#ifdef _WIN32
typedef __int64 GLintptr;
#else
typedef intptr_t GLintptr;
#endif
typedef void GLvoid;
typedef unsigned char GLboolean;
typedef unsigned char GLubyte;
typedef char GLchar;

typedef int GLint;
typedef int GLsizei;

typedef unsigned int GLenum;
typedef unsigned int GLuint;
typedef unsigned int GLbitfield;

typedef float GLfloat;
typedef double GLdouble;

typedef unsigned long long GLsizeiptr;

#define GL_NO_ERROR 0
#define GL_INFO_LOG_LENGTH 0x8b84
#define GL_ZERO 0x0000
#define GL_ONE 0x0001
#define GL_ALPHA 0x1906
#define GL_BLEND 0x0be2
#define GL_CLAMP_TO_EDGE 0x812f
#define GL_COLOR_BUFFER_BIT 0x4000
#define GL_COMPILE_STATUS 0x8b81
#define GL_DEPTH_TEST 0x0b71
#define GL_FRAMEBUFFER_SRGB 0x8db9
#define GL_FRAGMENT_SHADER 0x8b30
#define GL_LINK_STATUS 0x8b82
#define GL_MODELVIEW 0x1700
#define GL_NEAREST 0x2600
#define GL_ONE_MINUS_SRC_ALPHA 0x0303
#define GL_PROJECTION 0x1701
#define GL_QUADS 0x0007
#define GL_RGBA 0x1908
#define GL_RGBA8 0x8058
#define GL_SCISSOR_TEST 0x0c11
#define GL_SRGB8_ALPHA8 0x8c43
#define GL_SRC_ALPHA 0x0302
#define GL_TEXTURE0 0x84c0
#define GL_TEXTURE_2D 0x0de1
#define GL_TEXTURE_COORD_ARRAY 0x8078
#define GL_TEXTURE_MAG_FILTER 0x2800
#define GL_TEXTURE_MIN_FILTER 0x2801
#define GL_TEXTURE_WRAP_S 0x2802
#define GL_TEXTURE_WRAP_T 0x2803
#define GL_UNSIGNED_BYTE 0x1401
#define GL_UNSIGNED_INT_8_8_8_8 0x8035
#define GL_VERTEX_SHADER 0x8b31
#define GL_ARRAY_BUFFER 0x8892
#define GL_ELEMENT_ARRAY_BUFFER 0x8893
#define GL_STATIC_DRAW 0x88e4
#define GL_FLOAT 0x1406
#define GL_FALSE 0
#define GL_TRUE 1
#define GL_LINEAR 0x2601
#define GL_FUNC_ADD 0x8006
#define GL_CULL_FACE 0x0b44
#define GL_STREAM_DRAW 0x88e0
#define GL_WRITE_ONLY 0x88b9
#define GL_TRIANGLES 0x0004
#define GL_UNSIGNED_INT 0x1405
#define GL_UNSIGNED_SHORT 0x1403
#define GL_MULTISAMPLE 0x809d
#define GL_DYNAMIC_DRAW 0x88e8
#define GL_RED 0x1903
#define GL_FRAMEBUFFER_WIDTH 0x9310
#define GL_FRAMEBUFFER_HEIGHT 0x9311
#define GL_VIEWPORT 0x0ba2
#define GL_PIXEL_UNPACK_BUFFER 0x88ec
#define GL_PIXEL_UNPACK_BUFFER_BINDING 0x88ef
#define GL_VERTEX_ARRAY_BINDING 0x85b5
#define GL_ARRAY_BUFFER_BINDING 0x8894
#define GL_ELEMENT_ARRAY_BUFFER_BINDING 0x8895
#define GL_CURRENT_PROGRAM 0x8b8d
#define GL_TEXTURE_BINDING_2D 0x8069
#define GL_LINEAR_MIPMAP_LINEAR 0x2703
#define GL_SRGB_ALPHA 0x8c43
#define GL_UNPACK_ROW_LENGTH 0x0cf2
#define GL_UNPACK_SKIP_PIXELS 0x0cf4
#define GL_UNPACK_SKIP_ROWS 0x0cf3
#define GL_TRIANGLE_STRIP 0x0005
#define GL_VERTEX_ATTRIB_ARRAY_ENABLED 0x8646

#define DECLARE_GL_FUNCTION(Name, ReturnType, ...) typedef ReturnType (*type_##Name)(__VA_ARGS__);
#define DECLARE_GLOBAL_FUNCTION(Name, ...) type_##Name Name;

#define GL_FUNCTIONS(X) \
	X(glActiveTexture, void, GLenum texture) \
	X(glAttachShader, void, GLuint program, GLuint shader) \
	X(glBindBuffer, void, GLenum target, GLuint buffer) \
	X(glBindTexture, void, GLenum target, GLuint texture) \
	X(glBufferData, void, GLenum target, GLsizeiptr size, const GLvoid *data, GLenum usage) \
	X(glClear, void, GLbitfield mask) \
	X(glClearColor, void, GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha) \
	X(glCompileShader, void, GLuint shader) \
	X(glCreateProgram, GLuint) \
	X(glCreateShader, GLuint, GLenum type) \
	X(glDeleteShader, void, GLuint shader) \
	X(glDrawElements, void, GLenum mode, GLsizei count, GLenum type, const GLvoid *indices) \
	X(glEnableVertexAttribArray, void, GLuint index) \
	X(glGenBuffers, void, GLsizei n, GLuint *buffers) \
	X(glGenTextures, void, GLsizei n, GLuint *textures) \
	X(glGetShaderInfoLog, void, GLuint shader, GLsizei maxLength, GLsizei *length, GLchar *infoLog) \
	X(glGetShaderiv, void, GLuint shader, GLenum pname, GLint *params) \
	X(glGetUniformLocation, GLint, GLuint program, const GLchar *name) \
	X(glLinkProgram, void, GLuint program) \
	X(glShaderSource, void, GLuint shader, GLsizei count, const GLchar *const *string, const GLint *length) \
	X(glTexImage2D, void, GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const GLvoid *pixels) \
	X(glTexParameteri, void, GLenum target, GLenum pname, GLint param) \
	X(glTexSubImage2D, void, GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const GLvoid *pixels) \
	X(glUniform1f, void, GLint location, GLfloat v0) \
	X(glUniform1i, void, GLint location, GLint v0) \
	X(glUniform2f, void, GLint location, GLfloat v0, GLfloat v1) \
	X(glUniform4f, void, GLint location, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3) \
	X(glUseProgram, void, GLuint program) \
	X(glVertexAttribPointer, void, GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *pointer) \
	X(glViewport, void, GLint x, GLint y, GLsizei width, GLsizei height) \
	X(glDeleteProgram, void, GLuint program) \
	X(glDeleteBuffers, void, GLsizei n, const GLuint *buffers) \
	X(glDeleteTextures, void, GLsizei n, const GLuint *textures) \
	X(glEnable, void, GLenum cap) \
	X(glGenerateMipmap, void, GLenum target) \
	X(glGetProgramiv, void, GLuint program, GLenum pname, GLint *params) \
	X(glGetAttribLocation, GLint, GLuint program, const GLchar *name) \
	X(glDetachShader, void, GLuint program, GLuint shader) \
	X(glUniformMatrix4fv, void, GLint location, GLsizei count, GLboolean transpose, const GLfloat *value) \
	X(glMapBuffer, void*, GLenum target, GLenum access) \
	X(glUnmapBuffer, GLboolean, GLenum target) \
	X(glBlendEquation, void, GLenum mode) \
	X(glBlendFunc, void, GLenum sfactor, GLenum dfactor) \
	X(glDisable, void, GLenum cap) \
	X(glScissor, void, GLint x, GLint y, GLsizei width, GLsizei height) \
	X(glTexCoord2f, void, GLfloat s, GLfloat t) \
	X(glVertex2f, void, GLfloat x, GLfloat y) \
	X(glGetError, GLenum) \
	X(glGetProgramInfoLog, void, GLuint program, GLsizei maxLength, GLsizei *length, GLchar *infoLog) \
	X(glGenVertexArrays, void, GLsizei n, GLuint *arrays) \
	X(glBindVertexArray, void, GLuint array) \
	X(glDeleteVertexArrays, void, GLsizei n, const GLuint *arrays) \
	X(glDrawArrays, void, GLenum mode, GLint first, GLsizei count) \
	X(glBufferSubData, void, GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid *data) \
	X(glDisableVertexAttribArray, void, GLuint index) \
	X(glGetIntegerv, void, GLenum pname, GLint *data) \
	X(glBindAttribLocation, void, GLuint program, GLuint index, const GLchar *name) \
	X(glGetUniformfv, void, GLuint program, GLint location, GLfloat *params) \
	X(glPixelStorei, void, GLenum pname, GLint param) \
	X(glGetVertexAttribiv, void, GLuint index, GLenum pname, GLint *params) \
	X(glFinish, void)

GL_FUNCTIONS(DECLARE_GL_FUNCTION)
GL_FUNCTIONS(DECLARE_GLOBAL_FUNCTION)


#if defined(_WIN32)
static void *get_any_gl_address(const char *name) {
	void *p = (void *)wglGetProcAddress(name);
	if(!p) {
		HMODULE module = LoadLibraryA("opengl32.dll");
		if(module) {
			p = (void *)GetProcAddress(module, name);
		}
	}
	return p;
}

#define GetOpenGLFunction(Name, ...) \
	*(void **)&Name = (void *)get_any_gl_address(#Name); \
	if(!Name) { \
		DEBUG_PRINT("Failed to load OpenGL function: %s\n", #Name); \
		exit(EXIT_FAILURE); \
	}

#elif defined(__linux__)
#include <dlfcn.h>
static void *glXGetProcAddress(const GLubyte *procName) {
	static void *(*glxGetProcAddress)(const GLubyte *);
	if(!glxGetProcAddress) {
		void *libGL = dlopen("libGL.so.1", RTLD_LAZY | RTLD_GLOBAL);
		if(!libGL) {
			DEBUG_PRINT("Error: Unable to load libGL.so.1\n");
			exit(EXIT_FAILURE);
		}
		glxGetProcAddress = dlsym(libGL, "glXGetProcAddress");
		if(!glxGetProcAddress) {
			DEBUG_PRINT("Error: Unable to find glXGetProcAddress\n");
			exit(EXIT_FAILURE);
		}
	}
	return glxGetProcAddress(procName);
}

#define GetOpenGLFunction(Name, ...) \
	*(void **)&Name = (void *)glXGetProcAddress((const GLubyte *)#Name); \
	if(!Name) { \
		DEBUG_PRINT("Failed to load OpenGL function: %s\n", #Name); \
		exit(EXIT_FAILURE); \
	}
#endif

__attribute__((cold, noinline, section(".init_section")))
static void gl_loader() {
	GL_FUNCTIONS(GetOpenGLFunction);
};