gnome-shell/src/shell-glsl-quad.c

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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/**
* SECTION:shell-glsl-quad
* @short_description: Draw a rectangle using GLSL
*
* A #ShellGLSLQuad draws one single rectangle, sized to the allocation
* box, but allows running custom GLSL to the vertex and fragment
* stages of the graphic pipeline.
*
* To ease writing the shader, a single texture layer is also used.
*/
#include "config.h"
#include <cogl/cogl.h>
#include "shell-glsl-quad.h"
typedef struct _ShellGLSLQuadPrivate ShellGLSLQuadPrivate;
struct _ShellGLSLQuadPrivate
{
CoglPipeline *pipeline;
};
G_DEFINE_TYPE_WITH_PRIVATE (ShellGLSLQuad, shell_glsl_quad, CLUTTER_TYPE_ACTOR);
static gboolean
shell_glsl_quad_get_paint_volume (ClutterActor *actor,
ClutterPaintVolume *volume)
{
return clutter_paint_volume_set_from_allocation (volume, actor);
}
static void
shell_glsl_quad_paint (ClutterActor *actor)
{
ShellGLSLQuad *self = SHELL_GLSL_QUAD (actor);
ShellGLSLQuadPrivate *priv;
guint8 paint_opacity;
ClutterActorBox box;
priv = shell_glsl_quad_get_instance_private (self);
paint_opacity = clutter_actor_get_paint_opacity (actor);
clutter_actor_get_allocation_box (actor, &box);
cogl_pipeline_set_color4ub (priv->pipeline,
paint_opacity,
paint_opacity,
paint_opacity,
paint_opacity);
cogl_framebuffer_draw_rectangle (cogl_get_draw_framebuffer (),
priv->pipeline,
box.x1, box.y1,
box.x2, box.y2);
}
/**
* shell_glsl_quad_add_glsl_snippet:
* @quad: a #ShellGLSLQuad
* @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 actor texture.
* See #CoglSnippet for details.
*
* This is only valid inside the a call to the build_pipeline() virtual
* function.
*/
void
shell_glsl_quad_add_glsl_snippet (ShellGLSLQuad *quad,
ShellSnippetHook hook,
const char *declarations,
const char *code,
gboolean is_replace)
{
ShellGLSLQuadClass *klass = SHELL_GLSL_QUAD_GET_CLASS (quad);
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_quad_dispose (GObject *gobject)
{
ShellGLSLQuad *self = SHELL_GLSL_QUAD (gobject);
ShellGLSLQuadPrivate *priv;
priv = shell_glsl_quad_get_instance_private (self);
g_clear_pointer (&priv->pipeline, cogl_object_unref);
G_OBJECT_CLASS (shell_glsl_quad_parent_class)->dispose (gobject);
}
static void
shell_glsl_quad_init (ShellGLSLQuad *quad)
{
}
static void
shell_glsl_quad_constructed (GObject *object)
{
ShellGLSLQuad *self;
ShellGLSLQuadClass *klass;
ShellGLSLQuadPrivate *priv;
CoglContext *ctx =
clutter_backend_get_cogl_context (clutter_get_default_backend ());
G_OBJECT_CLASS (shell_glsl_quad_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 ShellGLSLQuadClass.
*/
klass = SHELL_GLSL_QUAD_GET_CLASS (object);
self = SHELL_GLSL_QUAD (object);
priv = shell_glsl_quad_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 (priv->pipeline, 0, COGL_TEXTURE_TYPE_2D);
}
static void
shell_glsl_quad_class_init (ShellGLSLQuadClass *klass)
{
ClutterActorClass *actor_class = CLUTTER_ACTOR_CLASS (klass);
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->constructed = shell_glsl_quad_constructed;
gobject_class->dispose = shell_glsl_quad_dispose;
actor_class->get_paint_volume = shell_glsl_quad_get_paint_volume;
actor_class->paint = shell_glsl_quad_paint;
}
/**
* shell_glsl_quad_get_uniform_location:
* @quad: a #ShellGLSLQuad
* @name: the uniform name
*
* Returns: the location of the uniform named @name, that can be
* passed to shell_glsl_quad_set_uniform_float().
*/
int
shell_glsl_quad_get_uniform_location (ShellGLSLQuad *quad,
const char *name)
{
ShellGLSLQuadPrivate *priv = shell_glsl_quad_get_instance_private (quad);
return cogl_pipeline_get_uniform_location (priv->pipeline, name);
}
/**
* shell_glsl_quad_set_uniform_float:
* @quad: a #ShellGLSLQuad
* @uniform: the uniform location (as returned by shell_glsl_quad_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_quad_set_uniform_float (ShellGLSLQuad *quad,
int uniform,
int n_components,
int total_count,
const float *value)
{
ShellGLSLQuadPrivate *priv = shell_glsl_quad_get_instance_private (quad);
cogl_pipeline_set_uniform_float (priv->pipeline, uniform,
n_components, total_count / n_components,
value);
}