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

---
 CMakeLists.txt   |  4 +++-
 src/gl/gl.c      | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/gl/gl.test.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 133 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 99964c3..2da7f20 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,7 @@ add_subdirectory(${LIB_ROOT}/cglm)
 
 set(HONEY_LIB_FILES
 	${SRC_ROOT}/logging/logging.c
+	${SRC_ROOT}/gl/glad/glad.c
 	${SRC_ROOT}/gl/gl.c
 	${SRC_ROOT}/gl/window.c
 )
@@ -59,6 +60,7 @@ set(TEST_SOURCES
 	${SRC_ROOT}/test/honey-test.c
 
 	${SRC_ROOT}/logging/logging.test.c
+	${SRC_ROOT}/gl/glad/glad.c
 	${SRC_ROOT}/gl/gl.test.c
 )
 
@@ -66,4 +68,4 @@ add_executable(test EXCLUDE_FROM_ALL ${TEST_SOURCES})
 set_target_properties(test PROPERTIES
 	C_STANDARD 99
 	CMAKE_C_FLAGS "-Wall -Wextra -Werror -Wfatal-errors -Wpedantic")
-target_link_libraries(test lua5.1 honeysuckle)
+target_link_libraries(test lua5.1 honeysuckle dl)
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;
+}
diff --git a/src/gl/gl.test.c b/src/gl/gl.test.c
index 9bacbf9..aa24fd2 100644
--- a/src/gl/gl.test.c
+++ b/src/gl/gl.test.c
@@ -6,13 +6,17 @@
 
 
 int mock_glfwInit_(void);
-int mock_hs_throw_error_(lua_State *L, const char *str);
+int mock_hs_throw_error_(lua_State *L, const char *str, ...);
 void mock_glfwTerminate_();
+void mock_glBufferData_(int, size_t, const void *, int);
 
 #define glfwInit mock_glfwInit_
 #define hs_throw_error mock_hs_throw_error_
 #define glfwTerminate mock_glfwTerminate_
+#undef glBufferData
+#define glBufferData mock_glBufferData_
 #include "gl/gl.c"
+#undef glBufferData
 #undef glfwTerminate
 #undef hs_throw_error
 #undef glfwInit
@@ -31,7 +35,7 @@ int mock_glfwInit_()
 
 
 lily_mock_t *mock_hs_throw_error = NULL;
-int mock_hs_throw_error_(lua_State *L, const char *str)
+int mock_hs_throw_error_(lua_State *L, const char *str, ...)
 {
 	struct lily_mock_arg_t args[] = {
 		{ sizeof(const char *), &str }
@@ -53,6 +57,24 @@ void mock_glfwTerminate_()
 }
 
 
+lily_mock_t *mock_glBufferData = NULL;
+void mock_glBufferData_(int target, size_t size, const void *data, int usage)
+{
+	struct lily_mock_arg_t args[] = {
+		{ sizeof(int), &target },
+		{ sizeof(size_t), &size },
+		{ sizeof(int), &usage }
+	};
+	lily_mock_store_call(mock_glBufferData, args);
+
+	size_t count = size/sizeof(lua_Number);
+	lua_Number *numbers = data;
+	for (int i=0; i<count; i++) {
+		lily_store_value(mock_glBufferData, lua_Number, numbers[i]);
+	}
+}
+
+
 /* ~~~~~~~~ suite ~~~~~~~~ */
 
 void gl_init_succeeds()
@@ -102,13 +124,55 @@ void gl_terminate_works()
 }
 
 
+void gl_buffer_data_works()
+{
+	lily_mock_use(&mock_hs_throw_error);
+	lily_mock_use(&mock_glBufferData);
+
+	lua_State *L = luaL_newstate();
+	lua_pushcfunction(L, gl_buffer_data);
+	lua_pushinteger(L, GL_ARRAY_BUFFER);
+	hs_create_table(L,
+		hs_int_num(1, 22),
+		hs_int_num(2, 33),
+		hs_int_num(3, 44),
+	);
+	lua_pushinteger(L, GL_STATIC_DRAW);
+	int err = hs_call(L, 3, 0);
+	lua_close(L);
+
+	lily_assert_int_equal(err, 0);
+	lily_assert_int_equal(mock_glBufferData->n_calls, 1);
+	int target; size_t size; int usage;
+	struct lily_mock_arg_t args[] = {
+		{ sizeof(int), &target },
+		{ sizeof(size_t), &size },
+		{ sizeof(int), &usage }
+	};
+	lily_mock_get_call(mock_glBufferData, args, 0);
+	lily_assert_int_equal(target, GL_ARRAY_BUFFER);
+	lily_assert_int_equal(size, 3*sizeof(lua_Number));
+	lily_assert_int_equal(usage, GL_STATIC_DRAW);
+
+	lua_Number n;
+	lily_get_value(mock_glBufferData, lua_Number, &n);
+	lily_assert_float_equal(n, 22, 0.1);
+	lily_get_value(mock_glBufferData, lua_Number, &n);
+	lily_assert_float_equal(n, 33, 0.1);
+	lily_get_value(mock_glBufferData, lua_Number, &n);
+	lily_assert_float_equal(n, 44, 0.1);
+}
+
+
 void suite_gl()
 {
 	lily_run_test(gl_init_succeeds);
 	lily_run_test(gl_init_fails);
 	lily_run_test(gl_terminate_works);
+	lily_run_test(gl_buffer_data_works);
 
 	lily_mock_destroy(mock_glfwInit);
 	lily_mock_destroy(mock_hs_throw_error);
 	lily_mock_destroy(mock_glfwTerminate);
+	lily_mock_destroy(mock_glBufferData);
 }
-- 
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