From 02afd45d3b2eccff5d566cdeb32b3211803bd500 Mon Sep 17 00:00:00 2001 From: Brian Date: Tue, 4 Dec 2007 14:06:10 -0700 Subject: [PATCH] fix span->facing computation and gl_FrontFacing initialization --- src/mesa/swrast/s_fragprog.c | 2 +- src/mesa/swrast/s_tritemp.h | 9 ++++----- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/src/mesa/swrast/s_fragprog.c b/src/mesa/swrast/s_fragprog.c index 767e485ede2..76c79eb0d81 100644 --- a/src/mesa/swrast/s_fragprog.c +++ b/src/mesa/swrast/s_fragprog.c @@ -120,7 +120,7 @@ init_machine(GLcontext *ctx, struct gl_program_machine *machine, /* if running a GLSL program (not ARB_fragment_program) */ if (ctx->Shader.CurrentProgram) { /* Store front/back facing value in register FOGC.Y */ - machine->Attribs[FRAG_ATTRIB_FOGC][col][1] = (GLfloat) span->facing; + machine->Attribs[FRAG_ATTRIB_FOGC][col][1] = 1.0 - span->facing; } machine->CurElement = col; diff --git a/src/mesa/swrast/s_tritemp.h b/src/mesa/swrast/s_tritemp.h index c609210c0ec..8e3c5b5eebb 100644 --- a/src/mesa/swrast/s_tritemp.h +++ b/src/mesa/swrast/s_tritemp.h @@ -136,7 +136,7 @@ static void NAME(GLcontext *ctx, const SWvertex *v0, EdgeT eMaj, eTop, eBot; GLfloat oneOverArea; const SWvertex *vMin, *vMid, *vMax; /* Y(vMin)<=Y(vMid)<=Y(vMax) */ - GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceCullSign; + GLfloat bf = SWRAST_CONTEXT(ctx)->_BackfaceSign; const GLint snapMask = ~((FIXED_ONE / (1 << SUB_PIXEL_BITS)) - 1); /* for x/y coord snapping */ GLfixed vMin_fx, vMin_fy, vMid_fx, vMid_fy, vMax_fx, vMax_fy; @@ -234,18 +234,17 @@ static void NAME(GLcontext *ctx, const SWvertex *v0, /* compute area, oneOverArea and perform backface culling */ { const GLfloat area = eMaj.dx * eBot.dy - eBot.dx * eMaj.dy; - /* Do backface culling */ - if (area * bf < 0.0) + if (IS_INF_OR_NAN(area) || area == 0.0F) return; - if (IS_INF_OR_NAN(area) || area == 0.0F) + if (area * bf * swrast->_BackfaceCullSign < 0.0) return; oneOverArea = 1.0F / area; /* 0 = front, 1 = back */ - span.facing = oneOverArea * swrast->_BackfaceSign > 0.0F; + span.facing = oneOverArea * bf > 0.0F; } /* Edge setup. For a triangle strip these could be reused... */ -- 2.30.2