hang.c

#include <math.h>
#include <GL/glew.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <SDL2/SDL.h>
#include "utils.h"

int main(int argc, char *argv[])
{
	printf("Hello, World!\n");
	
	//glutInit(&argc, argv);
	//glewInit();
	
	if(SDL_Init(SDL_INIT_VIDEO) < 0)
		goto exit;
	
	SDL_Window *window;
	SDL_Renderer *renderer;
	
	window = SDL_CreateWindow("Hello, World",
							  SDL_WINDOWPOS_CENTERED,
							  SDL_WINDOWPOS_CENTERED,
							  640,
							  480,
							  SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL);
	
	// OpenGL 4.x Core profile
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
	
	renderer = SDL_GL_CreateContext(window);
	
	//GLuint id;
	//glGenBuffers(1, &id);
	
	float hue = 0.0f;
	float step = 1.0f / 10.0f;
	
	Uint64 time_now = SDL_GetPerformanceCounter();
	Uint64 time_last;
	float delta_time;
	
	while(1)
	{
		SDL_Event event;
		
		SDL_PollEvent(&event);
		if(event.type == SDL_QUIT)
		{
			break;
		}
		
		// Calculate delta time
		time_last = time_now;
		time_now = SDL_GetPerformanceCounter();
		
		delta_time = (float) ((time_now - time_last) * 1000 / SDL_GetPerformanceFrequency());
		
		// Calculate bg color
		hue += step * (delta_time / 1000.0f);
		hue = fmodf(hue, 1.0f);
		
		struct rgb_t rgb = hsv_to_rgb((struct hsv_t){hue, 1.0, 1.0});
		
		// Clear
		glClearColor(rgb.r, rgb.g, rgb.b, 1.0);
		glClear(GL_COLOR_BUFFER_BIT);
		
		// ...
		
		SDL_GL_SwapWindow(window);
	}
	
	SDL_DestroyRenderer(renderer);
	SDL_DestroyWindow(window);
	
	exit:
	SDL_Quit();
	return 0;
}