#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <stdio.h>

#define WINDOW_WIDTH 640
#define WINDOW_HEIGHT 480

float verts[] = {
	-0.5f, -0.5f, 0.0f,
	 0.5f, -0.5f, 0.0f,
	 0.0f,  0.5f, 0.0f
};  

void framebuffer_size_callback(GLFWwindow* win, int w, int h) {
	glViewport(0, 0, w, h);
}

void processInput(GLFWwindow *win) {
	int action = glfwGetKey(win, GLFW_KEY_ESCAPE);
	if (action == GLFW_PRESS) {
		glfwSetWindowShouldClose(win, true);
	}
}

void renderCallback(GLFWwindow *win) {
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);

	unsigned int VBO;
	glGenBuffers(1, &VBO);

	glBindBuffer(GL_ARRAY_BUFFER, VBO);
}

int main() {
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* win = glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "Hohmann", NULL, NULL);
	if (win == NULL) {
		printf("Failed to create a window.");
		glfwTerminate();
		return 1;
	}

	glfwMakeContextCurrent(win);

	if ( !gladLoadGLLoader((GLADloadproc)glfwGetProcAddress) ) {
		printf("Failed to init GLAD.");
		return 1;
	}

	glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
	glfwSetFramebufferSizeCallback(win, framebuffer_size_callback);

	while (!glfwWindowShouldClose(win)) {
		// Handle input
		processInput(win);

		// rendering
		renderCallback(win);

		// glfw
		glfwSwapBuffers(win);
		glfwPollEvents();
	}

	glfwTerminate();
	return 0;
}