/* * Mesa 3-D graphics library * * Copyright (C) 1999-2007 Brian Paul All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ /* * 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_ATTRIBS - if defined, interpolate attribs (texcoords, varying, etc) * * 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. * * Similarly, for direct depth buffer access, this type is used for depth * buffer addressing: * DEPTH_TYPE - either GLushort or GLuint * * Optionally, one may provide one-time setup code * SETUP_CODE - code which is to be executed once per line * * To actually "plot" each pixel the PLOT macro 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. * */ static void NAME( struct gl_context *ctx, const SWvertex *vert0, const SWvertex *vert1 ) { const SWcontext *swrast = SWRAST_CONTEXT(ctx); SWspan span; GLuint interpFlags = 0; GLint x0 = (GLint) vert0->attrib[VARYING_SLOT_POS][0]; GLint x1 = (GLint) vert1->attrib[VARYING_SLOT_POS][0]; GLint y0 = (GLint) vert0->attrib[VARYING_SLOT_POS][1]; GLint y1 = (GLint) vert1->attrib[VARYING_SLOT_POS][1]; GLint dx, dy; GLint numPixels; GLint xstep, ystep; #if defined(DEPTH_TYPE) const GLint depthBits = ctx->DrawBuffer->Visual.depthBits; const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0; struct gl_renderbuffer *zrb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer; #define FixedToDepth(F) ((F) >> fixedToDepthShift) GLint zPtrXstep, zPtrYstep; DEPTH_TYPE *zPtr; #elif defined(INTERP_Z) const GLint depthBits = ctx->DrawBuffer->Visual.depthBits; #endif #ifdef PIXEL_ADDRESS PIXEL_TYPE *pixelPtr; GLint pixelXstep, pixelYstep; #endif #ifdef SETUP_CODE SETUP_CODE #endif (void) swrast; /* Cull primitives with malformed coordinates. */ { GLfloat tmp = vert0->attrib[VARYING_SLOT_POS][0] + vert0->attrib[VARYING_SLOT_POS][1] + vert1->attrib[VARYING_SLOT_POS][0] + vert1->attrib[VARYING_SLOT_POS][1]; if (IS_INF_OR_NAN(tmp)) return; } /* printf("%s():\n", __FUNCTION__); printf(" (%f, %f, %f) -> (%f, %f, %f)\n", vert0->attrib[VARYING_SLOT_POS][0], vert0->attrib[VARYING_SLOT_POS][1], vert0->attrib[VARYING_SLOT_POS][2], vert1->attrib[VARYING_SLOT_POS][0], vert1->attrib[VARYING_SLOT_POS][1], vert1->attrib[VARYING_SLOT_POS][2]); printf(" (%d, %d, %d) -> (%d, %d, %d)\n", vert0->color[0], vert0->color[1], vert0->color[2], vert1->color[0], vert1->color[1], vert1->color[2]); printf(" (%d, %d, %d) -> (%d, %d, %d)\n", vert0->specular[0], vert0->specular[1], vert0->specular[2], vert1->specular[0], vert1->specular[1], vert1->specular[2]); */ /* * 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. */ #ifdef 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; /* printf("%s %d,%d %g %g %g %g %g %g %g %g\n", __FUNCTION__, dx, dy, vert0->attrib[VARYING_SLOT_COL1][0], vert0->attrib[VARYING_SLOT_COL1][1], vert0->attrib[VARYING_SLOT_COL1][2], vert0->attrib[VARYING_SLOT_COL1][3], vert1->attrib[VARYING_SLOT_COL1][0], vert1->attrib[VARYING_SLOT_COL1][1], vert1->attrib[VARYING_SLOT_COL1][2], vert1->attrib[VARYING_SLOT_COL1][3]); */ #ifdef DEPTH_TYPE zPtr = (DEPTH_TYPE *) _swrast_pixel_address(zrb, x0, y0); #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE *) PIXEL_ADDRESS(x0,y0); #endif if (dx<0) { dx = -dx; /* make positive */ xstep = -1; #ifdef DEPTH_TYPE zPtrXstep = -((GLint)sizeof(DEPTH_TYPE)); #endif #ifdef PIXEL_ADDRESS pixelXstep = -((GLint)sizeof(PIXEL_TYPE)); #endif } else { xstep = 1; #ifdef DEPTH_TYPE zPtrXstep = ((GLint)sizeof(DEPTH_TYPE)); #endif #ifdef PIXEL_ADDRESS pixelXstep = ((GLint)sizeof(PIXEL_TYPE)); #endif } if (dy<0) { dy = -dy; /* make positive */ ystep = -1; #ifdef DEPTH_TYPE zPtrYstep = -((GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE))); #endif #ifdef PIXEL_ADDRESS pixelYstep = BYTES_PER_ROW; #endif } else { ystep = 1; #ifdef DEPTH_TYPE zPtrYstep = (GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE)); #endif #ifdef PIXEL_ADDRESS pixelYstep = -(BYTES_PER_ROW); #endif } ASSERT(dx >= 0); ASSERT(dy >= 0); numPixels = MAX2(dx, dy); /* * Span setup: compute start and step values for all interpolated values. */ interpFlags |= SPAN_RGBA; if (ctx->Light.ShadeModel == GL_SMOOTH) { span.red = ChanToFixed(vert0->color[0]); span.green = ChanToFixed(vert0->color[1]); span.blue = ChanToFixed(vert0->color[2]); span.alpha = ChanToFixed(vert0->color[3]); span.redStep = (ChanToFixed(vert1->color[0]) - span.red ) / numPixels; span.greenStep = (ChanToFixed(vert1->color[1]) - span.green) / numPixels; span.blueStep = (ChanToFixed(vert1->color[2]) - span.blue ) / numPixels; span.alphaStep = (ChanToFixed(vert1->color[3]) - span.alpha) / numPixels; } else { span.red = ChanToFixed(vert1->color[0]); span.green = ChanToFixed(vert1->color[1]); span.blue = ChanToFixed(vert1->color[2]); span.alpha = ChanToFixed(vert1->color[3]); span.redStep = 0; span.greenStep = 0; span.blueStep = 0; span.alphaStep = 0; } #if defined(INTERP_Z) || defined(DEPTH_TYPE) interpFlags |= SPAN_Z; { if (depthBits <= 16) { span.z = FloatToFixed(vert0->attrib[VARYING_SLOT_POS][2]) + FIXED_HALF; span.zStep = FloatToFixed( vert1->attrib[VARYING_SLOT_POS][2] - vert0->attrib[VARYING_SLOT_POS][2]) / numPixels; } else { /* don't use fixed point */ span.z = (GLuint) vert0->attrib[VARYING_SLOT_POS][2]; span.zStep = (GLint) (( vert1->attrib[VARYING_SLOT_POS][2] - vert0->attrib[VARYING_SLOT_POS][2]) / numPixels); } } #endif #if defined(INTERP_ATTRIBS) { const GLfloat invLen = 1.0F / numPixels; const GLfloat invw0 = vert0->attrib[VARYING_SLOT_POS][3]; const GLfloat invw1 = vert1->attrib[VARYING_SLOT_POS][3]; span.attrStart[VARYING_SLOT_POS][3] = invw0; span.attrStepX[VARYING_SLOT_POS][3] = (invw1 - invw0) * invLen; span.attrStepY[VARYING_SLOT_POS][3] = 0.0; ATTRIB_LOOP_BEGIN if (swrast->_InterpMode[attr] == GL_FLAT) { COPY_4V(span.attrStart[attr], vert1->attrib[attr]); ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0); } else { GLuint c; for (c = 0; c < 4; c++) { float da; span.attrStart[attr][c] = invw0 * vert0->attrib[attr][c]; da = (invw1 * vert1->attrib[attr][c]) - span.attrStart[attr][c]; span.attrStepX[attr][c] = da * invLen; } } ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0); ATTRIB_LOOP_END } #endif INIT_SPAN(span, GL_LINE); span.end = numPixels; span.interpMask = interpFlags; span.arrayMask = SPAN_XY; span.facing = swrast->PointLineFacing; /* * Draw */ if (dx > dy) { /*** X-major line ***/ GLint i; GLint errorInc = dy+dy; GLint error = errorInc-dx; GLint errorDec = error-dx; for (i = 0; i < dx; i++) { #ifdef DEPTH_TYPE GLuint Z = FixedToDepth(span.z); #endif #ifdef PLOT PLOT( x0, y0 ); #else span.array->x[i] = x0; span.array->y[i] = y0; #endif x0 += xstep; #ifdef DEPTH_TYPE zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep); span.z += span.zStep; #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep); #endif if (error < 0) { error += errorInc; } else { error += errorDec; y0 += ystep; #ifdef DEPTH_TYPE zPtr = (DEPTH_TYPE *) ((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; for (i=0;i<dy;i++) { #ifdef DEPTH_TYPE GLuint Z = FixedToDepth(span.z); #endif #ifdef PLOT PLOT( x0, y0 ); #else span.array->x[i] = x0; span.array->y[i] = y0; #endif y0 += ystep; #ifdef DEPTH_TYPE zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrYstep); span.z += span.zStep; #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep); #endif if (error<0) { error += errorInc; } else { error += errorDec; x0 += xstep; #ifdef DEPTH_TYPE zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep); #endif #ifdef PIXEL_ADDRESS pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep); #endif } } } #ifdef RENDER_SPAN RENDER_SPAN( span ); #endif (void)span; } #undef NAME #undef INTERP_Z #undef INTERP_ATTRIBS #undef PIXEL_ADDRESS #undef PIXEL_TYPE #undef DEPTH_TYPE #undef BYTES_PER_ROW #undef SETUP_CODE #undef PLOT #undef CLIP_HACK #undef FixedToDepth #undef RENDER_SPAN