texture.c

#include <stdio.h>
#include <SDL2/SDL.h>

const int WIN_WIDTH = 640;
const int WIN_HEIGHT = 480;

int main(int argc, char **argv){
	if (SDL_Init(SDL_INIT_EVERYTHING) != 0){
		printf("SDL_Init failed: %s\n", SDL_GetError());
		return 1;
	}
	SDL_Window *win = SDL_CreateWindow("Rendering to a texture!", SDL_WINDOWPOS_CENTERED,
		SDL_WINDOWPOS_CENTERED, WIN_WIDTH, WIN_HEIGHT, 0);
	SDL_Renderer *renderer = SDL_CreateRenderer(win, -1,
		SDL_RENDERER_ACCELERATED | SDL_RENDERER_TARGETTEXTURE);

	//Make a target texture to render too
	SDL_Texture *texTarget = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
		SDL_TEXTUREACCESS_TARGET, WIN_WIDTH, WIN_HEIGHT);
	
	//Now render to the texture
	
	for(int l = 0; l < 6000; l++){
		SDL_SetRenderTarget(renderer, texTarget);
		
		SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
		SDL_RenderClear(renderer);
	
		SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
		
		for(int i = 0; i < 4; i++)
			for(int j = 0; j < 600; j++)
				SDL_RenderDrawLine(renderer, i*100, i*100 + j, i*100 + 100, i*100 + 100+ j);
		
		//Detach the texture
		SDL_SetRenderTarget(renderer, NULL);

		//Now render the texture target to our screen, but upside down
		//~ SDL_RenderClear(renderer);
		SDL_RenderCopy(renderer, texTarget, NULL, NULL);
		//~ SDL_RenderCopyEx(renderer, texTarget, NULL, NULL, 0, NULL, SDL_FLIP_VERTICAL);
		SDL_RenderPresent(renderer);
	
	}
	
	SDL_DestroyTexture(texTarget);
	SDL_DestroyRenderer(renderer);
	SDL_DestroyWindow(win);
	SDL_Quit();
	return 0;
}