colorize-effect: Do not inherit from ShaderEffect

See commits:

  7daeb217 blur-effect: Do not inherit from ShaderEffect
  1ec57743 desaturate-effect: Do not inherit from ShaderEffect

We might avoid using shaders at all in the future for simple effects.

clutter/clutter-colorize-effect.c

@@ -30,10 +30,6 @@
  * #ClutterColorizeEffect is a sub-class of #ClutterEffect that
  * colorizes an actor with the given tint.
  *
- * #ClutterColorizeEffect uses the programmable pipeline of the GPU
- * so it is only available on graphics hardware that supports this
- * feature.
- *
  * #ClutterColorizeEffect is available since Clutter 1.4
  */
 
@@ -51,25 +47,33 @@
 
 #include "clutter-debug.h"
 #include "clutter-enum-types.h"
+#include "clutter-offscreen-effect.h"
 #include "clutter-private.h"
-#include "clutter-shader-effect.h"
 
 typedef struct _ClutterColorizeEffectClass    ClutterColorizeEffectClass;
 
 struct _ClutterColorizeEffect
 {
-  ClutterShaderEffect parent_instance;
+  ClutterOffscreenEffect parent_instance;
 
   /* a back pointer to our actor, so that we can query it */
   ClutterActor *actor;
 
   /* the tint of the colorization */
   ClutterColor tint;
+
+  CoglHandle shader;
+  CoglHandle program;
+
+  gint tex_uniform;
+  gint tint_uniform;
+
+  guint is_compiled : 1;
 };
 
 struct _ClutterColorizeEffectClass
 {
-  ClutterShaderEffectClass parent_class;
+  ClutterOffscreenEffectClass parent_class;
 };
 
 /* the magic gray vec3 has been taken from the NTSC conversion weights
@@ -106,48 +110,136 @@ static GParamSpec *obj_props[PROP_LAST];
 
 G_DEFINE_TYPE (ClutterColorizeEffect,
                clutter_colorize_effect,
-               CLUTTER_TYPE_SHADER_EFFECT);
+               CLUTTER_TYPE_OFFSCREEN_EFFECT);
 
 static gboolean
 clutter_colorize_effect_pre_paint (ClutterEffect *effect)
 {
   ClutterColorizeEffect *self = CLUTTER_COLORIZE_EFFECT (effect);
-  ClutterShaderEffect *shader_effect;
   ClutterEffectClass *parent_class;
-  float tint_r, tint_g, tint_b;
 
   if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
     return FALSE;
 
-  shader_effect = CLUTTER_SHADER_EFFECT (effect);
+  self->actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
+  if (self->actor == NULL)
+    return FALSE;
 
-  clutter_shader_effect_set_shader_source (shader_effect, colorize_glsl_shader);
+  if (!clutter_feature_available (CLUTTER_FEATURE_SHADERS_GLSL))
+    {
+      /* if we don't have support for GLSL shaders then we
+       * forcibly disable the ActorMeta
+       */
+      g_warning ("Unable to use the ShaderEffect: the graphics hardware "
+                 "or the current GL driver does not implement support "
+                 "for the GLSL shading language.");
+      clutter_actor_meta_set_enabled (CLUTTER_ACTOR_META (effect), FALSE);
+      return FALSE;
+    }
 
-  /* we want normalized values here */
-  tint_r = self->tint.red   / 255.0f;
-  tint_g = self->tint.green / 255.0f;
-  tint_b = self->tint.blue  / 255.0f;
+  if (self->shader == COGL_INVALID_HANDLE)
+    {
+      self->shader = cogl_create_shader (COGL_SHADER_TYPE_FRAGMENT);
+      cogl_shader_source (self->shader, colorize_glsl_shader);
 
-  /* bind the uniforms to the factor property */
-  clutter_shader_effect_set_uniform (shader_effect,
-                                     "tex",
-                                     G_TYPE_INT, 1,
-                                     0);
-  clutter_shader_effect_set_uniform (shader_effect,
-                                     "tint",
-                                     G_TYPE_FLOAT, 3,
-                                     tint_r,
-                                     tint_g,
-                                     tint_b);
+      self->is_compiled = FALSE;
+      self->tex_uniform = -1;
+      self->tint_uniform = -1;
+    }
+
+  if (self->program == COGL_INVALID_HANDLE)
+    self->program = cogl_create_program ();
+
+  if (!self->is_compiled)
+    {
+      g_assert (self->shader != COGL_INVALID_HANDLE);
+      g_assert (self->program != COGL_INVALID_HANDLE);
+
+      cogl_shader_compile (self->shader);
+      if (!cogl_shader_is_compiled (self->shader))
+        {
+          gchar *log_buf = cogl_shader_get_info_log (self->shader);
+
+          g_warning (G_STRLOC ": Unable to compile the colorize shader: %s",
+                     log_buf);
+          g_free (log_buf);
+
+          cogl_handle_unref (self->shader);
+          cogl_handle_unref (self->program);
+
+          self->shader = COGL_INVALID_HANDLE;
+          self->program = COGL_INVALID_HANDLE;
+        }
+      else
+        {
+          cogl_program_attach_shader (self->program, self->shader);
+          cogl_program_link (self->program);
+
+          cogl_handle_unref (self->shader);
+
+          self->is_compiled = TRUE;
+
+          self->tex_uniform =
+            cogl_program_get_uniform_location (self->program, "tex");
+          self->tint_uniform =
+            cogl_program_get_uniform_location (self->program, "tint");
+        }
+    }
 
   parent_class = CLUTTER_EFFECT_CLASS (clutter_colorize_effect_parent_class);
   return parent_class->pre_paint (effect);
 }
 
 static void
-clutter_colorize_effect_finalize (GObject *gobject)
+clutter_colorize_effect_paint_target (ClutterOffscreenEffect *effect)
 {
-  G_OBJECT_CLASS (clutter_colorize_effect_parent_class)->finalize (gobject);
+  ClutterColorizeEffect *self = CLUTTER_COLORIZE_EFFECT (effect);
+  ClutterOffscreenEffectClass *parent;
+  CoglHandle material;
+
+  if (self->program == COGL_INVALID_HANDLE)
+    goto out;
+
+  cogl_program_use (self->program);
+
+  if (self->tex_uniform > -1)
+    cogl_program_uniform_1i (self->tex_uniform, 0);
+
+  if (self->tint_uniform > -1)
+    {
+      float tint[3] = {
+        self->tint.red / 255.0,
+        self->tint.green / 255.0,
+        self->tint.blue / 255.0
+      };
+
+      cogl_program_uniform_float (self->tint_uniform, 3, 1, tint);
+    }
+
+  cogl_program_use (COGL_INVALID_HANDLE);
+
+  material = clutter_offscreen_effect_get_target (effect);
+  cogl_material_set_user_program (material, self->program);
+
+out:
+  parent = CLUTTER_OFFSCREEN_EFFECT_CLASS (clutter_colorize_effect_parent_class);
+  parent->paint_target (effect);
+}
+
+static void
+clutter_colorize_effect_dispose (GObject *gobject)
+{
+  ClutterColorizeEffect *self = CLUTTER_COLORIZE_EFFECT (gobject);
+
+  if (self->program != COGL_INVALID_HANDLE)
+    {
+      cogl_handle_unref (self->program);
+
+      self->program = COGL_INVALID_HANDLE;
+      self->shader = COGL_INVALID_HANDLE;
+    }
+
+  G_OBJECT_CLASS (clutter_colorize_effect_parent_class)->dispose (gobject);
 }
 
 static void
@@ -196,13 +288,17 @@ clutter_colorize_effect_class_init (ClutterColorizeEffectClass *klass)
 {
   ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
   GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  ClutterOffscreenEffectClass *offscreen_class;
   GParamSpec *pspec;
 
+  offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
+  offscreen_class->paint_target = clutter_colorize_effect_paint_target;
+
   effect_class->pre_paint = clutter_colorize_effect_pre_paint;
 
   gobject_class->set_property = clutter_colorize_effect_set_property;
   gobject_class->get_property = clutter_colorize_effect_get_property;
-  gobject_class->finalize = clutter_colorize_effect_finalize;
+  gobject_class->dispose = clutter_colorize_effect_dispose;
 
   /**
    * ClutterColorizeEffect:tint: