kc3-lang/SDL/test/testoffscreen.c

Branch : - branch - v2.28 - tag -

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• Author : Sam Lantinga
  Date : 2021-01-02 10:25:38
  Hash : 9130f7c3
  Message : Updated copyright for 2021

• test/testoffscreen.c

• /*
    Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely.
  */
  
  /* Simple program: picks the offscreen backend and renders each frame to a bmp */
  
  #include <stdlib.h>
  #include <stdio.h>
  #include <time.h>
  
  #ifdef __EMSCRIPTEN__
  #include <emscripten/emscripten.h>
  #endif
  
  #include "SDL.h"
  #include "SDL_stdinc.h"
  #include "SDL_opengl.h"
  
  static SDL_Renderer *renderer = NULL;
  static SDL_Window *window = NULL;
  static int done = SDL_FALSE;
  static int frame_number = 0;
  static int width = 640;
  static int height = 480;
  static int max_frames = 200;
  
  void
  draw()
  {
      SDL_Rect Rect;
  
      SDL_SetRenderDrawColor(renderer, 0x10, 0x9A, 0xCE, 0xFF);
      SDL_RenderClear(renderer);
  
      /* Grow based on the frame just to show a difference per frame of the region */
      Rect.x = 0;
      Rect.y = 0;
      Rect.w = (frame_number * 2) % width;
      Rect.h = (frame_number * 2) % height;
      SDL_SetRenderDrawColor(renderer, 0xFF, 0x10, 0x21, 0xFF);
      SDL_RenderFillRect(renderer, &Rect);
  
      SDL_RenderPresent(renderer);
  }
  
  void
  save_surface_to_bmp()
  {
      SDL_Surface* surface;
      Uint32 r_mask, g_mask, b_mask, a_mask;
      Uint32 pixel_format;
      char file[128];
      int bbp;
  
      pixel_format = SDL_GetWindowPixelFormat(window);
      SDL_PixelFormatEnumToMasks(pixel_format, &bbp, &r_mask, &g_mask, &b_mask, &a_mask);
  
      surface = SDL_CreateRGBSurface(0, width, height, bbp, r_mask, g_mask, b_mask, a_mask);
      SDL_RenderReadPixels(renderer, NULL, pixel_format, (void*)surface->pixels, surface->pitch);
  
      SDL_snprintf(file, sizeof(file), "SDL_window%d-%8.8d.bmp",
          SDL_GetWindowID(window), ++frame_number);
  
      SDL_SaveBMP(surface, file);
      SDL_FreeSurface(surface);
  }
  
  void
  loop()
  {
      SDL_Event event;
  
      /* Check for events */
      while (SDL_PollEvent(&event)) {
          switch (event.type) {
              case SDL_QUIT:
              done = SDL_TRUE;
              break;
          }
      }
  
      draw();
      save_surface_to_bmp();
  
  #ifdef __EMSCRIPTEN__
      if (done) {
          emscripten_cancel_main_loop();
      }
  #endif
  }
  
  int
  main(int argc, char *argv[])
  {
      Uint32 then, now, frames;
  
      /* Enable standard application logging */
      SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
  
      /* Force the offscreen renderer, if it cannot be created then fail out */
      if (SDL_VideoInit("offscreen") < 0) {
          SDL_Log("Couldn't initialize the offscreen video driver: %s\n",
              SDL_GetError());
          return SDL_FALSE;
      }
  
  	/* If OPENGL fails to init it will fallback to using a framebuffer for rendering */
      window = SDL_CreateWindow("Offscreen Test",
                   SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
                   width, height, 0);
  
      if (!window) {
          SDL_Log("Couldn't create window: %s\n",
              SDL_GetError());
          return SDL_FALSE;
      }
  
      renderer = SDL_CreateRenderer(window, -1, 0);
  
      if (!renderer) {
          SDL_Log("Couldn't create renderer: %s\n",
              SDL_GetError());
          return SDL_FALSE;
      }
  
      SDL_RenderClear(renderer);
  
      srand((unsigned int)time(NULL));
  
      /* Main render loop */
      frames = 0;
      then = SDL_GetTicks();
      done = 0;
  
      SDL_Log("Rendering %i frames offscreen\n", max_frames);
  
  #ifdef __EMSCRIPTEN__
      emscripten_set_main_loop(loop, 0, 1);
  #else
      while (!done && frames < max_frames) {
          ++frames;
          loop();
  
          /* Print out some timing information, along with remaining frames */
          if (frames % (max_frames / 10) == 0) {
              now = SDL_GetTicks();
              if (now > then) {
                  double fps = ((double) frames * 1000) / (now - then);
                  SDL_Log("Frames remaining: %i rendering at %2.2f frames per second\n", max_frames - frames, fps);
              }
          }
      }
  #endif
  
      SDL_DestroyRenderer(renderer);
      SDL_DestroyWindow(window);
      SDL_Quit();
  
      return 0;
  }
  
  /* vi: set ts=4 sw=4 expandtab: */