kc3-lang/SDL/Xcode-iOS/Demos/src/happy.c

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• Hash : 0e45984f
  Author :
  Date : 2015-06-21T17:33:46
  

  Fixed crash if initialization of EGL failed but was tried again later. The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly uninitialized data structure if loading the library first failed. A later try to use EGL then skipped initialization and assumed it was previously successful because the data structure now already existed. This led to at least one crash in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was dereferenced to make a call to eglBindAPI().

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• Xcode-iOS/Demos/src/happy.c

• /*
   *  happy.c
   *  written by Holmes Futrell
   *  use however you want
   */
  
  #include "SDL.h"
  #include "common.h"
  
  #define NUM_HAPPY_FACES 100     /* number of faces to draw */
  #define MILLESECONDS_PER_FRAME 16       /* about 60 frames per second */
  #define HAPPY_FACE_SIZE 32      /* width and height of happyface (pixels) */
  
  static SDL_Texture *texture = 0;    /* reference to texture holding happyface */
  
  static struct
  {
      float x, y;                 /* position of happyface */
      float xvel, yvel;           /* velocity of happyface */
  } faces[NUM_HAPPY_FACES];
  
  /*
      Sets initial positions and velocities of happyfaces
      units of velocity are pixels per millesecond
  */
  void
  initializeHappyFaces()
  {
      int i;
      for (i = 0; i < NUM_HAPPY_FACES; i++) {
          faces[i].x = randomFloat(0.0f, SCREEN_WIDTH - HAPPY_FACE_SIZE);
          faces[i].y = randomFloat(0.0f, SCREEN_HEIGHT - HAPPY_FACE_SIZE);
          faces[i].xvel = randomFloat(-0.1f, 0.1f);
          faces[i].yvel = randomFloat(-0.1f, 0.1f);
      }
  }
  
  void
  render(SDL_Renderer *renderer)
  {
  
      int i;
      SDL_Rect srcRect;
      SDL_Rect dstRect;
  
      /* setup boundaries for happyface bouncing */
      Uint16 maxx = SCREEN_WIDTH - HAPPY_FACE_SIZE;
      Uint16 maxy = SCREEN_HEIGHT - HAPPY_FACE_SIZE;
      Uint16 minx = 0;
      Uint16 miny = 0;
  
      /* setup rects for drawing */
      srcRect.x = 0;
      srcRect.y = 0;
      srcRect.w = HAPPY_FACE_SIZE;
      srcRect.h = HAPPY_FACE_SIZE;
      dstRect.w = HAPPY_FACE_SIZE;
      dstRect.h = HAPPY_FACE_SIZE;
  
      /* fill background in with black */
      SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
      SDL_RenderClear(renderer);
  
      /*
         loop through all the happy faces:
         - update position
         - update velocity (if boundary is hit)
         - draw
       */
      for (i = 0; i < NUM_HAPPY_FACES; i++) {
          faces[i].x += faces[i].xvel * MILLESECONDS_PER_FRAME;
          faces[i].y += faces[i].yvel * MILLESECONDS_PER_FRAME;
          if (faces[i].x > maxx) {
              faces[i].x = maxx;
              faces[i].xvel = -faces[i].xvel;
          } else if (faces[i].y > maxy) {
              faces[i].y = maxy;
              faces[i].yvel = -faces[i].yvel;
          }
          if (faces[i].x < minx) {
              faces[i].x = minx;
              faces[i].xvel = -faces[i].xvel;
          } else if (faces[i].y < miny) {
              faces[i].y = miny;
              faces[i].yvel = -faces[i].yvel;
          }
          dstRect.x = faces[i].x;
          dstRect.y = faces[i].y;
          SDL_RenderCopy(renderer, texture, &srcRect, &dstRect);
      }
      /* update screen */
      SDL_RenderPresent(renderer);
  
  }
  
  /*
      loads the happyface graphic into a texture
  */
  void
  initializeTexture(SDL_Renderer *renderer)
  {
      SDL_Surface *bmp_surface;
      /* load the bmp */
      bmp_surface = SDL_LoadBMP("icon.bmp");
      if (bmp_surface == NULL) {
          fatalError("could not load bmp");
      }
      /* set white to transparent on the happyface */
      SDL_SetColorKey(bmp_surface, 1,
                      SDL_MapRGB(bmp_surface->format, 255, 255, 255));
  
      /* convert RGBA surface to texture */
      texture = SDL_CreateTextureFromSurface(renderer, bmp_surface);
      if (texture == 0) {
          fatalError("could not create texture");
      }
      SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
  
      /* free up allocated memory */
      SDL_FreeSurface(bmp_surface);
  }
  
  int
  main(int argc, char *argv[])
  {
  
      SDL_Window *window;
      SDL_Renderer *renderer;
      Uint32 startFrame;
      Uint32 endFrame;
      Uint32 delay;
      int done;
  
      /* initialize SDL */
      if (SDL_Init(SDL_INIT_VIDEO) < 0) {
          fatalError("Could not initialize SDL");
      }
      window = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,
                                  SDL_WINDOW_OPENGL |
                                  SDL_WINDOW_BORDERLESS);
  
      renderer = SDL_CreateRenderer(window, -1, 0);
  
      initializeTexture(renderer);
      initializeHappyFaces();
  
      /* main loop */
      done = 0;
      while (!done) {
          startFrame = SDL_GetTicks();
          SDL_Event event;
          while (SDL_PollEvent(&event)) {
              if (event.type == SDL_QUIT) {
                  done = 1;
              }
          }
          render(renderer);
          endFrame = SDL_GetTicks();
  
          /* figure out how much time we have left, and then sleep */
          delay = MILLESECONDS_PER_FRAME - (endFrame - startFrame);
          if (delay < 0) {
              delay = 0;
          } else if (delay > MILLESECONDS_PER_FRAME) {
              delay = MILLESECONDS_PER_FRAME;
          }
          SDL_Delay(delay);
      }
  
      /* cleanup */
      SDL_DestroyTexture(texture);
      /* shutdown SDL */
      SDL_Quit();
  
      return 0;
  
  }
  

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