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* Mesa 3-D graphics library
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* Copyright (C) 1999-2004 Brian Paul All Rights Reserved.
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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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* 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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* 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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* Keith Whitwell <keith@tungstengraphics.com>
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static void TAG(triangle)(GLcontext *ctx, GLuint e0, GLuint e1, GLuint e2 )
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struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
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SWvertex *verts = SWSETUP_CONTEXT(ctx)->verts;
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GLenum mode = GL_FILL;
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GLchan saved_color[3][4];
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GLchan saved_spec[3][4];
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GLfloat saved_index[3];
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if (IND & (SS_TWOSIDE_BIT | SS_OFFSET_BIT | SS_UNFILLED_BIT))
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GLfloat ex = v[0]->win[0] - v[2]->win[0];
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GLfloat ey = v[0]->win[1] - v[2]->win[1];
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GLfloat fx = v[1]->win[0] - v[2]->win[0];
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GLfloat fy = v[1]->win[1] - v[2]->win[1];
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GLfloat cc = ex*fy - ey*fx;
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if (IND & (SS_TWOSIDE_BIT | SS_UNFILLED_BIT))
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facing = (cc < 0.0) ^ ctx->Polygon._FrontBit;
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if (IND & SS_UNFILLED_BIT)
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mode = facing ? ctx->Polygon.BackMode : ctx->Polygon.FrontMode;
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if (IND & SS_TWOSIDE_BIT) {
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if (IND & SS_RGBA_BIT) {
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if (VB->ColorPtr[1]) {
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GLfloat (*vbcolor)[4] = VB->ColorPtr[1]->data;
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COPY_CHAN4(saved_color[0], v[0]->color);
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COPY_CHAN4(saved_color[1], v[1]->color);
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COPY_CHAN4(saved_color[2], v[2]->color);
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if (VB->ColorPtr[1]->stride) {
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SS_COLOR(v[0]->color, vbcolor[e0]);
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SS_COLOR(v[1]->color, vbcolor[e1]);
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SS_COLOR(v[2]->color, vbcolor[e2]);
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SS_COLOR(v[0]->color, vbcolor[0]);
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SS_COLOR(v[1]->color, vbcolor[0]);
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SS_COLOR(v[2]->color, vbcolor[0]);
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if (VB->SecondaryColorPtr[1]) {
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GLfloat (*vbspec)[4] = VB->SecondaryColorPtr[1]->data;
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COPY_CHAN4(saved_spec[0], v[0]->specular);
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COPY_CHAN4(saved_spec[1], v[1]->specular);
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COPY_CHAN4(saved_spec[2], v[2]->specular);
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if (VB->SecondaryColorPtr[1]->stride) {
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SS_SPEC(v[0]->specular, vbspec[e0]);
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SS_SPEC(v[1]->specular, vbspec[e1]);
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SS_SPEC(v[2]->specular, vbspec[e2]);
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SS_SPEC(v[0]->specular, vbspec[0]);
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SS_SPEC(v[1]->specular, vbspec[0]);
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SS_SPEC(v[2]->specular, vbspec[0]);
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GLfloat *vbindex = (GLfloat *)VB->IndexPtr[1]->data;
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saved_index[0] = v[0]->index;
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saved_index[1] = v[1]->index;
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saved_index[2] = v[2]->index;
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SS_IND(v[0]->index, (GLuint) vbindex[e0]);
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SS_IND(v[1]->index, (GLuint) vbindex[e1]);
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SS_IND(v[2]->index, (GLuint) vbindex[e2]);
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if (IND & SS_OFFSET_BIT)
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offset = ctx->Polygon.OffsetUnits * ctx->DrawBuffer->_MRD;
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if (cc * cc > 1e-16) {
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const GLfloat ez = z[0] - z[2];
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const GLfloat fz = z[1] - z[2];
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const GLfloat oneOverArea = 1.0F / cc;
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const GLfloat dzdx = FABSF((ey * fz - ez * fy) * oneOverArea);
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const GLfloat dzdy = FABSF((ez * fx - ex * fz) * oneOverArea);
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offset += MAX2(dzdx, dzdy) * ctx->Polygon.OffsetFactor;
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/* Unfortunately, we need to clamp to prevent negative Zs below.
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* Technically, we should do the clamping per-fragment.
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offset = MAX2(offset, -v[0]->win[2]);
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offset = MAX2(offset, -v[1]->win[2]);
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offset = MAX2(offset, -v[2]->win[2]);
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if (mode == GL_POINT) {
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if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetPoint) {
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v[0]->win[2] += offset;
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v[1]->win[2] += offset;
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v[2]->win[2] += offset;
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_swsetup_render_point_tri( ctx, e0, e1, e2, facing );
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} else if (mode == GL_LINE) {
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if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetLine) {
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v[0]->win[2] += offset;
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v[1]->win[2] += offset;
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v[2]->win[2] += offset;
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_swsetup_render_line_tri( ctx, e0, e1, e2, facing );
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if ((IND & SS_OFFSET_BIT) && ctx->Polygon.OffsetFill) {
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v[0]->win[2] += offset;
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v[1]->win[2] += offset;
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v[2]->win[2] += offset;
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_swrast_Triangle( ctx, v[0], v[1], v[2] );
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if (IND & SS_OFFSET_BIT) {
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if (IND & SS_TWOSIDE_BIT) {
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if (IND & SS_RGBA_BIT) {
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if (VB->ColorPtr[1]) {
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COPY_CHAN4(v[0]->color, saved_color[0]);
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COPY_CHAN4(v[1]->color, saved_color[1]);
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COPY_CHAN4(v[2]->color, saved_color[2]);
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if (VB->SecondaryColorPtr[1]) {
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COPY_CHAN4(v[0]->specular, saved_spec[0]);
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COPY_CHAN4(v[1]->specular, saved_spec[1]);
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COPY_CHAN4(v[2]->specular, saved_spec[2]);
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v[0]->index = saved_index[0];
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v[1]->index = saved_index[1];
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v[2]->index = saved_index[2];
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/* Need to fixup edgeflags when decomposing to triangles:
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static void TAG(quadfunc)( GLcontext *ctx, GLuint v0,
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GLuint v1, GLuint v2, GLuint v3 )
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if (IND & SS_UNFILLED_BIT) {
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struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
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if (VB->EdgeFlag) { /* XXX this test shouldn't be needed (bug 12614) */
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GLubyte ef1 = VB->EdgeFlag[v1];
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GLubyte ef3 = VB->EdgeFlag[v3];
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VB->EdgeFlag[v1] = 0;
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TAG(triangle)( ctx, v0, v1, v3 );
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VB->EdgeFlag[v1] = ef1;
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VB->EdgeFlag[v3] = 0;
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TAG(triangle)( ctx, v1, v2, v3 );
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VB->EdgeFlag[v3] = ef3;
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TAG(triangle)( ctx, v0, v1, v3 );
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TAG(triangle)( ctx, v1, v2, v3 );
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static void TAG(init)( void )
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tri_tab[IND] = TAG(triangle);
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quad_tab[IND] = TAG(quadfunc);