mesa: Care for differences in fog mode only if fog is consumed.

In creating fixed function vertex shader hash keys do only
care for producing the varying output if fog is enabled and the
varing is consumed in the fragment stage.

Signed-off-by: Mathias Fröhlich <Mathias.Froehlich@web.de>
Reviewed-by: Brian Paul <brianp@vmware.com>

diff --git a/src/mesa/main/ffvertex_prog.c b/src/mesa/main/ffvertex_prog.c
index 172ab698dbd5aded3a893cfded8fe9ed1e2cf6ad..6d852496e02de7fe0db253fbf759503a309e3205 100644 (file)
--- a/src/mesa/main/ffvertex_prog.c
+++ b/src/mesa/main/ffvertex_prog.c
@@ -222,9 +222,11 @@ static void make_state_key( struct gl_context *ctx, struct state_key *key )
    if (ctx->Transform.RescaleNormals)
       key->rescale_normals = 1;
 
-   key->fog_distance_mode =
-      translate_fog_distance_mode(ctx->Fog.FogCoordinateSource,
-                                  ctx->Fog.FogDistanceMode);
+   /* Only distinguish fog parameters if we actually need */
+   if (key->fragprog_inputs_read & VARYING_BIT_FOGC)
+      key->fog_distance_mode =
+         translate_fog_distance_mode(ctx->Fog.FogCoordinateSource,
+                                     ctx->Fog.FogDistanceMode);
 
    if (ctx->Point._Attenuated)
       key->point_attenuated = 1;