mesa: Use bitmask/ffs to iterate enabled lights

Replaces loops that iterate 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 <[email protected]>
Signed-off-by: Mathias Fröhlich <[email protected]>

1 files changed, 6 insertions, 3 deletions

diff --git a/src/mesa/main/rastpos.c b/src/mesa/main/rastpos.c
index b468219e688..8f971f5b8d4 100644
--- a/src/mesa/main/rastpos.c
+++ b/src/mesa/main/rastpos.c
@@ -37,7 +37,7 @@
 #include "state.h"
 #include "main/dispatch.h"
 #include "main/viewport.h"
-#include "util/simple_list.h"
+#include "util/bitscan.h"
 
 
 
@@ -125,7 +125,7 @@ shade_rastpos(struct gl_context *ctx,
               GLfloat Rspec[4])
 {
    /*const*/ GLfloat (*base)[3] = ctx->Light._BaseColor;
-   const struct gl_light *light;
+   GLbitfield mask;
    GLfloat diffuseColor[4], specularColor[4];  /* for RGB mode only */
 
    COPY_3V(diffuseColor, base[0]);
@@ -133,7 +133,10 @@ shade_rastpos(struct gl_context *ctx,
       ctx->Light.Material.Attrib[MAT_ATTRIB_FRONT_DIFFUSE][3], 0.0F, 1.0F );
    ASSIGN_4V(specularColor, 0.0, 0.0, 0.0, 1.0);
 
-   foreach (light, &ctx->Light.EnabledList) {
+   mask = ctx->Light._EnabledLights;
+   while (mask) {
+      const int i = u_bit_scan(&mask);
+      struct gl_light *light = &ctx->Light.Light[i];
       GLfloat attenuation = 1.0;
       GLfloat VP[3]; /* vector from vertex to light pos */
       GLfloat n_dot_VP;