sdl.c

#include "SDL.h"

#include <limits.h>
#include <stdio.h>

#define SCREENWIDTH 640
#define SCREENHEIGHT 480

SDL_Renderer *rend;
SDL_Window *win;
SDL_Surface *screen_surface;

char pixels[SCREENHEIGHT * SCREENWIDTH];
SDL_Colour pal[256];

void
draw()
{
	SDL_RenderClear(rend);

	for (int i = 0; i < sizeof(pixels); i++) {
		pixels[i] = rand() > (INT_MAX / 2) ? 1 : 0;
	}

	SDL_Texture *texture = SDL_CreateTextureFromSurface(rend, screen_surface);
	SDL_RenderCopy(rend, texture, NULL, NULL);
	SDL_DestroyTexture(texture);

	SDL_RenderPresent(rend);
}

int
main()
{
	int flags, rflags;

	memset(pixels, 0, sizeof(pixels));

	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS)) {
		printf("Failed to init SDL: %s\n", SDL_GetError());
		return 1;
	}

	flags = SDL_WINDOW_RESIZABLE;
	win = SDL_CreateWindow("static", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREENWIDTH,
	  SCREENHEIGHT, flags);

	if (!win) {
		printf("Failed to create window: %s\n", SDL_GetError());
		return 1;
	}

	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");

	rflags = SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC;
	rend = SDL_CreateRenderer(win, -1, rflags);
	if (!rend) {
		printf("Failed to create renderer: %s\n", SDL_GetError());
		return 1;
	}

	SDL_GL_SetSwapInterval(1);

	screen_surface = SDL_CreateRGBSurfaceFrom(pixels, SCREENWIDTH, SCREENHEIGHT, 8, SCREENWIDTH, 0,
	  0, 0, 0);
	if (!screen_surface) {
		printf("Failed to create surface: %s\n", SDL_GetError());
		return 1;
	}

	SDL_RenderSetLogicalSize(rend, SCREENWIDTH, SCREENHEIGHT);

	pal[0].a = 0xff;
	pal[0].r = 0;
	pal[0].g = 0;
	pal[0].b = 0;
	for (int i = 1; i < 256; i++) {
		pal[i].a = 0xff;
		pal[i].r = 0xff;
		pal[i].g = 0xff;
		pal[i].b = 0xff;
	}

	SDL_SetPaletteColors(screen_surface->format->palette, pal, 0, 256);

	for (;;) {
		draw();
	}

	return 0;
}