[Mesa-dev] [PATCH] st/mesa: exit the update fragment samplers/textures loops early.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

If we have no more enabled samplers and we've reset all the previously
used ones, no need to keep going around this loop.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/mesa/state_tracker/st_atom_sampler.c |   12 ++++++++----
 src/mesa/state_tracker/st_atom_texture.c |   12 +++++++++---
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
index 8845fed..6524949 100644
--- a/src/mesa/state_tracker/st_atom_sampler.c
+++ b/src/mesa/state_tracker/st_atom_sampler.c
@@ -233,15 +233,16 @@ update_fragment_samplers(struct st_context *st)
    const struct gl_context *ctx = st->ctx;
    struct gl_fragment_program *fprog = ctx->FragmentProgram._Current;
    GLuint su;
+   GLuint samplers_used = fprog->Base.SamplersUsed;
+   GLuint old_max = st->state.num_samplers;
 
    st->state.num_samplers = 0;
 
    /* loop over sampler units (aka tex image units) */
-   for (su = 0; su < ctx->Const.MaxTextureImageUnits; su++) {
+   for (su = 0; su < ctx->Const.MaxTextureImageUnits; su++, samplers_used >>= 1) {
       struct pipe_sampler_state *sampler = st->state.samplers + su;
 
-
-      if (fprog->Base.SamplersUsed & (1 << su)) {
+      if (samplers_used & 1) {
          GLuint texUnit;
 
 	 texUnit = fprog->Base.SamplerUnits[su];
@@ -253,7 +254,10 @@ update_fragment_samplers(struct st_context *st)
          /*printf("%s su=%u non-null\n", __FUNCTION__, su);*/
          cso_single_sampler(st->cso_context, su, sampler);
       }
-      else {
+      else if (samplers_used == 0 && su >= old_max) {
+         /* if we've reset all the old views and we have no more new ones */
+         break;
+      } else {
          /*printf("%s su=%u null\n", __FUNCTION__, su);*/
          cso_single_sampler(st->cso_context, su, NULL);
       }
diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
index d241527..9e98d7f 100644
--- a/src/mesa/state_tracker/st_atom_texture.c
+++ b/src/mesa/state_tracker/st_atom_texture.c
@@ -300,13 +300,16 @@ update_fragment_textures(struct st_context *st)
    const struct gl_context *ctx = st->ctx;
    struct gl_fragment_program *fprog = ctx->FragmentProgram._Current;
    GLuint su;
+   int old_max = st->state.num_textures;
+   GLbitfield samplers_used = fprog->Base.SamplersUsed;
 
    st->state.num_textures = 0;
 
    /* loop over sampler units (aka tex image units) */
-   for (su = 0; su < ctx->Const.MaxTextureImageUnits; su++) {
+   for (su = 0; su < ctx->Const.MaxTextureImageUnits; su++, samplers_used >>= 1) {
       struct pipe_sampler_view *sampler_view = NULL;
-      if (fprog->Base.SamplersUsed & (1 << su)) {
+
+      if (samplers_used & 1) {
          GLboolean retval;
          GLuint texUnit;
 
@@ -317,7 +320,10 @@ update_fragment_textures(struct st_context *st)
 	    continue;
 
          st->state.num_textures = su + 1;
-      }
+      } else if (samplers_used == 0 && su >= old_max)
+         /* if we've reset all the old views and we have no more new ones */
+         break;
+
       pipe_sampler_view_reference(&st->state.sampler_views[su], sampler_view);
    }
 
-- 
1.7.6.5