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-rw-r--r-- | src/shell-invert-lightness-effect.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/src/shell-invert-lightness-effect.c b/src/shell-invert-lightness-effect.c new file mode 100644 index 0000000..f856ede --- /dev/null +++ b/src/shell-invert-lightness-effect.c @@ -0,0 +1,152 @@ +/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ +/* + * Copyright (C) 2010-2012 Inclusive Design Research Centre, OCAD University. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library. If not, see <http://www.gnu.org/licenses/>. + * + * Author: + * Joseph Scheuhammer <clown@alum.mit.edu> + */ + +/** + * SECTION:shell-invert-lightness-effect + * @short_description: A colorization effect where lightness is inverted but + * color is not. + * @see_also: #ClutterEffect, #ClutterOffscreenEffect + * + * #ShellInvertLightnessEffect is a sub-class of #ClutterEffect that enhances + * the appearance of a clutter actor. Specifically it inverts the lightness + * of a #ClutterActor (e.g., darker colors become lighter, white becomes black, + * and white, black). + */ + +#define SHELL_INVERT_LIGHTNESS_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), SHELL_TYPE_INVERT_LIGHTNESS_EFFECT, ShellInvertLightnessEffectClass)) +#define SHELL_IS_INVERT_EFFECT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), SHELL_TYPE_INVERT_LIGHTNESS_EFFECT)) +#define SHELL_INVERT_LIGHTNESS_EFFECT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), SHELL_TYPE_INVERT_LIGHTNESS_EFFEC, ShellInvertLightnessEffectClass)) + +#include "shell-invert-lightness-effect.h" + +#include <cogl/cogl.h> + +struct _ShellInvertLightnessEffect +{ + ClutterOffscreenEffect parent_instance; + + CoglPipeline *pipeline; +}; + +struct _ShellInvertLightnessEffectClass +{ + ClutterOffscreenEffectClass parent_class; + + CoglPipeline *base_pipeline; +}; + +/* Lightness inversion in GLSL. + */ +static const gchar *invert_lightness_source = + "cogl_texel = texture2D (cogl_sampler, cogl_tex_coord.st);\n" + "vec3 effect = vec3 (cogl_texel);\n" + "\n" + "float maxColor = max (cogl_texel.r, max (cogl_texel.g, cogl_texel.b));\n" + "float minColor = min (cogl_texel.r, min (cogl_texel.g, cogl_texel.b));\n" + "float lightness = (maxColor + minColor) / 2.0;\n" + "\n" + "float delta = (1.0 - lightness) - lightness;\n" + "effect.rgb = (effect.rgb + delta);\n" + "\n" + "cogl_texel = vec4 (effect, cogl_texel.a);\n"; + +G_DEFINE_TYPE (ShellInvertLightnessEffect, + shell_invert_lightness_effect, + CLUTTER_TYPE_OFFSCREEN_EFFECT); + +static CoglPipeline * +shell_glsl_effect_create_pipeline (ClutterOffscreenEffect *effect, + CoglTexture *texture) +{ + ShellInvertLightnessEffect *self = SHELL_INVERT_LIGHTNESS_EFFECT (effect); + + cogl_pipeline_set_layer_texture (self->pipeline, 0, texture); + + return cogl_object_ref (self->pipeline); +} + +static void +shell_invert_lightness_effect_dispose (GObject *gobject) +{ + ShellInvertLightnessEffect *self = SHELL_INVERT_LIGHTNESS_EFFECT (gobject); + + if (self->pipeline != NULL) + { + cogl_object_unref (self->pipeline); + self->pipeline = NULL; + } + + G_OBJECT_CLASS (shell_invert_lightness_effect_parent_class)->dispose (gobject); +} + +static void +shell_invert_lightness_effect_class_init (ShellInvertLightnessEffectClass *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->dispose = shell_invert_lightness_effect_dispose; +} + +static void +shell_invert_lightness_effect_init (ShellInvertLightnessEffect *self) +{ + ShellInvertLightnessEffectClass *klass; + klass = SHELL_INVERT_LIGHTNESS_EFFECT_GET_CLASS (self); + + if (G_UNLIKELY (klass->base_pipeline == NULL)) + { + CoglSnippet *snippet; + CoglContext *ctx = + clutter_backend_get_cogl_context (clutter_get_default_backend ()); + + klass->base_pipeline = cogl_pipeline_new (ctx); + + snippet = cogl_snippet_new (COGL_SNIPPET_HOOK_TEXTURE_LOOKUP, + NULL, + NULL); + cogl_snippet_set_replace (snippet, invert_lightness_source); + cogl_pipeline_add_layer_snippet (klass->base_pipeline, 0, snippet); + cogl_object_unref (snippet); + + cogl_pipeline_set_layer_null_texture (klass->base_pipeline, 0); + } + + self->pipeline = cogl_pipeline_copy (klass->base_pipeline); +} + +/** + * shell_invert_lightness_effect_new: + * + * Creates a new #ShellInvertLightnessEffect to be used with + * clutter_actor_add_effect() + * + * Return value: (transfer full): the newly created + * #ShellInvertLightnessEffect or %NULL. Use g_object_unref() when done. + */ +ClutterEffect * +shell_invert_lightness_effect_new (void) +{ + return g_object_new (SHELL_TYPE_INVERT_LIGHTNESS_EFFECT, NULL); +} |