[Mesa-dev] [PATCH 16/31] radeon/r200: Use bitmask/ffs to iterate enabled lights

[Mathias.Froehlich at gmx.net]

From: Mathias Fröhlich <mathias.froehlich at web.de>

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.

Reviewed-by: Brian Paul <brianp at vmware.com>
Signed-off-by: Mathias Fröhlich <Mathias.Froehlich at web.de>
---
 src/mesa/drivers/dri/r200/r200_state.c     | 39 ++++++++++++++--------------
 src/mesa/drivers/dri/radeon/radeon_state.c | 41 +++++++++++++++---------------
 2 files changed, 39 insertions(+), 41 deletions(-)

diff --git a/src/mesa/drivers/dri/r200/r200_state.c b/src/mesa/drivers/dri/r200/r200_state.c
index f0693ba..12efe18 100644
--- a/src/mesa/drivers/dri/r200/r200_state.c
+++ b/src/mesa/drivers/dri/r200/r200_state.c
@@ -1112,27 +1112,26 @@ static void update_light( struct gl_context *ctx )
 
 
    if (ctx->Light.Enabled) {
-      GLint p;
-      for (p = 0 ; p < MAX_LIGHTS; p++) {
-	 if (ctx->Light.Light[p].Enabled) {
-	    struct gl_light *l = &ctx->Light.Light[p];
-	    GLfloat *fcmd = (GLfloat *)R200_DB_STATE( lit[p] );
-
-	    if (l->EyePosition[3] == 0.0) {
-	       COPY_3FV( &fcmd[LIT_POSITION_X], l->_VP_inf_norm );
-	       COPY_3FV( &fcmd[LIT_DIRECTION_X], l->_h_inf_norm );
-	       fcmd[LIT_POSITION_W] = 0;
-	       fcmd[LIT_DIRECTION_W] = 0;
-	    } else {
-	       COPY_4V( &fcmd[LIT_POSITION_X], l->_Position );
-	       fcmd[LIT_DIRECTION_X] = -l->_NormSpotDirection[0];
-	       fcmd[LIT_DIRECTION_Y] = -l->_NormSpotDirection[1];
-	       fcmd[LIT_DIRECTION_Z] = -l->_NormSpotDirection[2];
-	       fcmd[LIT_DIRECTION_W] = 0;
-	    }
+      GLbitfield mask = ctx->Light._EnabledLights;
+      while (mask) {
+         const int p = _mesa_bit_scan(&mask);
+         struct gl_light *l = &ctx->Light.Light[p];
+         GLfloat *fcmd = (GLfloat *)R200_DB_STATE( lit[p] );
+
+         if (l->EyePosition[3] == 0.0) {
+            COPY_3FV( &fcmd[LIT_POSITION_X], l->_VP_inf_norm );
+            COPY_3FV( &fcmd[LIT_DIRECTION_X], l->_h_inf_norm );
+            fcmd[LIT_POSITION_W] = 0;
+            fcmd[LIT_DIRECTION_W] = 0;
+         } else {
+            COPY_4V( &fcmd[LIT_POSITION_X], l->_Position );
+            fcmd[LIT_DIRECTION_X] = -l->_NormSpotDirection[0];
+            fcmd[LIT_DIRECTION_Y] = -l->_NormSpotDirection[1];
+            fcmd[LIT_DIRECTION_Z] = -l->_NormSpotDirection[2];
+            fcmd[LIT_DIRECTION_W] = 0;
+         }
 
-	    R200_DB_STATECHANGE( rmesa, &rmesa->hw.lit[p] );
-	 }
+         R200_DB_STATECHANGE( rmesa, &rmesa->hw.lit[p] );
       }
    }
 }
diff --git a/src/mesa/drivers/dri/radeon/radeon_state.c b/src/mesa/drivers/dri/radeon/radeon_state.c
index 8a1b81d..41a4d04 100644
--- a/src/mesa/drivers/dri/radeon/radeon_state.c
+++ b/src/mesa/drivers/dri/radeon/radeon_state.c
@@ -892,27 +892,26 @@ static void update_light( struct gl_context *ctx )
 
 
    if (ctx->Light.Enabled) {
-      GLint p;
-      for (p = 0 ; p < MAX_LIGHTS; p++) {
-	 if (ctx->Light.Light[p].Enabled) {
-	    struct gl_light *l = &ctx->Light.Light[p];
-	    GLfloat *fcmd = (GLfloat *)RADEON_DB_STATE( lit[p] );
-
-	    if (l->EyePosition[3] == 0.0) {
-	       COPY_3FV( &fcmd[LIT_POSITION_X], l->_VP_inf_norm );
-	       COPY_3FV( &fcmd[LIT_DIRECTION_X], l->_h_inf_norm );
-	       fcmd[LIT_POSITION_W] = 0;
-	       fcmd[LIT_DIRECTION_W] = 0;
-	    } else {
-	       COPY_4V( &fcmd[LIT_POSITION_X], l->_Position );
-	       fcmd[LIT_DIRECTION_X] = -l->_NormSpotDirection[0];
-	       fcmd[LIT_DIRECTION_Y] = -l->_NormSpotDirection[1];
-	       fcmd[LIT_DIRECTION_Z] = -l->_NormSpotDirection[2];
-	       fcmd[LIT_DIRECTION_W] = 0;
-	    }
-
-	    RADEON_DB_STATECHANGE( rmesa, &rmesa->hw.lit[p] );
-	 }
+      GLbitfield mask = ctx->Light._EnabledLights;
+      while (mask) {
+         const int p = _mesa_bit_scan(&mask);
+         struct gl_light *l = &ctx->Light.Light[p];
+         GLfloat *fcmd = (GLfloat *)RADEON_DB_STATE( lit[p] );
+
+         if (l->EyePosition[3] == 0.0) {
+            COPY_3FV( &fcmd[LIT_POSITION_X], l->_VP_inf_norm );
+            COPY_3FV( &fcmd[LIT_DIRECTION_X], l->_h_inf_norm );
+            fcmd[LIT_POSITION_W] = 0;
+            fcmd[LIT_DIRECTION_W] = 0;
+         } else {
+            COPY_4V( &fcmd[LIT_POSITION_X], l->_Position );
+            fcmd[LIT_DIRECTION_X] = -l->_NormSpotDirection[0];
+            fcmd[LIT_DIRECTION_Y] = -l->_NormSpotDirection[1];
+            fcmd[LIT_DIRECTION_Z] = -l->_NormSpotDirection[2];
+            fcmd[LIT_DIRECTION_W] = 0;
+         }
+
+         RADEON_DB_STATECHANGE( rmesa, &rmesa->hw.lit[p] );
       }
    }
 }
-- 
2.5.5