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-rw-r--r--src/mesa/tnl/t_vb_fog.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/src/mesa/tnl/t_vb_fog.c b/src/mesa/tnl/t_vb_fog.c
index bbbf54baac..34f1e811cc 100644
--- a/src/mesa/tnl/t_vb_fog.c
+++ b/src/mesa/tnl/t_vb_fog.c
@@ -1,9 +1,8 @@
-
/*
* Mesa 3-D graphics library
- * Version: 5.1
+ * Version: 6.1
*
- * Copyright (C) 1999-2003 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2004 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"),
@@ -83,8 +82,15 @@ static void init_static_data( void )
}
-static void make_win_fog_coords( GLcontext *ctx, GLvector4f *out,
- const GLvector4f *in )
+/**
+ * Compute per-vertex fog blend factors from fog coordinates by
+ * evaluating the GL_LINEAR, GL_EXP or GL_EXP2 fog function.
+ * Fog coordinates are distances from the eye (typically between the
+ * near and far clip plane distances).
+ * Fog blend factors are in the range [0,1].
+ */
+static void compute_fog_blend_factors( GLcontext *ctx, GLvector4f *out,
+ const GLvector4f *in )
{
GLfloat end = ctx->Fog.End;
GLfloat *v = in->start;
@@ -184,7 +190,8 @@ static GLboolean run_fog_stage( GLcontext *ctx,
VB->FogCoordPtr = &store->fogcoord;
}
- make_win_fog_coords( ctx, VB->FogCoordPtr, input );
+ /* compute blend factors from fog coordinates */
+ compute_fog_blend_factors( ctx, VB->FogCoordPtr, input );
VB->AttribPtr[_TNL_ATTRIB_FOG] = VB->FogCoordPtr;
return GL_TRUE;