[cogl] Implement COGL_DEBUG=disable-texturing for ARBFp and GLSL fragends

[Neil Roberts <nroberts src gnome org>]

commit c3c080481952b33737bea0b5b1c62b6d3b5763f5
Author: Neil Roberts <neil linux intel com>
Date:   Wed Jun 8 18:03:58 2011 +0100

    Implement COGL_DEBUG=disable-texturing for ARBFp and GLSL fragends
    
    The COGL_DEBUG=disable-texturing debug variable disables texturing in
    the fixed function fragend by not bothering to enable the texture
    targets. This wasn't working for the programmable fragends because the
    texture targets don't need to be enabled to use them. This patch
    modifies the two programmable backends to generate a constant value
    for the texture lookups in the shader when the debug variable is
    given.

 cogl/cogl-pipeline-fragend-arbfp.c |   25 ++++++++++++++++---------
 cogl/cogl-pipeline-fragend-glsl.c  |    9 +++++++++
 2 files changed, 25 insertions(+), 9 deletions(-)
---
diff --git a/cogl/cogl-pipeline-fragend-arbfp.c b/cogl/cogl-pipeline-fragend-arbfp.c
index 18f8553..5878be4 100644
--- a/cogl/cogl-pipeline-fragend-arbfp.c
+++ b/cogl/cogl-pipeline-fragend-arbfp.c
@@ -381,15 +381,22 @@ setup_texture_source (ArbfpProgramState *arbfp_program_state,
 {
   if (!arbfp_program_state->unit_state[unit_index].sampled)
     {
-      g_string_append_printf (arbfp_program_state->source,
-                              "TEMP texel%d;\n"
-                              "TEX texel%d,fragment.texcoord[%d],"
-                              "texture[%d],%s;\n",
-                              unit_index,
-                              unit_index,
-                              unit_index,
-                              unit_index,
-                              gl_target_to_arbfp_string (gl_target));
+      if (G_UNLIKELY (COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_TEXTURING)))
+        g_string_append_printf (arbfp_program_state->source,
+                                "TEMP texel%d;\n"
+                                "MOV texel%d, one;\n",
+                                unit_index,
+                                unit_index);
+      else
+        g_string_append_printf (arbfp_program_state->source,
+                                "TEMP texel%d;\n"
+                                "TEX texel%d,fragment.texcoord[%d],"
+                                "texture[%d],%s;\n",
+                                unit_index,
+                                unit_index,
+                                unit_index,
+                                unit_index,
+                                gl_target_to_arbfp_string (gl_target));
       arbfp_program_state->unit_state[unit_index].sampled = TRUE;
     }
 }
diff --git a/cogl/cogl-pipeline-fragend-glsl.c b/cogl/cogl-pipeline-fragend-glsl.c
index b101ab3..10ac6cb 100644
--- a/cogl/cogl-pipeline-fragend-glsl.c
+++ b/cogl/cogl-pipeline-fragend-glsl.c
@@ -350,6 +350,15 @@ add_texture_lookup (GlslShaderState *glsl_shader_state,
   int unit_index = _cogl_pipeline_layer_get_unit_index (layer);
   const char *target_string, *tex_coord_swizzle;
 
+  if (G_UNLIKELY (COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_TEXTURING)))
+    {
+      g_string_append (glsl_shader_state->source,
+                       "vec4 (1.0, 1.0, 1.0, 1.0).");
+      g_string_append (glsl_shader_state->source, swizzle);
+
+      return;
+    }
+
   texture = _cogl_pipeline_layer_get_texture (layer);
 
   if (texture == COGL_INVALID_HANDLE)