diff options
| author | Brian Paul <[email protected]> | 2004-02-25 16:14:16 +0000 |
|---|---|---|
| committer | Brian Paul <[email protected]> | 2004-02-25 16:14:16 +0000 |
| commit | 54056db8db4cba5163ef40a30511bbdd35f8a47a (patch) | |
| tree | 51d3ca1af1b878b3be5373555ef011ec781bad4e | |
| parent | 20e25ca50a6335fda3769f746165b5bbc2dfa95b (diff) | |
use ABS(Z) when computing blend factors
| -rw-r--r-- | src/mesa/tnl/t_vb_fog.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/mesa/tnl/t_vb_fog.c b/src/mesa/tnl/t_vb_fog.c index f9646b24f34..cb71e67d2fd 100644 --- a/src/mesa/tnl/t_vb_fog.c +++ b/src/mesa/tnl/t_vb_fog.c @@ -91,6 +91,7 @@ init_static_data( void ) * 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). + * Note the fog (eye Z) coords may be negative so we use ABS(z) below. * Fog blend factors are in the range [0,1]. */ static void @@ -113,7 +114,7 @@ compute_fog_blend_factors(GLcontext *ctx, GLvector4f *out, const GLvector4f *in) else d = 1.0F / (ctx->Fog.End - ctx->Fog.Start); for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) { - const GLfloat z = *v; + const GLfloat z = FABSF(*v); GLfloat f = (end - z) * d; data[i][0] = CLAMP(f, 0.0F, 1.0F); } @@ -121,14 +122,14 @@ compute_fog_blend_factors(GLcontext *ctx, GLvector4f *out, const GLvector4f *in) case GL_EXP: d = ctx->Fog.Density; for ( i = 0 ; i < n ; i++, STRIDE_F(v,stride)) { - const GLfloat z = *v; + const GLfloat z = FABSF(*v); NEG_EXP( data[i][0], d * z ); } break; case GL_EXP2: d = ctx->Fog.Density*ctx->Fog.Density; for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) { - const GLfloat z = *v; + const GLfloat z = FABSF(*v); NEG_EXP( data[i][0], d * z * z ); } break; @@ -170,7 +171,6 @@ run_fog_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage) plane[1] = -m[6]; plane[2] = -m[10]; plane[3] = -m[14]; - /* Full eye coords weren't required, just calculate the * eye Z values. */ |