From 9a4ac75dee1e1971b205677da4670ffb94cbcf3a Mon Sep 17 00:00:00 2001
From: Andy Spencer <andy753421@gmail.com>
Date: Mon, 25 Jan 2010 07:36:11 +0000
Subject: [PATCH] Update sorting example to use a shader (broken)

Maybe we can use a shader to make the textures work? Not sure if this is
possible or not..
---
 examples/sorting/sort.c    | 53 ++++++++++++++++++++++++++++++++++++++
 examples/sorting/sort.glsl | 14 ++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 examples/sorting/sort.glsl

diff --git a/examples/sorting/sort.c b/examples/sorting/sort.c
index 7cb54c5..50ccda9 100644
--- a/examples/sorting/sort.c
+++ b/examples/sorting/sort.c
@@ -264,6 +264,56 @@ static guint load_tex(gchar *filename)
 	return tex;
 }
 
+gchar *gl_program_log(guint program, int *_len)
+{
+	gchar *buf = NULL;
+	int len = 0;
+	glGetProgramiv(program, GL_INFO_LOG_LENGTH, &len);
+	if (len > 0) {
+		buf = g_malloc(len);
+		glGetProgramInfoLog(program, len, &len, buf);
+	}
+	if (_len)
+		*_len = len;
+	return buf;
+}
+
+static void load_shader(gchar *filename)
+{
+	gchar *source;
+	gboolean status = g_file_get_contents(filename, &source, NULL, NULL);
+	if (!status)
+		g_error("Failed to load shader");
+
+	guint program = glCreateProgram();
+	if (!program)
+		g_error("Error creating program");
+
+	guint shader = glCreateShader(GL_VERTEX_SHADER_ARB);
+	if (!shader)
+		g_error("Error creating shader");
+
+	glShaderSource(shader, 1, (const gchar**)&source, NULL);
+	if (glGetError())
+		g_error("Error setting shader source");
+
+	glCompileShader(shader);
+	if (glGetError())
+		g_error("Error compiling shader");
+
+	glAttachShader(program, shader);
+	if (glGetError())
+		g_error("Error attaching shader");
+
+	glLinkProgram(program);
+	if (glGetError())
+		g_error("Error linking program");
+
+	glUseProgram(program);
+	if (glGetError())
+		g_error("Error using program:\n%s", gl_program_log(program, NULL));
+}
+
 int main(int argc, char **argv)
 {
 	gtk_init(&argc, &argv);
@@ -289,6 +339,9 @@ int main(int argc, char **argv)
 	/* Load texture */
 	tex = load_tex("flag.png");
 
+	/* Load shader */
+	load_shader("sort.glsl");
+
 	gtk_main();
 
 	gdk_gl_drawable_gl_end(gldrawable);
diff --git a/examples/sorting/sort.glsl b/examples/sorting/sort.glsl
new file mode 100644
index 0000000..500e23b
--- /dev/null
+++ b/examples/sorting/sort.glsl
@@ -0,0 +1,14 @@
+void main()
+{
+	gl_FrontColor = gl_Color;
+	gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
+
+	gl_Position[0] = 1; //gl_Vertex[0];
+	gl_Position[1] = 1; //gl_Vertex[1];
+	gl_Position[2] = 1; //gl_Vertex[2];
+
+	vec4 projected = gl_ModelViewProjectionMatrix * gl_Vertex;
+	gl_Position = projected;
+	//gl_Position[3] = 100 + gl_Vertex[3];
+	//gl_Position = gl_Vertex;
+}
-- 
2.43.2