#include GLEW_INCLUDE
#include <SDL.h>

int w=800, h=600;

float vertexData[] = {
	0, 1, 0, 0, 0, 1, 0, 1, 0, 0,
	1, 0, 0, 0, 0, 1, 1, 0, 0, 0,
	0, 0, 0, 0, 0, 1, 0, 0, 0, 0,
};

int indexData[] = {
	0, 1, 2
};

const char* vertSrc =
	"#version 400\n"
	"in vec3 os_Position;\n"
	"void main() {\n"
	"	gl_Position = vec4(os_Position, 1.0);\n"
	"}\n";

const char* fragSrc =
	"#version 400\n"
	"out vec4 Output0;\n"
	"void main() {\n"
	"	Output0 = vec4(1.0);\n"
	"}\n";

int main() {
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
	SDL_Window* win = SDL_CreateWindow("SSCCE", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, w, h, SDL_WINDOW_OPENGL);
	SDL_GLContext ctx = SDL_GL_CreateContext(win);
	glewInit();

	unsigned prog = glCreateProgram();

	unsigned vert = glCreateShader(GL_VERTEX_SHADER);
	int vertSrcLen = strlen(vertSrc);
	glShaderSource(vert, 1, (const GLchar**)&vertSrc, &vertSrcLen);
	glCompileShader(vert);
	glAttachShader(prog, vert);

	unsigned frag = glCreateShader(GL_FRAGMENT_SHADER);
	int fragSrcLen = strlen(fragSrc);
	glShaderSource(frag, 1, (const GLchar**)&fragSrc, &fragSrcLen);
	glCompileShader(frag);
	glAttachShader(prog, frag);

	glBindFragDataLocation(prog, 0, "Output0");
	glLinkProgram(prog);
	glUseProgram(prog);

	glViewport(0, 0, w, h);
	glClearColor(0, 0, 0, 0);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	unsigned vao = 0;
	glGenVertexArrays(1, &vao);
	glBindVertexArray(vao);

	unsigned vbo = 0;
	glGenBuffers(1, &vbo);
	glBindBuffer(GL_ARRAY_BUFFER, vbo);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_STATIC_DRAW);

	int stride = sizeof(float) * (3 + 3 + 4);

	int attrib = glGetAttribLocation(prog, "os_Position");
	printf("attrib = %d\n", attrib);
	glEnableVertexAttribArray(attrib);
	glVertexAttribPointer(attrib, 3, GL_FLOAT, true, stride, (void*)0);

	unsigned ibo = 0;
	glGenBuffers(1, &ibo);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indexData), indexData, GL_STATIC_DRAW);
	glDrawElements(GL_TRIANGLES, sizeof(indexData) / sizeof(indexData[0]), GL_UNSIGNED_INT, 0);

	SDL_GL_SwapWindow(win);
	SDL_Delay(1000);
	return 0;
}