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/*******************************************************************************
 * The MIT License
 * 
 * Copyright (c) <2009> Stefan 'psYchotic' Zwanenburg
 *                      stefanhetzwaantje@gmail.com
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * Compile with:
 *      gcc display_data.c `sdl-config --cflags --libs`
 ******************************************************************************/

#include "SDL.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Size of each rectangle
#define RECTSIZE 2

short paused = 0;

// Handles events.
int event_filter(const SDL_Event *event) {
    // User defined event to push when
    // we unpause
    SDL_Event pause_event;
    pause_event.type = SDL_USEREVENT;
    pause_event.user.code = 0;
    pause_event.user.data1 = NULL;
    pause_event.user.data2 = NULL;

    // What kind of event is being processed?
    switch (event->type) {
        // A key has been pressed
        case SDL_KEYDOWN:
            switch (event->key.keysym.sym) {
                case SDLK_q:
                case SDLK_ESCAPE:
                    printf("Quitting because of a keypress\n");
                    exit(EXIT_SUCCESS);
                    break;
                case SDLK_SPACE:
                    // Pause and send an event.
                    paused ^= 1;
                    SDL_PushEvent(&pause_event);
                    break;
                default:
                    break;
            }
            break;
        default:
            break;
    }

    return 0;
}

int main(int argc, char **argv) {
    // Initialize SDL.
    if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE | SDL_INIT_EVENTTHREAD)) {
        printf("Couldn't initialize SDL: %s.\nQuitting.\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }

    // Make sure SDL_Quit is called upon exiting this program.
    atexit(SDL_Quit);

    SDL_Surface *screen;
    int video_mask = SDL_HWSURFACE | SDL_DOUBLEBUF | SDL_ANYFORMAT;
    int i;
    // Loop for processing the commandline arguments.
    for (i = 1; i < argc; i++) {
        if (!strcmp("-fs", argv[i]) || !strcmp("--fullscreen", argv[i])) {
            video_mask |= SDL_FULLSCREEN;
        } else if (!strcmp("-h", argv[i]) || !strcmp("--help", argv[i])) {
            printf("Usage: %s [-h | --help] [-fs | --fullscreen]\n", argv[0]);
            exit(EXIT_SUCCESS);
        }
    }

    // Sets up a surface to draw on.
    if ((video_mask & SDL_FULLSCREEN) == SDL_FULLSCREEN) {
        screen = SDL_SetVideoMode(0, 0, 32, video_mask);
    } else {
        screen = SDL_SetVideoMode(640, 480, 32, video_mask);
    }

    if (!screen) {
        printf("Couldn't create a surface for SDL: %s.\nQuitting\n", SDL_GetError());
        exit(EXIT_FAILURE);
    }

    // Don't show a mouse cursor
    SDL_ShowCursor(SDL_DISABLE);
    // Set our event filter.
    SDL_SetEventFilter(event_filter);
    SDL_Rect rect;
    SDL_Event event;
    // Standard input.
    SDL_RWops *input = SDL_RWFromFP(stdin, 0);
    if (!input) {
        printf("Failed to open stdin. Quitting.\n");
        exit(EXIT_FAILURE);
    }
    short filled = 0;
    unsigned char buf[3];

    while (1) {
        // If paused, wait for an event.
        while (paused && SDL_WaitEvent(&event)) {}

        // Read 3 bytes (RGB) from standard input
        if (SDL_RWread(input, buf, 1, 3) != 3) {
            printf("Quitting because there is no more input\n");
            exit(EXIT_SUCCESS);
            continue;
        }

        // If a full horizontal line has been drawn,
        // shift the whole surface up and clear the bottom
        // line.
        if (filled >= screen->w) {
            filled = 0;
            rect.x = 0;         rect.y = RECTSIZE;
            rect.w = screen->w; rect.h = screen->h - RECTSIZE;
            SDL_BlitSurface(screen, &rect, screen, NULL);
            rect.y = screen->h - RECTSIZE;
            rect.h = RECTSIZE;
            SDL_FillRect(screen, &rect, SDL_MapRGB(screen->format, 0x00, 0x00, 0x00));
            SDL_Flip(screen);
        }

        // Draw a single rectangle
        rect.x = filled;    rect.y = screen->h - RECTSIZE;
        rect.w = RECTSIZE;   rect.h = RECTSIZE;
        SDL_FillRect(screen, &rect, SDL_MapRGB(screen->format, buf[0], buf[1], buf[2]));
        filled += RECTSIZE;
    }

    return 0;
}