1 files changed, 205 insertions, 0 deletions
diff --git a/src/shell-glsl-effect.c b/src/shell-glsl-effect.c
new file mode 100644
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+++ b/src/shell-glsl-effect.c
@@ -0,0 +1,205 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/**
+ * SECTION:shell-glsl-effect
+ * @short_description: An offscreen effect using GLSL
+ *
+ * A #ShellGLSLEffect is a #ClutterOffscreenEffect that allows
+ * running custom GLSL to the vertex and fragment stages of the
+ * graphic pipeline.
+ */
+
+#include "config.h"
+
+#include <cogl/cogl.h>
+#include "shell-glsl-effect.h"
+
+typedef struct _ShellGLSLEffectPrivate ShellGLSLEffectPrivate;
+struct _ShellGLSLEffectPrivate
+{
+  CoglPipeline  *pipeline;
+};
+
+G_DEFINE_TYPE_WITH_PRIVATE (ShellGLSLEffect, shell_glsl_effect, CLUTTER_TYPE_OFFSCREEN_EFFECT);
+
+static CoglPipeline *
+shell_glsl_effect_create_pipeline (ClutterOffscreenEffect *effect,
+                                   CoglTexture            *texture)
+{
+  ShellGLSLEffect *self = SHELL_GLSL_EFFECT (effect);
+  ShellGLSLEffectPrivate *priv = shell_glsl_effect_get_instance_private (self);
+
+  cogl_pipeline_set_layer_texture (priv->pipeline, 0, texture);
+
+  return cogl_object_ref (priv->pipeline);
+}
+
+/**
+ * shell_glsl_effect_add_glsl_snippet:
+ * @effect: a #ShellGLSLEffect
+ * @hook: where to insert the code
+ * @declarations: GLSL declarations
+ * @code: GLSL code
+ * @is_replace: whether Cogl code should be replaced by the custom shader
+ *
+ * Adds a GLSL snippet to the pipeline used for drawing the effect texture.
+ * See #CoglSnippet for details.
+ *
+ * This is only valid inside the a call to the build_pipeline() virtual
+ * function.
+ */
+void
+shell_glsl_effect_add_glsl_snippet (ShellGLSLEffect  *effect,
+                                    ShellSnippetHook  hook,
+                                    const char       *declarations,
+                                    const char       *code,
+                                    gboolean          is_replace)
+{
+  ShellGLSLEffectClass *klass = SHELL_GLSL_EFFECT_GET_CLASS (effect);
+  CoglSnippet *snippet;
+
+  g_return_if_fail (klass->base_pipeline != NULL);
+
+  if (is_replace)
+    {
+      snippet = cogl_snippet_new ((CoglSnippetHook)hook, declarations, NULL);
+      cogl_snippet_set_replace (snippet, code);
+    }
+  else
+    {
+      snippet = cogl_snippet_new ((CoglSnippetHook)hook, declarations, code);
+    }
+
+  if (hook == SHELL_SNIPPET_HOOK_VERTEX ||
+      hook == SHELL_SNIPPET_HOOK_FRAGMENT)
+    cogl_pipeline_add_snippet (klass->base_pipeline, snippet);
+  else
+    cogl_pipeline_add_layer_snippet (klass->base_pipeline, 0, snippet);
+
+  cogl_object_unref (snippet);
+}
+
+static void
+shell_glsl_effect_dispose (GObject *gobject)
+{
+  ShellGLSLEffect *self = SHELL_GLSL_EFFECT (gobject);
+  ShellGLSLEffectPrivate *priv;
+
+  priv = shell_glsl_effect_get_instance_private (self);
+
+  g_clear_pointer (&priv->pipeline, cogl_object_unref);
+
+  G_OBJECT_CLASS (shell_glsl_effect_parent_class)->dispose (gobject);
+}
+
+static void
+shell_glsl_effect_init (ShellGLSLEffect *effect)
+{
+}
+
+static void
+shell_glsl_effect_constructed (GObject *object)
+{
+  ShellGLSLEffect *self;
+  ShellGLSLEffectClass *klass;
+  ShellGLSLEffectPrivate *priv;
+  CoglContext *ctx =
+    clutter_backend_get_cogl_context (clutter_get_default_backend ());
+
+  G_OBJECT_CLASS (shell_glsl_effect_parent_class)->constructed (object);
+
+  /* Note that, differently from ClutterBlurEffect, we are calling
+     this inside constructed, not init, so klass points to the most-derived
+     GTypeClass, not ShellGLSLEffectClass.
+  */
+  klass = SHELL_GLSL_EFFECT_GET_CLASS (object);
+  self = SHELL_GLSL_EFFECT (object);
+  priv = shell_glsl_effect_get_instance_private (self);
+
+  if (G_UNLIKELY (klass->base_pipeline == NULL))
+    {
+      klass->base_pipeline = cogl_pipeline_new (ctx);
+      cogl_pipeline_set_blend (klass->base_pipeline, "RGBA = ADD (SRC_COLOR * (SRC_COLOR[A]), DST_COLOR * (1-SRC_COLOR[A]))", NULL);
+
+      if (klass->build_pipeline != NULL)
+        klass->build_pipeline (self);
+    }
+
+  priv->pipeline = cogl_pipeline_copy (klass->base_pipeline);
+
+  cogl_pipeline_set_layer_null_texture (klass->base_pipeline, 0);
+}
+
+static void
+shell_glsl_effect_class_init (ShellGLSLEffectClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  ClutterOffscreenEffectClass *offscreen_class;
+
+  offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
+  offscreen_class->create_pipeline = shell_glsl_effect_create_pipeline;
+
+  gobject_class->constructed = shell_glsl_effect_constructed;
+  gobject_class->dispose = shell_glsl_effect_dispose;
+}
+
+/**
+ * shell_glsl_effect_get_uniform_location:
+ * @effect: a #ShellGLSLEffect
+ * @name: the uniform name
+ *
+ * Returns: the location of the uniform named @name, that can be
+ *          passed to shell_glsl_effect_set_uniform_float().
+ */
+int
+shell_glsl_effect_get_uniform_location (ShellGLSLEffect *effect,
+                                        const char      *name)
+{
+  ShellGLSLEffectPrivate *priv = shell_glsl_effect_get_instance_private (effect);
+  return cogl_pipeline_get_uniform_location (priv->pipeline, name);
+}
+
+/**
+ * shell_glsl_effect_set_uniform_float:
+ * @effect: a #ShellGLSLEffect
+ * @uniform: the uniform location (as returned by shell_glsl_effect_get_uniform_location())
+ * @n_components: the number of components in the uniform (eg. 3 for a vec3)
+ * @total_count: the total number of floats in @value
+ * @value: (array length=total_count): the array of floats to set @uniform
+ */
+void
+shell_glsl_effect_set_uniform_float (ShellGLSLEffect *effect,
+                                     int              uniform,
+                                     int              n_components,
+                                     int              total_count,
+                                     const float     *value)
+{
+  ShellGLSLEffectPrivate *priv = shell_glsl_effect_get_instance_private (effect);
+  cogl_pipeline_set_uniform_float (priv->pipeline, uniform,
+                                   n_components, total_count / n_components,
+                                   value);
+}
+
+/**
+ * shell_glsl_effect_set_uniform_matrix:
+ * @effect: a #ShellGLSLEffect
+ * @uniform: the uniform location (as returned by shell_glsl_effect_get_uniform_location())
+ * @transpose: Whether to transpose the matrix
+ * @dimensions: the number of components in the uniform (eg. 3 for a vec3)
+ * @total_count: the total number of floats in @value
+ * @value: (array length=total_count): the array of floats to set @uniform
+ */
+void
+shell_glsl_effect_set_uniform_matrix (ShellGLSLEffect *effect,
+                                      int              uniform,
+                                      gboolean         transpose,
+                                      int              dimensions,
+                                      int              total_count,
+                                      const float     *value)
+{
+  ShellGLSLEffectPrivate *priv = shell_glsl_effect_get_instance_private (effect);
+  cogl_pipeline_set_uniform_matrix (priv->pipeline, uniform,
+                                    dimensions,
+                                    total_count / (dimensions * dimensions),
+                                    transpose, value);
+}