) - sg0 : 0; GLfixed sb0 = VB->Specular ? IntToFixed(VB->Specular[vert0][2]) : 0; GLfixed dsb = VB->Specular ? IntToFixed(VB->Specular[vert1][2]) - sb0 : 0; #endif #if INTERP_ALPHA GLfixed a0 = IntToFixed(VB->ColorPtr->data[vert0][3]); GLfixed da = IntToFixed(VB->ColorPtr->data[vert1][3]) - a0; #endif #if INTERP_INDEX GLint i0 = VB->IndexPtr->data[vert0] << 8; GLint di = (GLint) (VB->IndexPtr->data[vert1] << 8)-i0; #endif #if INTERP_ST GLfixed s0 = FloatToFixed(VB->TexCoord[vert0][0] * S_SCALE); GLfixed ds = FloatToFixed(VB->TexCoord[vert1][0] * S_SCALE) - s0; GLfixed t0 = FloatToFixed(VB->TexCoord[vert0][1] * T_SCALE); GLfixed dt = FloatToFixed(VB->TexCoord[vert1][1] * T_SCALE) - t0; #endif #if INTERP_STUV0 || INTERP_STUV1 GLfloat invw0 = VB->Win.data[vert0][3]; GLfloat invw1 = VB->Win.data[vert1][3]; #endif #if INTERP_STUV0 /* h denotes hyperbolic */ GLfloat hs0 = invw0 * VB->TexCoordPtr[0]->data[vert0][0]; GLfloat dhs = invw1 * VB->TexCoordPtr[0]->data[vert1][0] - hs0; GLfloat ht0 = invw0 * VB->TexCoordPtr[0]->data[vert0][1]; GLfloat dht = invw1 * VB->TexCoordPtr[0]->data[vert1][1] - ht0; GLfloat hu0 = 0, dhu = 0; GLfloat hv0 = invw0, dhv = invw1 - invw0; #endif #if INTERP_STUV1 GLfloat hs01 = invw0 * VB->TexCoordPtr[1]->data[vert0][0]; GLfloat dhs1 = invw1 * VB->TexCoordPtr[1]->data[vert1][0] - hs01; GLfloat ht01 = invw0 * VB->TexCoordPtr[1]->data[vert0][1]; GLfloat dht1 = invw1 * VB->TexCoordPtr[1]->data[vert1][1] - ht01; GLfloat hu01 = 0, dhu1 = 0; GLfloat hv01 = invw0, dhv1 = invw1 - invw0; #endif #ifdef PIXEL_ADDRESS PIXEL_TYPE *pixelPtr; GLint pixelXstep, pixelYstep; #endif #if WIDE /* for wide lines, draw all X in [x+min, x+max] or Y in [y+min, y+max] */ GLint width, min, max; width = (GLint) CLAMP( ctx->Line.Width, MIN_LINE_WIDTH, MAX_LINE_WIDTH ); min = (width-1) / -2; max = min + width - 1; #endif #if INTERP_STUV0 if (VB->TexCoordPtr[0]->size > 2) { hu0 = invw0 * VB->TexCoordPtr[0]->data[vert0][2]; dhu = invw1 * VB->TexCoordPtr[0]->data[vert1][2] - hu0; if (VB->TexCoordPtr[0]->size > 3) { hv0 = invw0 * VB->TexCoordPtr[0]->data[vert0][3]; dhv = invw1 * VB->TexCoordPtr[0]->data[vert1][3] - hv0; } } #endif #if INTERP_STUV1 if (VB->TexCoordPtr[1]->size > 2) { hu01 = invw0 * VB->TexCoordPtr[1]->data[vert0][2]; dhu1 = invw1 * VB->TexCoordPtr[1]->data[vert1][2] - hu01; if (VB->TexCoordPtr[1]->size > 3) { hv01 = invw0 * VB->TexCoordPtr[1]->data[vert0][3]; dhv1 = invw1 * VB->TexCoordPtr[1]->data[vert1][3] - hv01; } } #endif /* * Despite being clipped to the view volume, the line's window coordinates * may just lie outside the window bounds. That is, if the legal window * coordinates are [0,W-1][0,H-1], it's possible for x==W and/or y==H. * This quick and dirty code nudges the endpoints inside the window if * necessary. */ #if CLIP_HACK { GLint w = ctx->DrawBuffer->Width; GLint h = ctx->DrawBuffer->Height; if ((x0==w) | (x1==w)) { if ((x0==w) & (x1==w)) return; x0 -= x0==w; x1 -= x1==w; } if ((y0==h) | (y1==h)) { if ((y0==h) & (y1==h)) return; y0 -= y0==h; y1 -= y1==h; } } #endif dx = x1 - x0; dy = y1 - y0; if (dx==0 && dy==0) { return; } /* * Setup */ #ifdef SETUP_CODE SETUP_CODE #endif #if INTERP_Z zPtr = Z_ADDRESS(ctx,x0,y0); # if DEPTH_BITS==16 z0 = FloatToFixed(VB->Win.data[vert0][2]); z1 = FloatToFixed(VB->Win.data[vert1][2]); # else z0 = (int) VB->Win.data[vert0][2]; z1 = (int) VB->Win.data[vert1][2]; # endif #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE *) PIXEL_ADDRESS(x0,y0); #endif if (dx<0) { dx = -dx; /* make positive */ #if INTERP_XY xstep = -1; #endif #ifdef INTERP_Z zPtrXstep = -((GLint)sizeof(GLdepth)); #endif #ifdef PIXEL_ADDRESS pixelXstep = -((GLint)sizeof(PIXEL_TYPE)); #endif } else { #if INTERP_XY xstep = 1; #endif #if INTERP_Z zPtrXstep = ((GLint)sizeof(GLdepth)); #endif #ifdef PIXEL_ADDRESS pixelXstep = ((GLint)sizeof(PIXEL_TYPE)); #endif } if (dy<0) { dy = -dy; /* make positive */ #if INTERP_XY ystep = -1; #endif #if INTERP_Z zPtrYstep = -ctx->DrawBuffer->Width * ((GLint)sizeof(GLdepth)); #endif #ifdef PIXEL_ADDRESS pixelYstep = BYTES_PER_ROW; #endif } else { #if INTERP_XY ystep = 1; #endif #if INTERP_Z zPtrYstep = ctx->DrawBuffer->Width * ((GLint)sizeof(GLdepth)); #endif #ifdef PIXEL_ADDRESS pixelYstep = -(BYTES_PER_ROW); #endif } /* * Draw */ if (dx>dy) { /*** X-major line ***/ GLint i; GLint errorInc = dy+dy; GLint error = errorInc-dx; GLint errorDec = error-dx; #if INTERP_Z dz = (z1-z0) / dx; #endif #if INTERP_RGB dr /= dx; /* convert from whole line delta to per-pixel delta */ dg /= dx; db /= dx; #endif #if INTERP_SPEC dsr /= dx; /* convert from whole line delta to per-pixel delta */ dsg /= dx; dsb /= dx; #endif #if INTERP_ALPHA da /= dx; #endif #if INTERP_INDEX di /= dx; #endif #if INTERP_ST ds /= dx; dt /= dx; #endif #if INTERP_STUV0 { GLfloat invDx = 1.0F / (GLfloat) dx; dhs *= invDx; dht *= invDx; dhu *= invDx; dhv *= invDx; } #endif #if INTERP_STUV1 { GLfloat invDx = 1.0F / (GLfloat) dx; dhs1 *= invDx; dht1 *= invDx; dhu1 *= invDx; dhv1 *= invDx; } #endif for (i=0;iStippleCounter/ctx->Line.StippleFactor) & 0xf); if (ctx->Line.StipplePattern & m) { #endif #if INTERP_Z # if DEPTH_BITS==16 GLdepth Z = FixedToInt(z0); # else GLdepth Z = z0; # endif #endif #if INTERP_INDEX GLint I = i0 >> 8; #endif #if INTERP_STUV0 GLfloat invQ = 1.0F / hv0; GLfloat s = hs0 * invQ; GLfloat t = ht0 * invQ; GLfloat u = hu0 * invQ; #endif #if INTERP_STUV1 GLfloat invQ1 = 1.0F / hv01; GLfloat s1 = hs01 * invQ1; GLfloat t1 = ht01 * invQ1; GLfloat u1 = hu01 * invQ1; #endif #if WIDE GLint yy; GLint ymin = y0 + min; GLint ymax = y0 + max; for (yy=ymin;yy<=ymax;yy++) { PLOT( x0, yy ); } #else # ifdef XMAJOR_PLOT XMAJOR_PLOT( x0, y0 ); # else PLOT( x0, y0 ); # endif #endif /*WIDE*/ #if STIPPLE } ctx->StippleCounter++; #endif #if INTERP_XY x0 += xstep; #endif #if INTERP_Z zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrXstep); z0 += dz; #endif #if INTERP_RGB r0 += dr; g0 += dg; b0 += db; #endif #if INTERP_SPEC sr0 += dsr; sg0 += dsg; sb0 += dsb; #endif #if INTERP_ALPHA a0 += da; #endif #if INTERP_INDEX i0 += di; #endif #if INTERP_ST s0 += ds; t0 += dt; #endif #if INTERP_STUV0 hs0 += dhs; ht0 += dht; hu0 += dhu; hv0 += dhv; #endif #if INTERP_STUV1 hs01 += dhs1; ht01 += dht1; hu01 += dhu1; hv01 += dhv1; #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep); #endif if (error<0) { error += errorInc; } else { error += errorDec; #if INTERP_XY y0 += ystep; #endif #if INTERP_Z zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrYstep); #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep); #endif } } } else { /*** Y-major line ***/ GLint i; GLint errorInc = dx+dx; GLint error = errorInc-dy; GLint errorDec = error-dy; #if INTERP_Z dz = (z1-z0) / dy; #endif #if INTERP_RGB dr /= dy; /* convert from whole line delta to per-pixel delta */ dg /= dy; db /= dy; #endif #if INTERP_SPEC dsr /= dy; /* convert from whole line delta to per-pixel delta */ dsg /= dy; dsb /= dy; #endif #if INTERP_ALPHA da /= dy; #endif #if INTERP_INDEX di /= dy; #endif #if INTERP_ST ds /= dy; dt /= dy; #endif #if INTERP_STUV0 { GLfloat invDy = 1.0F / (GLfloat) dy; dhs *= invDy; dht *= invDy; dhu *= invDy; dhv *= invDy; } #endif #if INTERP_STUV1 { GLfloat invDy = 1.0F / (GLfloat) dy; dhs1 *= invDy; dht1 *= invDy; dhu1 *= invDy; dhv1 *= invDy; } #endif for (i=0;iStippleCounter/ctx->Line.StippleFactor) & 0xf); if (ctx->Line.StipplePattern & m) { #endif #if INTERP_Z # if DEPTH_BITS==16 GLdepth Z = FixedToInt(z0); # else GLdepth Z = z0; # endif #endif #if INTERP_INDEX GLint I = i0 >> 8; #endif #if INTERP_STUV0 GLfloat invQ = 1.0F / hv0; GLfloat s = hs0 * invQ; GLfloat t = ht0 * invQ; GLfloat u = hu0 * invQ; #endif #if INTERP_STUV1 GLfloat invQ1 = 1.0F / hv01; GLfloat s1 = hs01 * invQ1; GLfloat t1 = ht01 * invQ1; GLfloat u1 = hu01 * invQ1; #endif #if WIDE GLint xx; GLint xmin = x0 + min; GLint xmax = x0 + max; for (xx=xmin;xx<=xmax;xx++) { PLOT( xx, y0 ); } #else # ifdef YMAJOR_PLOT YMAJOR_PLOT( x0, y0 ); # else PLOT( x0, y0 ); # endif #endif /*WIDE*/ #if STIPPLE } ctx->StippleCounter++; #endif #if INTERP_XY y0 += ystep; #endif #if INTERP_Z zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrYstep); z0 += dz; #endif #if INTERP_RGB r0 += dr; g0 += dg; b0 += db; #endif #if INTERP_SPEC sr0 += dsr; sg0 += dsg; sb0 += dsb; #endif #if INTERP_ALPHA a0 += da; #endif #if INTERP_INDEX i0 += di; #endif #if INTERP_ST s0 += ds; t0 += dt; #endif #if INTERP_STUV0 hs0 += dhs; ht0 += dht; hu0 += dhu; hv0 += dhv; #endif #if INTERP_STUV1 hs01 += dhs1; ht01 += dht1; hu01 += dhu1; hv01 += dhv1; #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep); #endif if (error<0) { error += errorInc; } else { error += errorDec; #if INTERP_XY x0 += xstep; #endif #if INTERP_Z zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrXstep); #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep); #endif } } } } #undef INTERP_XY #undef INTERP_Z #undef INTERP_RGB #undef INTERP_SPEC #undef INTERP_ALPHA #undef INTERP_STUV0 #undef INTERP_STUV1 #undef INTERP_INDEX #undef PIXEL_ADDRESS #undef PIXEL_TYPE #undef BYTES_PER_ROW #undef SETUP_CODE #undef PLOT #undef XMAJOR_PLOT #undef YMAJOR_PLOT #undef CLIP_HACK #undef STIPPLE #undef WIDE