mesa: Use bitmask/ffs to iterate enabled lights for ff shader keys.

Replaces a loop that iterates all lights and test
which of them is enabled by a loop only iterating over
the bits set in the enabled bitmask.

v2: Use _mesa_bit_scan{,64} instead of open coding.
v3: Use u_bit_scan{,64} instead of _mesa_bit_scan{,64}.

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

diff --git a/src/mesa/main/ffvertex_prog.c b/src/mesa/main/ffvertex_prog.c
index ecdd0184c86eb40ca4a3272b2aa3b590286d0845..ca725545f01a9cb1b5483fefb8e63831b9f6e1de 100644 (file)
--- a/src/mesa/main/ffvertex_prog.c
+++ b/src/mesa/main/ffvertex_prog.c
@@ -44,6 +44,7 @@
 #include "program/prog_parameter.h"
 #include "program/prog_print.h"
 #include "program/prog_statevars.h"
+#include "util/bitscan.h"
 
 
 /** Max of number of lights and texture coord units */
@@ -148,6 +149,7 @@ static GLboolean check_active_shininess( struct gl_context *ctx,
 static void make_state_key( struct gl_context *ctx, struct state_key *key )
 {
    const struct gl_fragment_program *fp;
+   GLbitfield mask;
    GLuint i;
 
    memset(key, 0, sizeof(struct state_key));
@@ -183,23 +185,23 @@ static void make_state_key( struct gl_context *ctx, struct state_key *key )
         key->light_color_material_mask = ctx->Light._ColorMaterialBitmask;
       }
 
-      for (i = 0; i < MAX_LIGHTS; i++) {
-        struct gl_light *light = &ctx->Light.Light[i];
+      mask = ctx->Light._EnabledLights;
+      while (mask) {
+         const int i = u_bit_scan(&mask);
+         struct gl_light *light = &ctx->Light.Light[i];
 
-        if (light->Enabled) {
-           key->unit[i].light_enabled = 1;
+         key->unit[i].light_enabled = 1;
 
-           if (light->EyePosition[3] == 0.0F)
-              key->unit[i].light_eyepos3_is_zero = 1;
+         if (light->EyePosition[3] == 0.0F)
+            key->unit[i].light_eyepos3_is_zero = 1;
 
-           if (light->SpotCutoff == 180.0F)
-              key->unit[i].light_spotcutoff_is_180 = 1;
+         if (light->SpotCutoff == 180.0F)
+            key->unit[i].light_spotcutoff_is_180 = 1;
 
-           if (light->ConstantAttenuation != 1.0F ||
-               light->LinearAttenuation != 0.0F ||
-               light->QuadraticAttenuation != 0.0F)
-              key->unit[i].light_attenuated = 1;
-        }
+         if (light->ConstantAttenuation != 1.0F ||
+             light->LinearAttenuation != 0.0F ||
+             light->QuadraticAttenuation != 0.0F)
+            key->unit[i].light_attenuated = 1;
       }
 
       if (check_active_shininess(ctx, key, 0)) {