Happy faces demo (bitmaps)

libsdl-org · Jul 18, 2008 · d5e3733 · d5e3733
1 parent 12295a3
commit d5e3733
Showing 1 changed file with 179 additions and 0 deletions.
diff --git a/XCodeiPhoneOS/Demos/src/happy.c b/XCodeiPhoneOS/Demos/src/happy.c
@@ -0,0 +1,179 @@
+/*
+ *	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_TextureID texture_id = 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(void) {
+
+	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_RenderFill(0, 0, 0, 255, NULL);
+
+	/*
+	   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(texture_id, &srcRect, &dstRect);
+	}
+	/* update screen */
+	SDL_RenderPresent();
+
+}
+
+/*
+	loads the happyface graphic into a texture
+*/
+void initializeTexture() {
+	SDL_Surface *bmp_surface;
+	SDL_Surface *bmp_surface_rgba;
+	int format = SDL_PIXELFORMAT_ABGR8888; /* desired texture format */
+	Uint32 Rmask, Gmask, Bmask, Amask;	   /* masks for desired format */
+	int bpp;							   /* bits per pixel for desired format */
+	/* 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));
+	SDL_PixelFormatEnumToMasks(format, &bpp, &Rmask, &Gmask, &Bmask, &Amask);
+	/*
+	   create a new RGBA surface and blit the bmp to it
+	   this is an extra step, but it seems to be necessary
+	   is this a bug?
+	 */
+	bmp_surface_rgba = SDL_CreateRGBSurface(0, bmp_surface->w, bmp_surface->h, bpp, Rmask, Gmask, Bmask, Amask);	
+	SDL_BlitSurface(bmp_surface, NULL, bmp_surface_rgba, NULL);
+
+	/* convert RGBA surface to texture */
+	texture_id = SDL_CreateTextureFromSurface(format, bmp_surface_rgba);
+	if (texture_id == 0) {
+		fatalError("could not create texture");
+	}
+	SDL_SetTextureBlendMode(texture_id, SDL_TEXTUREBLENDMODE_BLEND);
+
+	/* free up allocated memory */
+	SDL_FreeSurface(bmp_surface_rgba);
+	SDL_FreeSurface(bmp_surface);
+}
+
+int main(int argc, char *argv[]) {
+
+	SDL_WindowID windowID;
+	Uint32 startFrame;
+	Uint32 endFrame;
+	Uint32 delay;
+	int done;
+
+	/* initialize SDL */
+	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
+		fatalError("Could not initialize SDL");
+	}
+	windowID = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,\
+								SDL_WINDOW_OPENGL|SDL_WINDOW_SHOWN|SDL_WINDOW_BORDERLESS);
+
+	SDL_CreateRenderer(windowID, -1, 0);
+
+	initializeTexture();
+	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();
+		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_id);
+	/* shutdown SDL */
+	SDL_Quit();
+
+	return 0;
+
+}