sdl

FORK: Simple Directmedia Layer
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testoffscreen.c (4277B)

      1 /*
      2   Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
      3 
      4   This software is provided 'as-is', without any express or implied
      5   warranty.  In no event will the authors be held liable for any damages
      6   arising from the use of this software.
      7 
      8   Permission is granted to anyone to use this software for any purpose,
      9   including commercial applications, and to alter it and redistribute it
     10   freely.
     11 */
     12 
     13 /* Simple program: picks the offscreen backend and renders each frame to a bmp */
     14 
     15 #include <stdlib.h>
     16 #include <stdio.h>
     17 #include <time.h>
     18 
     19 #ifdef __EMSCRIPTEN__
     20 #include <emscripten/emscripten.h>
     21 #endif
     22 
     23 #include "SDL.h"
     24 #include "SDL_stdinc.h"
     25 #include "SDL_opengl.h"
     26 
     27 static SDL_Renderer *renderer = NULL;
     28 static SDL_Window *window = NULL;
     29 static int done = SDL_FALSE;
     30 static int frame_number = 0;
     31 static int width = 640;
     32 static int height = 480;
     33 static int max_frames = 200;
     34 
     35 void
     36 draw()
     37 {
     38     SDL_Rect Rect;
     39 
     40     SDL_SetRenderDrawColor(renderer, 0x10, 0x9A, 0xCE, 0xFF);
     41     SDL_RenderClear(renderer);
     42 
     43     /* Grow based on the frame just to show a difference per frame of the region */
     44     Rect.x = 0;
     45     Rect.y = 0;
     46     Rect.w = (frame_number * 2) % width;
     47     Rect.h = (frame_number * 2) % height;
     48     SDL_SetRenderDrawColor(renderer, 0xFF, 0x10, 0x21, 0xFF);
     49     SDL_RenderFillRect(renderer, &Rect);
     50 
     51     SDL_RenderPresent(renderer);
     52 }
     53 
     54 void
     55 save_surface_to_bmp()
     56 {
     57     SDL_Surface* surface;
     58     Uint32 r_mask, g_mask, b_mask, a_mask;
     59     Uint32 pixel_format;
     60     char file[128];
     61     int bbp;
     62 
     63     pixel_format = SDL_GetWindowPixelFormat(window);
     64     SDL_PixelFormatEnumToMasks(pixel_format, &bbp, &r_mask, &g_mask, &b_mask, &a_mask);
     65 
     66     surface = SDL_CreateRGBSurface(0, width, height, bbp, r_mask, g_mask, b_mask, a_mask);
     67     SDL_RenderReadPixels(renderer, NULL, pixel_format, (void*)surface->pixels, surface->pitch);
     68 
     69     SDL_snprintf(file, sizeof(file), "SDL_window%d-%8.8d.bmp",
     70         SDL_GetWindowID(window), ++frame_number);
     71 
     72     SDL_SaveBMP(surface, file);
     73     SDL_FreeSurface(surface);
     74 }
     75 
     76 void
     77 loop()
     78 {
     79     SDL_Event event;
     80 
     81     /* Check for events */
     82     while (SDL_PollEvent(&event)) {
     83         switch (event.type) {
     84             case SDL_QUIT:
     85             done = SDL_TRUE;
     86             break;
     87         }
     88     }
     89 
     90     draw();
     91     save_surface_to_bmp();
     92 
     93 #ifdef __EMSCRIPTEN__
     94     if (done) {
     95         emscripten_cancel_main_loop();
     96     }
     97 #endif
     98 }
     99 
    100 int
    101 main(int argc, char *argv[])
    102 {
    103     Uint32 then, now, frames;
    104 
    105     /* Enable standard application logging */
    106     SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
    107 
    108     /* Force the offscreen renderer, if it cannot be created then fail out */
    109     if (SDL_VideoInit("offscreen") < 0) {
    110         SDL_Log("Couldn't initialize the offscreen video driver: %s\n",
    111             SDL_GetError());
    112         return SDL_FALSE;
    113     }
    114 
    115 	/* If OPENGL fails to init it will fallback to using a framebuffer for rendering */
    116     window = SDL_CreateWindow("Offscreen Test",
    117                  SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
    118                  width, height, 0);
    119 
    120     if (!window) {
    121         SDL_Log("Couldn't create window: %s\n",
    122             SDL_GetError());
    123         return SDL_FALSE;
    124     }
    125 
    126     renderer = SDL_CreateRenderer(window, -1, 0);
    127 
    128     if (!renderer) {
    129         SDL_Log("Couldn't create renderer: %s\n",
    130             SDL_GetError());
    131         return SDL_FALSE;
    132     }
    133 
    134     SDL_RenderClear(renderer);
    135 
    136     srand((unsigned int)time(NULL));
    137 
    138     /* Main render loop */
    139     frames = 0;
    140     then = SDL_GetTicks();
    141     done = 0;
    142 
    143     SDL_Log("Rendering %i frames offscreen\n", max_frames);
    144 
    145 #ifdef __EMSCRIPTEN__
    146     emscripten_set_main_loop(loop, 0, 1);
    147 #else
    148     while (!done && frames < max_frames) {
    149         ++frames;
    150         loop();
    151 
    152         /* Print out some timing information, along with remaining frames */
    153         if (frames % (max_frames / 10) == 0) {
    154             now = SDL_GetTicks();
    155             if (now > then) {
    156                 double fps = ((double) frames * 1000) / (now - then);
    157                 SDL_Log("Frames remaining: %i rendering at %2.2f frames per second\n", max_frames - frames, fps);
    158             }
    159         }
    160     }
    161 #endif
    162 
    163     SDL_DestroyRenderer(renderer);
    164     SDL_DestroyWindow(window);
    165     SDL_Quit();
    166 
    167     return 0;
    168 }
    169 
    170 /* vi: set ts=4 sw=4 expandtab: */