From ecde0c8110da1c1f94cce7f6a1fa9406d04eca69 Mon Sep 17 00:00:00 2001
From: sanine <sanine.not@pm.me>
Date: Fri, 19 Aug 2022 00:39:04 -0500
Subject: add several buffer-related functions

---
 src/gl/gl.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 64 insertions(+), 1 deletion(-)

(limited to 'src/gl/gl.c')

diff --git a/src/gl/gl.c b/src/gl/gl.c
index 8613e70..7b07027 100644
--- a/src/gl/gl.c
+++ b/src/gl/gl.c
@@ -1,18 +1,36 @@
+#include <stdlib.h>
 #include "gl/glad/glad.h"
 #include <GLFW/glfw3.h>
 #include <lua.h>
 #include <honeysuckle.h>
 
+/* needs to be here because glad uses macros to define glBufferData */
+#ifdef HONEY_TEST_H
+#undef glBufferData
+#define glBufferData mock_glBufferData_
+#endif
+
 
 int gl_init(lua_State *L);
 int gl_terminate(lua_State *L);
+int gl_create_buffer(lua_State *L);
+int gl_bind_buffer(lua_State *L);
+int gl_buffer_data(lua_State *L);
 
 
 void setup_gl(lua_State *L, int honey_index)
 {
+	int buffer_binding_targets = hs_create_table(L,
+		hs_str_int("arrayBuffer", GL_ARRAY_BUFFER),
+	);
+
 	hs_create_table(L,
 		hs_str_cfunc("init", gl_init),
-		hs_str_cfunc("terminate", gl_terminate)
+		hs_str_cfunc("terminate", gl_terminate),
+		hs_str_cfunc("createBuffer", gl_create_buffer),
+		hs_str_cfunc("bindBuffer", gl_bind_buffer),
+		hs_str_tbl("bufferTarget", buffer_binding_targets),
+		hs_str_cfunc("bufferData", gl_buffer_data),
 	);
 	lua_setfield(L, honey_index, "gl");
 }
@@ -32,3 +50,48 @@ int gl_terminate(lua_State *L)
 	glfwTerminate();
 	return 0;
 }
+
+
+int gl_create_buffer(lua_State *L)
+{
+	int buf;
+	glGenBuffers(1, &buf);
+	lua_pushinteger(L, buf);
+	return 1;
+}
+
+
+int gl_bind_buffer(lua_State *L)
+{
+	lua_Integer buf, target;
+	hs_parse_args(L, hs_int(buf), hs_int(target));
+	glBindBuffer(buf, target);
+	return 0;
+}
+
+
+int gl_buffer_data(lua_State *L)
+{
+	lua_Integer target, usage;
+	int table;
+	hs_parse_args(L, hs_int(target), hs_tbl(table), hs_int(usage));
+
+	/* build raw buffer */
+	size_t len = lua_objlen(L, table);
+	lua_Number *buf = malloc(len * sizeof(lua_Number));
+	if (buf == NULL)
+		hs_throw_error(L, "failed to allocate intermediary buffer");
+	for (int i=0; i<len; i++) {
+		lua_rawgeti(L, table, i+1);
+		if (!lua_isnumber(L, -1)) {
+			hs_throw_error(L, "all table items must be numbers (failed at index %d)", i);
+		}
+		buf[i] = lua_tonumber(L, -1);
+		lua_pop(L, 1);
+	}
+
+	/* call */
+	glBufferData(target, len*sizeof(lua_Number), buf, usage);
+	free(buf);
+	return 0;
+}
-- 
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