glprog: Wrap OpenGL program object loading

glprog provides a simple interface to loadign OpenGL program objects
and getting their uniform locations.

1 files changed, 72 insertions, 0 deletions

diff --git a/glprog.c b/glprog.c
new file mode 100644
index 0000000..84f2bab
--- /dev/null
+++ b/glprog.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2018 Tomasz Kramkowski <tk@the-tk.com>
+ * SPDX-License-Identifier: MIT
+ */
+#include <assert.h>
+
+#include "eprintf.h"
+#include "glprog.h"
+#include "loadgl.h"
+
+enum {
+	LOGSIZE = 1024,
+};
+
+static GLuint load_shader(const struct shdrdat *shdr)
+{
+	GLuint id;
+	GLint success;
+	char log[LOGSIZE];
+
+	id = gl_shdr_create(shdr->type);
+	gl_shdr_source(id, 1, &shdr->src, &shdr->len);
+	gl_shdr_compile(id);
+	gl_shdr_param(id, GL_COMPILE_STATUS, &success);
+
+	if (!success) {
+		gl_shdr_infolog(id, sizeof log, NULL, log);
+		eprintf("Failed to compile shader:\n%s", log);
+	}
+
+	return id;
+}
+
+void detach_shaders(GLuint prog)
+{
+	GLsizei count;
+	GLuint shdr;
+
+	while (gl_prog_getshdrs(prog, 1, &count, &shdr), count)
+		gl_prog_detachshdr(prog, shdr);
+}
+
+GLuint glprog_load(int nshdrs, const struct shdrdat *shdrs, int nunis, const struct unidat *unis)
+{
+	GLuint prog;
+	GLint success;
+	char log[LOGSIZE];
+
+	assert(nshdrs > 0);
+	assert(shdrs != NULL);
+	assert(nunis <= 0 || unis != NULL);
+
+	prog = gl_prog_create();
+	for (int i = 0; i < nshdrs; i++) {
+		GLuint shdr = load_shader(&shdrs[i]);
+		gl_prog_attachshdr(prog, shdr);
+		gl_shdr_del(shdr);
+	}
+	gl_prog_link(prog);
+	gl_prog_param(prog, GL_LINK_STATUS, &success);
+	if (!success) {
+		gl_prog_infolog(prog, sizeof log, NULL, log);
+		eprintf("Failed to link program:\n%s", log);
+	}
+
+	detach_shaders(prog);
+
+	for (int i = 0; i < nunis; i++)
+		*unis[i].loc = gl_uni_loc(prog, unis[i].name);
+
+	return prog;
+}