gnome-shell/src/shell-glsl-effect.c
Florian Müllner 007d305736 shell: Actually make GLSLEffect an effect
A generic, introspectable Shader effect is not only more flexible
than a shader actor, it will also make it much easier to turn
Lightbox into an actor subclass and replace Tweener with Clutter's
own animation support.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/651
2019-07-29 17:51:14 +02:00

241 lines
7.7 KiB
C

/* -*- 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;
gint tex_width;
gint tex_height;
};
G_DEFINE_TYPE_WITH_PRIVATE (ShellGLSLEffect, shell_glsl_effect, CLUTTER_TYPE_OFFSCREEN_EFFECT);
static gboolean
shell_glsl_effect_pre_paint (ClutterEffect *effect)
{
ShellGLSLEffect *self = SHELL_GLSL_EFFECT (effect);
ClutterOffscreenEffect *offscreen_effect = CLUTTER_OFFSCREEN_EFFECT (effect);
ShellGLSLEffectPrivate *priv = shell_glsl_effect_get_instance_private (self);
ClutterEffectClass *parent_class;
CoglHandle texture;
gboolean success;
if (!clutter_actor_meta_get_enabled (CLUTTER_ACTOR_META (effect)))
return FALSE;
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;
}
parent_class = CLUTTER_EFFECT_CLASS (shell_glsl_effect_parent_class);
success = parent_class->pre_paint (effect);
if (!success)
return FALSE;
texture = clutter_offscreen_effect_get_texture (offscreen_effect);
priv->tex_width = cogl_texture_get_width (texture);
priv->tex_height = cogl_texture_get_height (texture);
cogl_pipeline_set_layer_texture (priv->pipeline, 0, texture);
return TRUE;
}
static void
shell_glsl_effect_paint_target (ClutterOffscreenEffect *effect)
{
ShellGLSLEffect *self = SHELL_GLSL_EFFECT (effect);
ShellGLSLEffectPrivate *priv;
ClutterActor *actor;
guint8 paint_opacity;
priv = shell_glsl_effect_get_instance_private (self);
actor = clutter_actor_meta_get_actor (CLUTTER_ACTOR_META (effect));
paint_opacity = clutter_actor_get_paint_opacity (actor);
cogl_pipeline_set_color4ub (priv->pipeline,
paint_opacity,
paint_opacity,
paint_opacity,
paint_opacity);
cogl_framebuffer_draw_rectangle (cogl_get_draw_framebuffer (),
priv->pipeline,
0, 0,
priv->tex_width, priv->tex_height);
}
/**
* shell_glsl_effect_add_glsl_snippet:
* @effect: a #ShellGLSLEffect
* @hook: where to insert the code
* @declarations: GLSL declarations
* @code: GLSL code
* @is_replace: wheter 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)
{
ClutterEffectClass *effect_class = CLUTTER_EFFECT_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterOffscreenEffectClass *offscreen_class;
offscreen_class = CLUTTER_OFFSCREEN_EFFECT_CLASS (klass);
offscreen_class->paint_target = shell_glsl_effect_paint_target;
effect_class->pre_paint = shell_glsl_effect_pre_paint;
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);
}