1 files changed, 43 insertions, 16 deletions

diff --git a/src/mesa/shader/shader_api.c b/src/mesa/shader/shader_api.c
index ce196493231..453cd3964af 100644
--- a/src/mesa/shader/shader_api.c
+++ b/src/mesa/shader/shader_api.c
@@ -390,6 +390,8 @@ get_shader_flags(void)
          flags |= GLSL_OPT;
       if (_mesa_strstr(env, "uniform"))
          flags |= GLSL_UNIFORMS;
+      if (_mesa_strstr(env, "useprog"))
+         flags |= GLSL_USE_PROG;
    }
 
    return flags;
@@ -1497,6 +1499,41 @@ _mesa_link_program(GLcontext *ctx, GLuint program)
 
 
 /**
+ * Print basic shader info (for debug).
+ */
+static void
+print_shader_info(const struct gl_shader_program *shProg)
+{
+   GLuint i;
+
+   _mesa_printf("Mesa: glUseProgram(%u)\n", shProg->Name);
+   for (i = 0; i < shProg->NumShaders; i++) {
+      const char *s;
+      switch (shProg->Shaders[i]->Type) {
+      case GL_VERTEX_SHADER:
+         s = "vertex";
+         break;
+      case GL_FRAGMENT_SHADER:
+         s = "fragment";
+         break;
+      case GL_GEOMETRY_SHADER:
+         s = "geometry";
+         break;
+      default:
+         s = "";
+      }
+      _mesa_printf("  %s shader %u, checksum %u\n", s, 
+                   shProg->Shaders[i]->Name,
+                   shProg->Shaders[i]->SourceChecksum);
+   }
+   if (shProg->VertexProgram)
+      _mesa_printf("  vert prog %u\n", shProg->VertexProgram->Base.Id);
+   if (shProg->FragmentProgram)
+      _mesa_printf("  frag prog %u\n", shProg->FragmentProgram->Base.Id);
+}
+
+
+/**
  * Called via ctx->Driver.UseProgram()
  */
 void
@@ -1510,8 +1547,6 @@ _mesa_use_program(GLcontext *ctx, GLuint program)
       return;
    }
 
-   FLUSH_VERTICES(ctx, _NEW_PROGRAM | _NEW_PROGRAM_CONSTANTS);
-
    if (program) {
       shProg = _mesa_lookup_shader_program_err(ctx, program, "glUseProgram");
       if (!shProg) {
@@ -1524,26 +1559,18 @@ _mesa_use_program(GLcontext *ctx, GLuint program)
       }
 
       /* debug code */
-      if (0) {
-         GLuint i;
-         _mesa_printf("Use Shader %u\n", shProg->Name);
-         for (i = 0; i < shProg->NumShaders; i++) {
-            _mesa_printf(" shader %u, type 0x%x, checksum %u\n",
-                         shProg->Shaders[i]->Name,
-                         shProg->Shaders[i]->Type,
-                         shProg->Shaders[i]->SourceChecksum);
-         }
-         if (shProg->VertexProgram)
-            printf(" vert prog %u\n", shProg->VertexProgram->Base.Id);
-         if (shProg->FragmentProgram)
-            printf(" frag prog %u\n", shProg->FragmentProgram->Base.Id);
+      if (ctx->Shader.Flags & GLSL_USE_PROG) {
+         print_shader_info(shProg);
       }
    }
    else {
       shProg = NULL;
    }
 
-   _mesa_reference_shader_program(ctx, &ctx->Shader.CurrentProgram, shProg);
+   if (ctx->Shader.CurrentProgram != shProg) {
+      FLUSH_VERTICES(ctx, _NEW_PROGRAM | _NEW_PROGRAM_CONSTANTS);
+      _mesa_reference_shader_program(ctx, &ctx->Shader.CurrentProgram, shProg);
+   }
 }