From 2caf9e0f59458666f2e5ba4fc1edfb4f6e85e743 Mon Sep 17 00:00:00 2001
From: Robert Bragg <robert@linux.intel.com>
Date: Tue, 3 Jan 2012 11:42:42 +0000
Subject: [PATCH] glsl: always emit sampler uniforms for non NULL layers

There might be custom hooks that want to sample arbitrary layers
even though they aren't referenced as part of the auto generated layer
combine code. This ensures the sampler uniforms are always output for
non-null layers so at least these can be used.

We may consider changing this later to always emit a wrapper
cogl_sampleX() function for each layer so all samples of a layer can
consistently be modified by a COGL_SNIPPET_HOOK_TEXTURE_LOOKUP hook.

Reviewed-by: Neil Roberts <neil@linux.intel.com>
---
 cogl/cogl-pipeline-fragend-glsl.c | 92 ++++++++++++++++++++-----------
 cogl/cogl-pipeline-progend-glsl.c |  2 +-
 2 files changed, 61 insertions(+), 33 deletions(-)

diff --git a/cogl/cogl-pipeline-fragend-glsl.c b/cogl/cogl-pipeline-fragend-glsl.c
index a1885c0b9..ccd0da833 100644
--- a/cogl/cogl-pipeline-fragend-glsl.c
+++ b/cogl/cogl-pipeline-fragend-glsl.c
@@ -372,6 +372,44 @@ add_constant_lookup (CoglPipelineShaderState *shader_state,
                           layer->index, swizzle);
 }
 
+static void
+get_texture_target_string (CoglTextureType texture_type,
+                           const char **target_string_out,
+                           const char **swizzle_out)
+{
+  const char *target_string, *tex_coord_swizzle;
+
+  switch (texture_type)
+    {
+#if 0 /* TODO */
+    case COGL_TEXTURE_TYPE_1D:
+      target_string = "1D";
+      tex_coord_swizzle = "s";
+      break;
+#endif
+
+    case COGL_TEXTURE_TYPE_2D:
+      target_string = "2D";
+      tex_coord_swizzle = "st";
+      break;
+
+    case COGL_TEXTURE_TYPE_3D:
+      target_string = "3D";
+      tex_coord_swizzle = "stp";
+      break;
+
+    case COGL_TEXTURE_TYPE_RECTANGLE:
+      target_string = "2DRect";
+      tex_coord_swizzle = "st";
+      break;
+    }
+
+  if (target_string_out)
+    *target_string_out = target_string;
+  if (swizzle_out)
+    *swizzle_out = tex_coord_swizzle;
+}
+
 static void
 ensure_texture_lookup_generated (CoglPipelineShaderState *shader_state,
                                  CoglPipeline *pipeline,
@@ -424,37 +462,9 @@ ensure_texture_lookup_generated (CoglPipelineShaderState *shader_state,
         _cogl_pipeline_layer_get_texture_type (layer);
       const char *target_string, *tex_coord_swizzle;
 
-      switch (texture_type)
-        {
-#if 0 /* TODO */
-        case COGL_TEXTURE_TYPE_1D:
-          target_string = "1D";
-          tex_coord_swizzle = "s";
-          break;
-#endif
-
-        case COGL_TEXTURE_TYPE_2D:
-          target_string = "2D";
-          tex_coord_swizzle = "st";
-          break;
-
-        case COGL_TEXTURE_TYPE_3D:
-          target_string = "3D";
-          tex_coord_swizzle = "stp";
-          break;
-
-        case COGL_TEXTURE_TYPE_RECTANGLE:
-          target_string = "2DRect";
-          tex_coord_swizzle = "st";
-          break;
-        }
-
-      /* Create a sampler uniform */
-      if (G_LIKELY (!COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_TEXTURING)))
-        g_string_append_printf (shader_state->header,
-                                "uniform sampler%s _cogl_sampler_%i;\n",
-                                target_string,
-                                layer->index);
+      get_texture_target_string (texture_type,
+                                 &target_string,
+                                 &tex_coord_swizzle);
 
       g_string_append_printf (shader_state->header,
                               "vec4\n"
@@ -468,7 +478,7 @@ ensure_texture_lookup_generated (CoglPipelineShaderState *shader_state,
                          "vec4 (1.0, 1.0, 1.0, 1.0);\n");
       else
         g_string_append_printf (shader_state->header,
-                                "texture%s (_cogl_sampler_%i, coords.%s);\n",
+                                "texture%s (cogl_sampler%i, coords.%s);\n",
                                 target_string, layer->index, tex_coord_swizzle);
 
       g_string_append (shader_state->header, "}\n");
@@ -1014,6 +1024,24 @@ _cogl_pipeline_fragend_glsl_end (CoglPipeline *pipeline,
           CoglPipelineLayer *last_layer;
           LayerData *layer_data, *tmp;
 
+          /* We always emit sampler uniforms in case there will be custom
+           * layer snippets that want to sample arbitrary layers. */
+
+          COGL_LIST_FOREACH (layer_data, &shader_state->layers, list_node)
+            {
+              CoglPipelineLayer *layer = layer_data->layer;
+              CoglTextureType texture_type =
+                _cogl_pipeline_layer_get_texture_type (layer);
+              const char *target_string;
+
+              get_texture_target_string (texture_type, &target_string, NULL);
+
+              g_string_append_printf (shader_state->header,
+                                      "uniform sampler%s cogl_sampler%i;\n",
+                                      target_string,
+                                      layer->index);
+            }
+
           last_layer = COGL_LIST_FIRST (&shader_state->layers)->layer;
 
           ensure_layer_generated (pipeline, last_layer->index);
diff --git a/cogl/cogl-pipeline-progend-glsl.c b/cogl/cogl-pipeline-progend-glsl.c
index a0153a6e9..b03c0ec2d 100644
--- a/cogl/cogl-pipeline-progend-glsl.c
+++ b/cogl/cogl-pipeline-progend-glsl.c
@@ -371,7 +371,7 @@ get_uniform_cb (CoglPipeline *pipeline,
      the program has now been linked */
   g_string_set_size (ctx->codegen_source_buffer, 0);
   g_string_append_printf (ctx->codegen_source_buffer,
-                          "_cogl_sampler_%i", layer_index);
+                          "cogl_sampler%i", layer_index);
 
   GE_RET( uniform_location,
           ctx, glGetUniformLocation (state->gl_program,