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342 lines
12 KiB
C
342 lines
12 KiB
C
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/*
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* Mesa 3-D graphics library
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* Version: 7.0.3
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*
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* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* Antialiased Triangle Rasterizer Template
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*
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* This file is #include'd to generate custom AA triangle rasterizers.
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* NOTE: this code hasn't been optimized yet. That'll come after it
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* works correctly.
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*
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* The following macros may be defined to indicate what auxillary information
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* must be copmuted across the triangle:
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* DO_Z - if defined, compute Z values
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* DO_ATTRIBS - if defined, compute texcoords, varying, etc.
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*/
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/*void triangle( struct gl_context *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint pv )*/
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{
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const SWcontext *swrast = SWRAST_CONTEXT(ctx);
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const GLfloat *p0 = v0->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *p1 = v1->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *p2 = v2->attrib[FRAG_ATTRIB_WPOS];
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const SWvertex *vMin, *vMid, *vMax;
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GLint iyMin, iyMax;
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GLfloat yMin, yMax;
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GLboolean ltor;
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GLfloat majDx, majDy; /* major (i.e. long) edge dx and dy */
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SWspan span;
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#ifdef DO_Z
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GLfloat zPlane[4];
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#endif
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GLfloat rPlane[4], gPlane[4], bPlane[4], aPlane[4];
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#if defined(DO_ATTRIBS)
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GLfloat attrPlane[FRAG_ATTRIB_MAX][4][4];
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GLfloat wPlane[4]; /* win[3] */
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#endif
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GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceCullSign;
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(void) swrast;
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INIT_SPAN(span, GL_POLYGON);
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span.arrayMask = SPAN_COVERAGE;
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/* determine bottom to top order of vertices */
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{
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GLfloat y0 = v0->attrib[FRAG_ATTRIB_WPOS][1];
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GLfloat y1 = v1->attrib[FRAG_ATTRIB_WPOS][1];
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GLfloat y2 = v2->attrib[FRAG_ATTRIB_WPOS][1];
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if (y0 <= y1) {
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if (y1 <= y2) {
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vMin = v0; vMid = v1; vMax = v2; /* y0<=y1<=y2 */
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}
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else if (y2 <= y0) {
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vMin = v2; vMid = v0; vMax = v1; /* y2<=y0<=y1 */
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}
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else {
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vMin = v0; vMid = v2; vMax = v1; bf = -bf; /* y0<=y2<=y1 */
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}
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}
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else {
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if (y0 <= y2) {
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vMin = v1; vMid = v0; vMax = v2; bf = -bf; /* y1<=y0<=y2 */
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}
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else if (y2 <= y1) {
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vMin = v2; vMid = v1; vMax = v0; bf = -bf; /* y2<=y1<=y0 */
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}
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else {
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vMin = v1; vMid = v2; vMax = v0; /* y1<=y2<=y0 */
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}
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}
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}
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majDx = vMax->attrib[FRAG_ATTRIB_WPOS][0] - vMin->attrib[FRAG_ATTRIB_WPOS][0];
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majDy = vMax->attrib[FRAG_ATTRIB_WPOS][1] - vMin->attrib[FRAG_ATTRIB_WPOS][1];
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/* front/back-face determination and cullling */
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{
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const GLfloat botDx = vMid->attrib[FRAG_ATTRIB_WPOS][0] - vMin->attrib[FRAG_ATTRIB_WPOS][0];
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const GLfloat botDy = vMid->attrib[FRAG_ATTRIB_WPOS][1] - vMin->attrib[FRAG_ATTRIB_WPOS][1];
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const GLfloat area = majDx * botDy - botDx * majDy;
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/* Do backface culling */
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if (area * bf < 0 || area == 0 || IS_INF_OR_NAN(area))
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return;
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ltor = (GLboolean) (area < 0.0F);
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}
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/* Plane equation setup:
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* We evaluate plane equations at window (x,y) coordinates in order
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* to compute color, Z, fog, texcoords, etc. This isn't terribly
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* efficient but it's easy and reliable.
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*/
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#ifdef DO_Z
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compute_plane(p0, p1, p2, p0[2], p1[2], p2[2], zPlane);
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span.arrayMask |= SPAN_Z;
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#endif
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if (ctx->Light.ShadeModel == GL_SMOOTH) {
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compute_plane(p0, p1, p2, v0->color[RCOMP], v1->color[RCOMP], v2->color[RCOMP], rPlane);
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compute_plane(p0, p1, p2, v0->color[GCOMP], v1->color[GCOMP], v2->color[GCOMP], gPlane);
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compute_plane(p0, p1, p2, v0->color[BCOMP], v1->color[BCOMP], v2->color[BCOMP], bPlane);
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compute_plane(p0, p1, p2, v0->color[ACOMP], v1->color[ACOMP], v2->color[ACOMP], aPlane);
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}
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else {
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constant_plane(v2->color[RCOMP], rPlane);
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constant_plane(v2->color[GCOMP], gPlane);
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constant_plane(v2->color[BCOMP], bPlane);
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constant_plane(v2->color[ACOMP], aPlane);
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}
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span.arrayMask |= SPAN_RGBA;
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#if defined(DO_ATTRIBS)
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{
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const GLfloat invW0 = v0->attrib[FRAG_ATTRIB_WPOS][3];
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const GLfloat invW1 = v1->attrib[FRAG_ATTRIB_WPOS][3];
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const GLfloat invW2 = v2->attrib[FRAG_ATTRIB_WPOS][3];
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compute_plane(p0, p1, p2, invW0, invW1, invW2, wPlane);
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span.attrStepX[FRAG_ATTRIB_WPOS][3] = plane_dx(wPlane);
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span.attrStepY[FRAG_ATTRIB_WPOS][3] = plane_dy(wPlane);
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ATTRIB_LOOP_BEGIN
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GLuint c;
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if (swrast->_InterpMode[attr] == GL_FLAT) {
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for (c = 0; c < 4; c++) {
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constant_plane(v2->attrib[attr][c] * invW2, attrPlane[attr][c]);
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}
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}
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else {
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for (c = 0; c < 4; c++) {
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const GLfloat a0 = v0->attrib[attr][c] * invW0;
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const GLfloat a1 = v1->attrib[attr][c] * invW1;
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const GLfloat a2 = v2->attrib[attr][c] * invW2;
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compute_plane(p0, p1, p2, a0, a1, a2, attrPlane[attr][c]);
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}
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}
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for (c = 0; c < 4; c++) {
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span.attrStepX[attr][c] = plane_dx(attrPlane[attr][c]);
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span.attrStepY[attr][c] = plane_dy(attrPlane[attr][c]);
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}
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ATTRIB_LOOP_END
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}
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#endif
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/* Begin bottom-to-top scan over the triangle.
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* The long edge will either be on the left or right side of the
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* triangle. We always scan from the long edge toward the shorter
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* edges, stopping when we find that coverage = 0. If the long edge
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* is on the left we scan left-to-right. Else, we scan right-to-left.
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*/
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yMin = vMin->attrib[FRAG_ATTRIB_WPOS][1];
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yMax = vMax->attrib[FRAG_ATTRIB_WPOS][1];
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iyMin = (GLint) yMin;
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iyMax = (GLint) yMax + 1;
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if (ltor) {
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/* scan left to right */
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const GLfloat *pMin = vMin->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *pMid = vMid->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *pMax = vMax->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat dxdy = majDx / majDy;
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const GLfloat xAdj = dxdy < 0.0F ? -dxdy : 0.0F;
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GLint iy;
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#ifdef _OPENMP
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#pragma omp parallel for schedule(dynamic) private(iy) firstprivate(span)
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#endif
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for (iy = iyMin; iy < iyMax; iy++) {
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GLfloat x = pMin[0] - (yMin - iy) * dxdy;
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GLint ix, startX = (GLint) (x - xAdj);
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GLuint count;
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GLfloat coverage = 0.0F;
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#ifdef _OPENMP
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/* each thread needs to use a different (global) SpanArrays variable */
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span.array = SWRAST_CONTEXT(ctx)->SpanArrays + omp_get_thread_num();
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#endif
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/* skip over fragments with zero coverage */
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while (startX < MAX_WIDTH) {
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coverage = compute_coveragef(pMin, pMid, pMax, startX, iy);
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if (coverage > 0.0F)
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break;
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startX++;
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}
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/* enter interior of triangle */
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ix = startX;
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#if defined(DO_ATTRIBS)
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/* compute attributes at left-most fragment */
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span.attrStart[FRAG_ATTRIB_WPOS][3] = solve_plane(ix + 0.5F, iy + 0.5F, wPlane);
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ATTRIB_LOOP_BEGIN
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GLuint c;
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for (c = 0; c < 4; c++) {
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span.attrStart[attr][c] = solve_plane(ix + 0.5F, iy + 0.5F, attrPlane[attr][c]);
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}
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ATTRIB_LOOP_END
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#endif
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count = 0;
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while (coverage > 0.0F) {
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/* (cx,cy) = center of fragment */
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const GLfloat cx = ix + 0.5F, cy = iy + 0.5F;
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SWspanarrays *array = span.array;
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array->coverage[count] = coverage;
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#ifdef DO_Z
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array->z[count] = (GLuint) solve_plane(cx, cy, zPlane);
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#endif
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array->rgba[count][RCOMP] = solve_plane_chan(cx, cy, rPlane);
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array->rgba[count][GCOMP] = solve_plane_chan(cx, cy, gPlane);
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array->rgba[count][BCOMP] = solve_plane_chan(cx, cy, bPlane);
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array->rgba[count][ACOMP] = solve_plane_chan(cx, cy, aPlane);
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ix++;
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count++;
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coverage = compute_coveragef(pMin, pMid, pMax, ix, iy);
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}
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if (ix > startX) {
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span.x = startX;
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span.y = iy;
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span.end = (GLuint) ix - (GLuint) startX;
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_swrast_write_rgba_span(ctx, &span);
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}
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}
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}
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else {
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/* scan right to left */
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const GLfloat *pMin = vMin->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *pMid = vMid->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat *pMax = vMax->attrib[FRAG_ATTRIB_WPOS];
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const GLfloat dxdy = majDx / majDy;
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const GLfloat xAdj = dxdy > 0 ? dxdy : 0.0F;
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GLint iy;
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#ifdef _OPENMP
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#pragma omp parallel for schedule(dynamic) private(iy) firstprivate(span)
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#endif
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for (iy = iyMin; iy < iyMax; iy++) {
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GLfloat x = pMin[0] - (yMin - iy) * dxdy;
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GLint ix, left, startX = (GLint) (x + xAdj);
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GLuint count, n;
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GLfloat coverage = 0.0F;
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#ifdef _OPENMP
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/* each thread needs to use a different (global) SpanArrays variable */
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span.array = SWRAST_CONTEXT(ctx)->SpanArrays + omp_get_thread_num();
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#endif
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/* make sure we're not past the window edge */
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if (startX >= ctx->DrawBuffer->_Xmax) {
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startX = ctx->DrawBuffer->_Xmax - 1;
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}
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/* skip fragments with zero coverage */
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while (startX > 0) {
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coverage = compute_coveragef(pMin, pMax, pMid, startX, iy);
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if (coverage > 0.0F)
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break;
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startX--;
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}
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/* enter interior of triangle */
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ix = startX;
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count = 0;
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while (coverage > 0.0F) {
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/* (cx,cy) = center of fragment */
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const GLfloat cx = ix + 0.5F, cy = iy + 0.5F;
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SWspanarrays *array = span.array;
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ASSERT(ix >= 0);
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array->coverage[ix] = coverage;
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#ifdef DO_Z
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array->z[ix] = (GLuint) solve_plane(cx, cy, zPlane);
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#endif
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array->rgba[ix][RCOMP] = solve_plane_chan(cx, cy, rPlane);
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array->rgba[ix][GCOMP] = solve_plane_chan(cx, cy, gPlane);
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array->rgba[ix][BCOMP] = solve_plane_chan(cx, cy, bPlane);
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array->rgba[ix][ACOMP] = solve_plane_chan(cx, cy, aPlane);
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ix--;
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count++;
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coverage = compute_coveragef(pMin, pMax, pMid, ix, iy);
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}
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#if defined(DO_ATTRIBS)
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/* compute attributes at left-most fragment */
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span.attrStart[FRAG_ATTRIB_WPOS][3] = solve_plane(ix + 1.5F, iy + 0.5F, wPlane);
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ATTRIB_LOOP_BEGIN
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GLuint c;
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for (c = 0; c < 4; c++) {
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span.attrStart[attr][c] = solve_plane(ix + 1.5F, iy + 0.5F, attrPlane[attr][c]);
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}
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ATTRIB_LOOP_END
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#endif
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if (startX > ix) {
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n = (GLuint) startX - (GLuint) ix;
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left = ix + 1;
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/* shift all values to the left */
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/* XXX this is temporary */
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{
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SWspanarrays *array = span.array;
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GLint j;
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for (j = 0; j < (GLint) n; j++) {
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array->coverage[j] = array->coverage[j + left];
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COPY_CHAN4(array->rgba[j], array->rgba[j + left]);
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#ifdef DO_Z
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array->z[j] = array->z[j + left];
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#endif
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}
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}
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span.x = left;
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span.y = iy;
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span.end = n;
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_swrast_write_rgba_span(ctx, &span);
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}
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}
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}
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}
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#undef DO_Z
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#undef DO_ATTRIBS
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#undef DO_OCCLUSION_TEST
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