Demoscene Editor

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SDL2 window will appear above. Edit the mathematical function (highlighted) to create your own effects!

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Edit the highlighted mathematical function below:
Change the formula to create different visual effects

#include <SDL.h>
#include <cmath>
#include <chrono>

uint32_t colors[16] = {0xFF000000,0xFF800000,0xFF008000,0xFF808000,0xFF000080,0xFF800080,0xFF008080,0xFFC0C0C0,0xFF808080,0xFFFF0000,0xFF00FF00,0xFFFFFF00,0xFF0000FF,0xFFFF00FF,0xFF00FFFF,0xFFFFFFFF};

int main(int argc, char** argv) {
    int W=80, H=24, scale=8;
    if(argc>=5){W=atoi(argv[1])/scale; H=atoi(argv[2])/scale;}
    
    SDL_Init(SDL_INIT_VIDEO);
    SDL_Window* window = SDL_CreateWindow("", atoi(argv[3]), atoi(argv[4]), W*scale, H*scale, SDL_WINDOW_BORDERLESS);
    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
    SDL_Texture* texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_STREAMING, W, H);
    
    uint32_t* pixels = new uint32_t[W*H];
    auto start = std::chrono::steady_clock::now();
    bool running = true;
    SDL_Event ev;
    
    while(running) {
        while(SDL_PollEvent(&ev)) if(ev.type==SDL_QUIT||(ev.type==SDL_KEYDOWN&&ev.key.keysym.sym==SDLK_ESCAPE)) running=false;
        double t = std::chrono::duration<double>(std::chrono::steady_clock::now()-start).count();
        
        for(int r=0;r<H;r++) for(int c=0;c<W;c++) {
            /* EDITABLE_SECTION_START */
            int col = (sin(c*0.2+t)+1)*7.5;
            /* EDITABLE_SECTION_END */
            pixels[r*W+c] = colors[col>15?15:col<0?0:col];
        }
        
        SDL_UpdateTexture(texture, NULL, pixels, W*sizeof(uint32_t));
        SDL_RenderClear(renderer);
        SDL_RenderCopy(renderer, texture, NULL, NULL);
        SDL_RenderPresent(renderer);
        SDL_Delay(16);
    }
    
    delete[] pixels;
    SDL_DestroyTexture(texture);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}

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