From 7c1edef3ac501d40e3de495b9434df71f535e9bc Mon Sep 17 00:00:00 2001
From: Tomasz Kramkowski <tk@the-tk.com>
Date: Fri, 19 Oct 2018 23:22:07 +0300
Subject: Allow multiple shaders while reducing duplication

This change also stops using bie as eventually it will be replaced with
a more sophisticated asset handling system which will also allow custom
shaders.
---
 glprog.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 98 insertions(+), 15 deletions(-)

(limited to 'glprog.c')

diff --git a/glprog.c b/glprog.c
index 5019af2..2996889 100644
--- a/glprog.c
+++ b/glprog.c
@@ -3,23 +3,87 @@
  * SPDX-License-Identifier: MIT
  */
 #include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "eprintf.h"
 #include "gl.h"
 #include "glprog.h"
+#include "nelem.h"
 
 enum {
 	LOGSIZE = 1024,
 };
 
-static GLuint load_shader(const struct shdrdat *shdr)
+struct glprog_progs prog;
+
+static const struct {
+	GLuint type;
+	const char *name;
+	bool reqd;
+	const char *pre;
+} langs[] = {
+	{ GL_VERTEX_SHADER, "vert", true,
+#define SH_IN(type, name) "in " #type " " #name ";\n"
+#include "shaders/data.h"
+	},
+	{ GL_TESS_CONTROL_SHADER, "tesc", false, "" },
+	{ GL_TESS_EVALUATION_SHADER, "tese", false, "" },
+	{ GL_GEOMETRY_SHADER, "geom", false, "" },
+	{ GL_FRAGMENT_SHADER, "frag", true,
+#define SH_TEX(type, name) "uniform sampler" #type " " #name ";\n"
+#define SH_OUT(type, name) "out " #type " " #name ";\n"
+#include "shaders/data.h"
+	},
+};
+
+static bool readfile(char **data, size_t *size, const char *name)
+{
+	FILE *f;
+	size_t len = 0;
+
+	assert(data != NULL);
+	assert(size != NULL);
+	assert(name != NULL);
+
+	f = fopen(name, "rb");
+	if (f == NULL) return false;
+	if (*size < 1024) {
+		*size = 1024;
+		*data = erealloc(*data, *size);
+	}
+
+	while (true) {
+		size_t read = fread(*data + len, 1, *size - len, f);
+		len += read;
+		if (*size - len > 0) break;
+		*size *= 2;
+		*data = erealloc(*data, *size);
+	}
+
+	*size = len;
+	*data = erealloc(*data, *size);
+
+	return true;
+}
+
+static GLuint compile(const char *src, size_t len, const char *pre, GLuint type)
 {
 	GLuint id;
 	GLint success;
 	char log[LOGSIZE];
+	static const char *common_pre =
+#define SH_VER(v) "#version " v "\n"
+#define SH_UNI(type, name) "uniform " #type " " #name ";\n"
+#include "shaders/data.h"
+		;
+	const char *srcs[] = { common_pre, pre, src };
+	GLint lens[] = { -1, -1, len };
 
-	id = gl_shdr_create(shdr->type);
-	gl_shdr_source(id, 1, &shdr->src, &shdr->len);
+	id = gl_shdr_create(type);
+	gl_shdr_source(id, NELEM(srcs), srcs, lens);
 	gl_shdr_compile(id);
 	gl_shdr_param(id, GL_COMPILE_STATUS, &success);
 
@@ -31,7 +95,7 @@ static GLuint load_shader(const struct shdrdat *shdr)
 	return id;
 }
 
-void detach_shaders(GLuint prog)
+static void detach_shaders(GLuint prog)
 {
 	GLsizei count;
 	GLuint shdr;
@@ -40,33 +104,52 @@ void detach_shaders(GLuint prog)
 		gl_prog_detachshdr(prog, shdr);
 }
 
-GLuint glprog_load(const struct shdrdat *shdrs, const struct unidat *unis)
+static void load_shader(struct shader *s, const char *path)
 {
 	GLuint prog;
 	GLint success;
-	char log[LOGSIZE];
+	char log[LOGSIZE], *full, *src = NULL;
+	size_t srclen = 0, fullsz;
+
+	assert(s != NULL);
+	assert(path != NULL);
 
-	assert(shdrs != NULL);
+	fullsz = strlen(path) + strlen("/xxxx.glsl") + 1;
+	assert(fullsz > strlen(path));
+	full = emalloc(fullsz);
 
 	prog = gl_prog_create();
-	for (const struct shdrdat *s = shdrs; s->type != 0; s++) {
-		GLuint shdr = load_shader(s);
+	for (size_t i = 0; i < NELEM(langs); i++) {
+		GLuint shdr;
+
+		snprintf(full, fullsz, "%s/%s.glsl", path, langs[i].name);
+		if (!readfile(&src, &srclen, full)) {
+			if (!langs[i].reqd) continue;
+			eprintf("Could not load shader file %s:\n", full);
+		}
+		shdr = compile(src, srclen, langs[i].pre, langs[i].type);
 		gl_prog_attachshdr(prog, shdr);
 		gl_shdr_del(shdr);
 	}
+	free(src);
+	free(full);
 	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);
+		eprintf("Failed to link program\n%s", log);
 	}
 
 	detach_shaders(prog);
 
-	if (unis == NULL) return prog;
-
-	for (const struct unidat *u = unis; u->name != NULL; u++)
-		*u->loc = gl_uni_loc(prog, u->name);
+#define SH_UNI(_, name) s->uni.name = gl_uni_loc(prog, #name);
+#define SH_TEX(_, name) s->tex.name = gl_uni_loc(prog, #name);
+#include "shaders/data.h"
+	s->prog = prog;
+}
 
-	return prog;
+void glprog_init(void)
+{
+#define SH_PROG(name) load_shader(&prog.name, "shaders/" #name);
+#include "shaders/data.h"
 }
-- 
cgit v1.2.3-54-g00ecf