From 5bd2987840567047f19cc2dad6fc5f3fb84345fc Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Wed, 16 Feb 2000 23:15:01 +0000
Subject: update fog near/far bug fix

---
 src/mesa/drivers/glide/fxsetup.c | 83 +++++++++++++++++-----------------------
 1 file changed, 36 insertions(+), 47 deletions(-)

(limited to 'src/mesa/drivers/glide/fxsetup.c')

diff --git a/src/mesa/drivers/glide/fxsetup.c b/src/mesa/drivers/glide/fxsetup.c
index 6ebd037fd5..8707aed1d0 100644
--- a/src/mesa/drivers/glide/fxsetup.c
+++ b/src/mesa/drivers/glide/fxsetup.c
@@ -66,8 +66,6 @@ static void fxSetupTexture_NoLock(GLcontext *ctx);
 static void fxSetupTexture(GLcontext *ctx);
 static void fxSetupBlend(GLcontext *ctx);
 static void fxSetupDepthTest(GLcontext *ctx);
-static void fxFogTableGenerate(GLcontext *ctx);
-static void fxSetupFog(GLcontext *ctx, GLboolean forceTableRebuild);
 static void fxSetupScissor(GLcontext *ctx);
 static void fxSetupCull(GLcontext *ctx);
 static void gl_print_fx_state_flags( const char *msg, GLuint flags);
@@ -1424,67 +1422,58 @@ static void fxSetupColorMask(GLcontext *ctx)
 /**************************** Fog Mode SetUp ****************************/
 /************************************************************************/
 
-static void fxFogTableGenerate(GLcontext *ctx)
+/*
+ * This is called during state update in order to update the Glide fog state.
+ */
+static void fxSetupFog(GLcontext *ctx)
 {
-  int i;
-  float f,eyez;
-  fxMesaContext fxMesa=(fxMesaContext)ctx->DriverCtx;
-
-  for(i=0;i<FX_grGetInteger(FX_FOG_TABLE_ENTRIES);i++) {
-    eyez=guFogTableIndexToW(i);
-
-    switch(ctx->Fog.Mode) {
-    case GL_LINEAR:
-      f=(ctx->Fog.End-eyez)/(ctx->Fog.End-ctx->Fog.Start);
-      break;
-    case GL_EXP:
-      f=exp(-ctx->Fog.Density*eyez);  
-      break;
-    case GL_EXP2:
-      f=exp(-ctx->Fog.Density*ctx->Fog.Density*eyez*eyez);
-      break;
-    default: /* That should never happen */
-      f=0.0f;
-      break; 
-    }
+  if (ctx->Fog.Enabled && ctx->FogMode==FOG_FRAGMENT) {
+    fxMesaContext fxMesa = FX_CONTEXT(ctx);
 
-    fxMesa->fogTable[i]=(GrFog_t)((1.0f-CLAMP(f,0.0f,1.0f))*255.0f);
-  }
-}
-
-static void fxSetupFog(GLcontext *ctx, GLboolean forceTableRebuild)
-{
-  fxMesaContext fxMesa=(fxMesaContext)ctx->DriverCtx;
-
-  if(ctx->Fog.Enabled && ctx->FogMode==FOG_FRAGMENT) {
+    /* update fog color */
     GLubyte col[4];
-    FX_grFogMode(GR_FOG_WITH_TABLE);
-
     col[0]=(unsigned int)(255*ctx->Fog.Color[0]);
     col[1]=(unsigned int)(255*ctx->Fog.Color[1]);
     col[2]=(unsigned int)(255*ctx->Fog.Color[2]); 
     col[3]=(unsigned int)(255*ctx->Fog.Color[3]);
-
     FX_grFogColorValue(FXCOLOR4(col));
 
-    if(forceTableRebuild ||
-       (fxMesa->fogTableMode!=ctx->Fog.Mode) ||
-       (fxMesa->fogDensity!=ctx->Fog.Density)) {
-      fxFogTableGenerate(ctx);
-         
-      fxMesa->fogTableMode=ctx->Fog.Mode;
-      fxMesa->fogDensity=ctx->Fog.Density;
+    if(fxMesa->fogTableMode != ctx->Fog.Mode ||
+       fxMesa->fogDensity != ctx->Fog.Density ||
+       fxMesa->fogStart != ctx->Fog.Start ||
+       fxMesa->fogEnd != ctx->Fog.End) {
+      /* reload the fog table */
+      switch (ctx->Fog.Mode) {
+        case GL_LINEAR:
+          guFogGenerateLinear(fxMesa->fogTable, ctx->Fog.Start, ctx->Fog.End);
+          break;
+        case GL_EXP:
+          guFogGenerateExp(fxMesa->fogTable, ctx->Fog.Density);
+          break;
+        case GL_EXP2:
+          guFogGenerateExp2(fxMesa->fogTable, ctx->Fog.Density);
+          break;
+        default:
+          ;
+      }
+      fxMesa->fogTableMode = ctx->Fog.Mode;
+      fxMesa->fogDensity = ctx->Fog.Density;
+      fxMesa->fogStart = ctx->Fog.Start;
+      fxMesa->fogEnd = ctx->Fog.End;
     }
-      
+
     FX_grFogTable(fxMesa->fogTable);
-  } else
+    FX_grFogMode(GR_FOG_WITH_TABLE);
+  }
+  else {
     FX_grFogMode(GR_FOG_DISABLE);
+  }
 }
 
 void fxDDFogfv( GLcontext *ctx, GLenum pname, const GLfloat *params )
 {
    FX_CONTEXT(ctx)->new_state |= FX_NEW_FOG;
-   ctx->Driver.RenderStart = fxSetupFXUnits;
+   ctx->Driver.RenderStart = fxSetupFXUnits;  /* XXX why is this here? */
 }
 
 /************************************************************************/
@@ -1823,7 +1812,7 @@ void fxSetupFXUnits( GLcontext *ctx )
 	fxSetupDepthTest(ctx);
 
      if (newstate & FX_NEW_FOG)
-	fxSetupFog(ctx,GL_FALSE);
+	fxSetupFog(ctx);
 
      if (newstate & FX_NEW_SCISSOR)
 	fxSetupScissor(ctx);
-- 
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