Improve Android pause/resume behavior.

Xcode-iOS/Demos/src/happy.c

@@ -0,0 +1,177 @@
+/*
+ *  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;
+
+}