Fun with shaders

git-svn-id: svn://cook.msm.cam.ac.uk:745/diff-tomo/dtr@235 bf6ca9ba-c028-0410-8290-897cf20841d1

1 files changed, 79 insertions, 1 deletions

diff --git a/src/glbits.c b/src/glbits.c
index 194a919..9a7fca5 100644
--- a/src/glbits.c
+++ b/src/glbits.c
@@ -28,7 +28,53 @@
 #include "reflections.h"
 #include "image.h"
 
-#define BLOB_BITS 5
+/* Utility function to load and compile a shader, checking the info log */
+static GLhandleARB glbits_load_shader(const char *filename, GLenum type) {
+
+	GLhandleARB shader;
+	char text[4096];
+	size_t len;
+	FILE *fh;
+	int l;
+	
+	fh = fopen(filename, "r");
+	len = fread(text, 1, 4095, fh);
+	fclose(fh);
+	text[len] = '\0';
+	const GLcharARB *source = text;
+	shader = glCreateShaderObjectARB(type);
+	glShaderSourceARB(shader, 1, &source, NULL);
+	glCompileShaderARB(shader);
+	glGetInfoLogARB(shader, 4095, &l, text);
+	if ( l > 0 ) {
+		printf("%s\n", text); fflush(stdout);
+	}
+	
+	return shader;
+	
+}
+
+static void glbits_load_shaders(DisplayWindow *dw) {
+	
+	dw->gl_vshader_lightpp = glbits_load_shader(DATADIR"/dtr/light-pp.vert", GL_VERTEX_SHADER_ARB);
+	dw->gl_fshader_lightpp = glbits_load_shader(DATADIR"/dtr/light-pp.frag", GL_FRAGMENT_SHADER_ARB);
+		
+	dw->gl_program_lightpp = glCreateProgramObjectARB();
+	glAttachObjectARB(dw->gl_program_lightpp, dw->gl_vshader_lightpp);
+	glAttachObjectARB(dw->gl_program_lightpp, dw->gl_fshader_lightpp);
+	glLinkProgramARB(dw->gl_program_lightpp);
+	
+}
+
+static void glbits_delete_shaders(DisplayWindow *dw) {
+
+	glDetachObjectARB(dw->gl_program_lightpp, dw->gl_fshader_lightpp);
+	glDeleteObjectARB(dw->gl_fshader_lightpp);
+	glDeleteObjectARB(dw->gl_program_lightpp);
+
+}
+
+#define BLOB_BITS 7
 #define VERTICES_IN_A_BLOB 4*BLOB_BITS*BLOB_BITS*2
 #define ADD_VERTEX 						\
 	vertices[3*i + 0] = reflection->x/1e9 + size*xv;	\
@@ -704,6 +750,7 @@ gint glbits_expose(GtkWidget *widget, GdkEventExpose *event, DisplayWindow *dw)
 			glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, gold);
 			glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, gold_spec);
 			glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, 70.0);
+			glUseProgramObjectARB(dw->gl_program_lightpp);
 			if ( dw->gl_use_buffers ) {
 				glBindBufferARB(GL_ARRAY_BUFFER, dw->gl_gen_vertex_buffer);
 				glVertexPointer(3, GL_FLOAT, 0, NULL);
@@ -716,6 +763,7 @@ gint glbits_expose(GtkWidget *widget, GdkEventExpose *event, DisplayWindow *dw)
 				glNormalPointer(GL_FLOAT, 0, dw->gl_gen_normal_array);
 				glDrawArrays(GL_QUADS, 0, dw->gl_gen_num_vertices);
 			}
+			glUseProgramObjectARB(0);
 			glDisableClientState(GL_NORMAL_ARRAY);
 			glPopClientAttrib();
 		}
@@ -812,3 +860,33 @@ void glbits_free_resources(DisplayWindow *dw) {
 	
 }
 
+void glbits_final_free_resources(DisplayWindow *dw) {
+	glbits_free_resources(dw);
+	glbits_delete_shaders(dw);
+}
+
+static void glbits_first_prepare(DisplayWindow *dw) {
+	glbits_prepare(dw);
+	glbits_load_shaders(dw);
+}
+
+gint glbits_realise(GtkWidget *widget, DisplayWindow *dw) {
+
+	GdkGLContext *glcontext = gtk_widget_get_gl_context(widget);
+	GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(widget);
+	GLfloat w = widget->allocation.width;
+	GLfloat h = widget->allocation.height;
+	
+	if ( !gdk_gl_drawable_gl_begin(gldrawable, glcontext) ) {
+		return 0;
+	}
+	
+	glbits_set_ortho(dw, w, h);
+	glbits_first_prepare(dw);
+	
+	gdk_gl_drawable_gl_end(gldrawable);
+
+	return 0;
+
+}
+