[gnome-color-manager] Add some GLSL demo code that uses a 3D texture

[Richard Hughes <rhughes src gnome org>]

commit 2aea55c3727b55f1c389b4748d16ee602fa403ec
Author: Richard Hughes <richard hughsie com>
Date:   Mon Jul 5 17:26:18 2010 +0100

    Add some GLSL demo code that uses a 3D texture

 src/.gitignore      |    2 +-
 src/gcm-glsl-demo.c |  179 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 180 insertions(+), 1 deletions(-)
---
diff --git a/src/.gitignore b/src/.gitignore
index 1010e14..133d6d8 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -17,4 +17,4 @@ gcm-fix-profile
 gcm-self-test
 gcm-install-system-wide
 gcm-helper-exiv
-
+gcm-glsl-demo
diff --git a/src/gcm-glsl-demo.c b/src/gcm-glsl-demo.c
new file mode 100644
index 0000000..c68c379
--- /dev/null
+++ b/src/gcm-glsl-demo.c
@@ -0,0 +1,179 @@
+#include <clutter/clutter.h>
+#include <lcms2.h>
+
+#define TESTDATADIR "../data/tests"
+
+//gcc -o gcm-glsl-demo gcm-glsl-demo.c `pkg-config --cflags --libs gtk+-2.0 clutter-x11-1.0 lcms2` -Wall -Wuninitialized -lm -Werror -g -fexceptions && ./gcm-glsl-demo
+
+/* the texture will be 16x16x16 and 3bpp */
+#define GCM_GLSL_LOOKUP_SIZE 	16
+
+static const char fragment_shader_source[] =
+	"uniform sampler2D main_texture;\n"
+	"uniform sampler3D color_data;\n"
+	"\n"
+	"void\n"
+	"main ()\n"
+	"{\n"
+	"	vec3 tex_color = texture2D (main_texture, gl_TexCoord[0].st).rgb;\n"
+	"	gl_FragColor = texture3D (color_data, tex_color);\n"
+	"}";
+
+/**
+ * gcm_glsl_error_cb:
+ **/
+static void
+gcm_glsl_error_cb (cmsContext ContextID, cmsUInt32Number errorcode, const char *text)
+{
+	g_warning ("LCMS error %i: %s", errorcode, text);
+}
+
+/**
+ * gcm_glsl_generate_cogl_color_data:
+ **/
+static CoglHandle
+gcm_glsl_generate_cogl_color_data (const gchar *filename, GError **error)
+{
+	CoglHandle tex = NULL;
+	cmsHPROFILE device_profile;
+	cmsHPROFILE srgb_profile;
+	cmsUInt8Number *data;
+	cmsHTRANSFORM transform;
+	guint array_size;
+	guint r, g, b;
+	guint8 *p;
+
+	srgb_profile = cmsCreate_sRGBProfile ();
+	device_profile = cmsOpenProfileFromFile (filename, "r");
+
+	/* create a cube and cut itup into parts */
+	array_size = GCM_GLSL_LOOKUP_SIZE * GCM_GLSL_LOOKUP_SIZE * GCM_GLSL_LOOKUP_SIZE;
+	data = g_new0 (cmsUInt8Number, 3 * array_size);
+	transform = cmsCreateTransform (srgb_profile, TYPE_RGB_8, device_profile, TYPE_RGB_8, INTENT_PERCEPTUAL, 0);
+
+	/* we failed */
+	if (transform == NULL) {
+		g_set_error (error, 1, 0, "could not create transform");
+		goto out;
+	}
+
+	/* create mapping (blue->r, green->t, red->s) */
+	for (p = data, b = 0; b < GCM_GLSL_LOOKUP_SIZE; b++)  {
+		for (g = 0; g < GCM_GLSL_LOOKUP_SIZE; g++) {
+			for (r = 0; r < GCM_GLSL_LOOKUP_SIZE; r++)  {
+				*(p++) = (r * 255) / (GCM_GLSL_LOOKUP_SIZE - 1);
+				*(p++) = (g * 255) / (GCM_GLSL_LOOKUP_SIZE - 1);
+				*(p++) = (b * 255) / (GCM_GLSL_LOOKUP_SIZE - 1);
+			}
+		}
+	}
+
+	cmsDoTransform (transform, data, data, array_size);
+
+	/* creates a cogl texture from the data */
+	tex = cogl_texture_3d_new_from_data (GCM_GLSL_LOOKUP_SIZE, /* width */
+					     GCM_GLSL_LOOKUP_SIZE, /* height */
+					     GCM_GLSL_LOOKUP_SIZE, /* depth */
+					     COGL_TEXTURE_NO_AUTO_MIPMAP,
+					     COGL_PIXEL_FORMAT_RGB_888,
+					     COGL_PIXEL_FORMAT_ANY,
+					     /* data is tightly packed so we can pass zero */
+					     0, 0,
+					     data, error);
+out:
+	cmsCloseProfile (device_profile);
+	cmsCloseProfile (srgb_profile);
+	if (transform != NULL)
+		cmsDeleteTransform (transform);
+	g_free (data);
+	return tex;
+}
+
+/**
+ * main:
+ **/
+int
+main (int argc, char **argv)
+{
+	ClutterActor *stage, *actor;
+	GError *error = NULL;
+	CoglHandle material;
+	CoglHandle color_data;
+	ClutterShader *shader;
+	ClutterInitError init_error;
+	ClutterColor stage_color = { 0x00, 0x00, 0x00, 0xff };
+	ClutterColor actor_color = { 0xff, 0xff, 0xff, 0x99 };
+
+	init_error = clutter_init (&argc, &argv);
+	if (init_error != CLUTTER_INIT_SUCCESS) {
+		g_warning ("failed to startup clutter: %i", init_error);
+		return 0;
+	}
+	cmsSetLogErrorHandler (gcm_glsl_error_cb);
+
+	/* create a regular texture containing the image */
+	actor = clutter_texture_new_from_file (TESTDATADIR "/image-widget-good.png", &error);
+	if (actor == NULL) {
+		g_warning ("Failed to load texture: %s", error->message);
+		g_clear_error (&error);
+		return 0;
+	}
+
+	/* modify this material so we can add the 3D color data */
+	material = clutter_texture_get_cogl_material (CLUTTER_TEXTURE (actor));
+
+	color_data = gcm_glsl_generate_cogl_color_data (TESTDATADIR "/microsoft-blue-green-reverse.icc", &error);
+	if (color_data == COGL_INVALID_HANDLE) {
+		g_warning ("Error creating lookup texture: %s", error->message);
+		g_clear_error (&error);
+	} else {
+		/* add the texture into the second layer of the material */
+		cogl_material_set_layer (material, 1, color_data);
+
+		/* we want to use linear interpolation for the texture */
+		cogl_material_set_layer_filters (material, 1,
+						 COGL_MATERIAL_FILTER_LINEAR,
+						 COGL_MATERIAL_FILTER_LINEAR);
+
+		/* clamp to the maximum values */
+		cogl_material_set_layer_wrap_mode (material, 1,
+						   COGL_MATERIAL_WRAP_MODE_CLAMP_TO_EDGE);
+
+		cogl_handle_unref (color_data);
+	}
+
+	/* we can set a shader on the actor using the Clutter shader API */
+	shader = clutter_shader_new ();
+	clutter_shader_set_fragment_source (shader, fragment_shader_source, -1);
+	if (clutter_shader_compile (shader, &error)) {
+		/* tell the uniforms which units these are in */
+		clutter_actor_set_shader (actor, shader);
+		clutter_actor_set_shader_param_int (actor, "main_texture", 0);
+		clutter_actor_set_shader_param_int (actor, "color_data", 1);
+	} else {
+		g_warning ("Failed to compile shader: %s", error->message);
+		g_clear_error (&error);
+	}
+	g_object_unref (shader);
+
+	/* setup stage */
+	stage = clutter_stage_get_default ();
+	clutter_actor_set_size (stage, 300, 370);
+	clutter_stage_set_color (CLUTTER_STAGE (stage), &stage_color);
+
+	/* we can just drop the texture on the stage and let it paint normally */
+	clutter_container_add_actor (CLUTTER_CONTAINER (stage), actor);
+
+	/* title */
+	ClutterActor *label = clutter_text_new_full ("Sans 12", "GLSL Shader Demo", &actor_color);
+	clutter_actor_set_size (label, 500, 500);
+	clutter_actor_set_position (label, 20, 320);
+	clutter_container_add_actor (CLUTTER_CONTAINER (stage), label);
+	clutter_actor_show (label);
+
+	clutter_actor_show (stage);
+
+	clutter_main ();
+
+	return 0;
+}