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Diffstat (limited to 'distrib/sdl-1.2.15/test/testalpha.c')
-rw-r--r--distrib/sdl-1.2.15/test/testalpha.c547
1 files changed, 547 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/test/testalpha.c b/distrib/sdl-1.2.15/test/testalpha.c
new file mode 100644
index 0000000..7e04fbe
--- /dev/null
+++ b/distrib/sdl-1.2.15/test/testalpha.c
@@ -0,0 +1,547 @@
+
+/* Simple program: Fill a colormap with gray and stripe it down the screen,
+ Then move an alpha valued sprite around the screen.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "SDL.h"
+
+#define FRAME_TICKS (1000/30) /* 30 frames/second */
+
+/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
+static void quit(int rc)
+{
+ SDL_Quit();
+ exit(rc);
+}
+
+/* Fill the screen with a gradient */
+static void FillBackground(SDL_Surface *screen)
+{
+ Uint8 *buffer;
+ Uint16 *buffer16;
+ Uint16 color;
+ Uint8 gradient;
+ int i, k;
+
+ /* Set the surface pixels and refresh! */
+ if ( SDL_LockSurface(screen) < 0 ) {
+ fprintf(stderr, "Couldn't lock the display surface: %s\n",
+ SDL_GetError());
+ quit(2);
+ }
+ buffer=(Uint8 *)screen->pixels;
+ if (screen->format->BytesPerPixel!=2) {
+ for ( i=0; i<screen->h; ++i ) {
+ memset(buffer,(i*255)/screen->h, screen->w*screen->format->BytesPerPixel);
+ buffer += screen->pitch;
+ }
+ }
+ else
+ {
+ for ( i=0; i<screen->h; ++i ) {
+ gradient=((i*255)/screen->h);
+ color = (Uint16)SDL_MapRGB(screen->format, gradient, gradient, gradient);
+ buffer16=(Uint16*)buffer;
+ for (k=0; k<screen->w; k++)
+ {
+ *(buffer16+k)=color;
+ }
+ buffer += screen->pitch;
+ }
+ }
+
+ SDL_UnlockSurface(screen);
+ SDL_UpdateRect(screen, 0, 0, 0, 0);
+}
+
+/* Create a "light" -- a yellowish surface with variable alpha */
+SDL_Surface *CreateLight(int radius)
+{
+ Uint8 trans, alphamask;
+ int range, addition;
+ int xdist, ydist;
+ Uint16 x, y;
+ Uint16 skip;
+ Uint32 pixel;
+ SDL_Surface *light;
+
+#ifdef LIGHT_16BIT
+ Uint16 *buf;
+
+ /* Create a 16 (4/4/4/4) bpp square with a full 4-bit alpha channel */
+ /* Note: this isn't any faster than a 32 bit alpha surface */
+ alphamask = 0x0000000F;
+ light = SDL_CreateRGBSurface(SDL_SWSURFACE, 2*radius, 2*radius, 16,
+ 0x0000F000, 0x00000F00, 0x000000F0, alphamask);
+#else
+ Uint32 *buf;
+
+ /* Create a 32 (8/8/8/8) bpp square with a full 8-bit alpha channel */
+ alphamask = 0x000000FF;
+ light = SDL_CreateRGBSurface(SDL_SWSURFACE, 2*radius, 2*radius, 32,
+ 0xFF000000, 0x00FF0000, 0x0000FF00, alphamask);
+ if ( light == NULL ) {
+ fprintf(stderr, "Couldn't create light: %s\n", SDL_GetError());
+ return(NULL);
+ }
+#endif
+
+ /* Fill with a light yellow-orange color */
+ skip = light->pitch-(light->w*light->format->BytesPerPixel);
+#ifdef LIGHT_16BIT
+ buf = (Uint16 *)light->pixels;
+#else
+ buf = (Uint32 *)light->pixels;
+#endif
+ /* Get a tranparent pixel value - we'll add alpha later */
+ pixel = SDL_MapRGBA(light->format, 0xFF, 0xDD, 0x88, 0);
+ for ( y=0; y<light->h; ++y ) {
+ for ( x=0; x<light->w; ++x ) {
+ *buf++ = pixel;
+ }
+ buf += skip; /* Almost always 0, but just in case... */
+ }
+
+ /* Calculate alpha values for the surface. */
+#ifdef LIGHT_16BIT
+ buf = (Uint16 *)light->pixels;
+#else
+ buf = (Uint32 *)light->pixels;
+#endif
+ for ( y=0; y<light->h; ++y ) {
+ for ( x=0; x<light->w; ++x ) {
+ /* Slow distance formula (from center of light) */
+ xdist = x-(light->w/2);
+ ydist = y-(light->h/2);
+ range = (int)sqrt(xdist*xdist+ydist*ydist);
+
+ /* Scale distance to range of transparency (0-255) */
+ if ( range > radius ) {
+ trans = alphamask;
+ } else {
+ /* Increasing transparency with distance */
+ trans = (Uint8)((range*alphamask)/radius);
+
+ /* Lights are very transparent */
+ addition = (alphamask+1)/8;
+ if ( (int)trans+addition > alphamask ) {
+ trans = alphamask;
+ } else {
+ trans += addition;
+ }
+ }
+ /* We set the alpha component as the right N bits */
+ *buf++ |= (255-trans);
+ }
+ buf += skip; /* Almost always 0, but just in case... */
+ }
+ /* Enable RLE acceleration of this alpha surface */
+ SDL_SetAlpha(light, SDL_SRCALPHA|SDL_RLEACCEL, 0);
+
+ /* We're done! */
+ return(light);
+}
+
+static Uint32 flashes = 0;
+static Uint32 flashtime = 0;
+
+void FlashLight(SDL_Surface *screen, SDL_Surface *light, int x, int y)
+{
+ SDL_Rect position;
+ Uint32 ticks1;
+ Uint32 ticks2;
+
+ /* Easy, center light */
+ position.x = x-(light->w/2);
+ position.y = y-(light->h/2);
+ position.w = light->w;
+ position.h = light->h;
+ ticks1 = SDL_GetTicks();
+ SDL_BlitSurface(light, NULL, screen, &position);
+ ticks2 = SDL_GetTicks();
+ SDL_UpdateRects(screen, 1, &position);
+ ++flashes;
+
+ /* Update time spend doing alpha blitting */
+ flashtime += (ticks2-ticks1);
+}
+
+static int sprite_visible = 0;
+static SDL_Surface *sprite;
+static SDL_Surface *backing;
+static SDL_Rect position;
+static int x_vel, y_vel;
+static int alpha_vel;
+
+int LoadSprite(SDL_Surface *screen, char *file)
+{
+ SDL_Surface *converted;
+
+ /* Load the sprite image */
+ sprite = SDL_LoadBMP(file);
+ if ( sprite == NULL ) {
+ fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError());
+ return(-1);
+ }
+
+ /* Set transparent pixel as the pixel at (0,0) */
+ if ( sprite->format->palette ) {
+ SDL_SetColorKey(sprite, SDL_SRCCOLORKEY,
+ *(Uint8 *)sprite->pixels);
+ }
+
+ /* Convert sprite to video format */
+ converted = SDL_DisplayFormat(sprite);
+ SDL_FreeSurface(sprite);
+ if ( converted == NULL ) {
+ fprintf(stderr, "Couldn't convert background: %s\n",
+ SDL_GetError());
+ return(-1);
+ }
+ sprite = converted;
+
+ /* Create the background */
+ backing = SDL_CreateRGBSurface(SDL_SWSURFACE, sprite->w, sprite->h, 8,
+ 0, 0, 0, 0);
+ if ( backing == NULL ) {
+ fprintf(stderr, "Couldn't create background: %s\n",
+ SDL_GetError());
+ SDL_FreeSurface(sprite);
+ return(-1);
+ }
+
+ /* Convert background to video format */
+ converted = SDL_DisplayFormat(backing);
+ SDL_FreeSurface(backing);
+ if ( converted == NULL ) {
+ fprintf(stderr, "Couldn't convert background: %s\n",
+ SDL_GetError());
+ SDL_FreeSurface(sprite);
+ return(-1);
+ }
+ backing = converted;
+
+ /* Set the initial position of the sprite */
+ position.x = (screen->w-sprite->w)/2;
+ position.y = (screen->h-sprite->h)/2;
+ position.w = sprite->w;
+ position.h = sprite->h;
+ x_vel = 0; y_vel = 0;
+ alpha_vel = 1;
+
+ /* We're ready to roll. :) */
+ return(0);
+}
+
+void AttractSprite(Uint16 x, Uint16 y)
+{
+ x_vel = ((int)x-position.x)/10;
+ y_vel = ((int)y-position.y)/10;
+}
+
+void MoveSprite(SDL_Surface *screen, SDL_Surface *light)
+{
+ SDL_Rect updates[2];
+ int alpha;
+
+ /* Erase the sprite if it was visible */
+ if ( sprite_visible ) {
+ updates[0] = position;
+ SDL_BlitSurface(backing, NULL, screen, &updates[0]);
+ } else {
+ updates[0].x = 0; updates[0].y = 0;
+ updates[0].w = 0; updates[0].h = 0;
+ sprite_visible = 1;
+ }
+
+ /* Since the sprite is off the screen, we can do other drawing
+ without being overwritten by the saved area behind the sprite.
+ */
+ if ( light != NULL ) {
+ int x, y;
+
+ SDL_GetMouseState(&x, &y);
+ FlashLight(screen, light, x, y);
+ }
+
+ /* Move the sprite, bounce at the wall */
+ position.x += x_vel;
+ if ( (position.x < 0) || (position.x >= screen->w) ) {
+ x_vel = -x_vel;
+ position.x += x_vel;
+ }
+ position.y += y_vel;
+ if ( (position.y < 0) || (position.y >= screen->h) ) {
+ y_vel = -y_vel;
+ position.y += y_vel;
+ }
+
+ /* Update transparency (fade in and out) */
+ alpha = sprite->format->alpha;
+ if ( (alpha+alpha_vel) < 0 ) {
+ alpha_vel = -alpha_vel;
+ } else
+ if ( (alpha+alpha_vel) > 255 ) {
+ alpha_vel = -alpha_vel;
+ }
+ SDL_SetAlpha(sprite, SDL_SRCALPHA, (Uint8)(alpha+alpha_vel));
+
+ /* Save the area behind the sprite */
+ updates[1] = position;
+ SDL_BlitSurface(screen, &updates[1], backing, NULL);
+
+ /* Blit the sprite onto the screen */
+ updates[1] = position;
+ SDL_BlitSurface(sprite, NULL, screen, &updates[1]);
+
+ /* Make it so! */
+ SDL_UpdateRects(screen, 2, updates);
+}
+
+void WarpSprite(SDL_Surface *screen, int x, int y)
+{
+ SDL_Rect updates[2];
+
+ /* Erase, move, Draw, update */
+ updates[0] = position;
+ SDL_BlitSurface(backing, NULL, screen, &updates[0]);
+ position.x = x-sprite->w/2; /* Center about X */
+ position.y = y-sprite->h/2; /* Center about Y */
+ updates[1] = position;
+ SDL_BlitSurface(screen, &updates[1], backing, NULL);
+ updates[1] = position;
+ SDL_BlitSurface(sprite, NULL, screen, &updates[1]);
+ SDL_UpdateRects(screen, 2, updates);
+}
+
+int main(int argc, char *argv[])
+{
+ const SDL_VideoInfo *info;
+ SDL_Surface *screen;
+ int w, h;
+ Uint8 video_bpp;
+ Uint32 videoflags;
+ int i, done;
+ SDL_Event event;
+ SDL_Surface *light;
+ int mouse_pressed;
+ Uint32 ticks, lastticks;
+
+
+ /* Initialize SDL */
+ if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
+ fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
+ return(1);
+ }
+
+ /* Alpha blending doesn't work well at 8-bit color */
+#ifdef _WIN32_WCE
+ /* Pocket PC */
+ w = 240;
+ h = 320;
+#else
+ w = 640;
+ h = 480;
+#endif
+ info = SDL_GetVideoInfo();
+ if ( info->vfmt->BitsPerPixel > 8 ) {
+ video_bpp = info->vfmt->BitsPerPixel;
+ } else {
+ video_bpp = 16;
+ fprintf(stderr, "forced 16 bpp mode\n");
+ }
+ videoflags = SDL_SWSURFACE;
+ for ( i = 1; argv[i]; ++i ) {
+ if ( strcmp(argv[i], "-bpp") == 0 ) {
+ video_bpp = atoi(argv[++i]);
+ if (video_bpp<=8) {
+ video_bpp=16;
+ fprintf(stderr, "forced 16 bpp mode\n");
+ }
+ } else
+ if ( strcmp(argv[i], "-hw") == 0 ) {
+ videoflags |= SDL_HWSURFACE;
+ } else
+ if ( strcmp(argv[i], "-warp") == 0 ) {
+ videoflags |= SDL_HWPALETTE;
+ } else
+ if ( strcmp(argv[i], "-width") == 0 && argv[i+1] ) {
+ w = atoi(argv[++i]);
+ } else
+ if ( strcmp(argv[i], "-height") == 0 && argv[i+1] ) {
+ h = atoi(argv[++i]);
+ } else
+ if ( strcmp(argv[i], "-resize") == 0 ) {
+ videoflags |= SDL_RESIZABLE;
+ } else
+ if ( strcmp(argv[i], "-noframe") == 0 ) {
+ videoflags |= SDL_NOFRAME;
+ } else
+ if ( strcmp(argv[i], "-fullscreen") == 0 ) {
+ videoflags |= SDL_FULLSCREEN;
+ } else {
+ fprintf(stderr,
+ "Usage: %s [-width N] [-height N] [-bpp N] [-warp] [-hw] [-fullscreen]\n",
+ argv[0]);
+ quit(1);
+ }
+ }
+
+ /* Set video mode */
+ if ( (screen=SDL_SetVideoMode(w,h,video_bpp,videoflags)) == NULL ) {
+ fprintf(stderr, "Couldn't set %dx%dx%d video mode: %s\n",
+ w, h, video_bpp, SDL_GetError());
+ quit(2);
+ }
+ FillBackground(screen);
+
+ /* Create the light */
+ light = CreateLight(82);
+ if ( light == NULL ) {
+ quit(1);
+ }
+
+ /* Load the sprite */
+ if ( LoadSprite(screen, "icon.bmp") < 0 ) {
+ SDL_FreeSurface(light);
+ quit(1);
+ }
+
+ /* Print out information about our surfaces */
+ printf("Screen is at %d bits per pixel\n",screen->format->BitsPerPixel);
+ if ( (screen->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
+ printf("Screen is in video memory\n");
+ } else {
+ printf("Screen is in system memory\n");
+ }
+ if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
+ printf("Screen has double-buffering enabled\n");
+ }
+ if ( (sprite->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
+ printf("Sprite is in video memory\n");
+ } else {
+ printf("Sprite is in system memory\n");
+ }
+
+ /* Run a sample blit to trigger blit acceleration */
+ MoveSprite(screen, NULL);
+ if ( (sprite->flags & SDL_HWACCEL) == SDL_HWACCEL ) {
+ printf("Sprite blit uses hardware alpha acceleration\n");
+ } else {
+ printf("Sprite blit dosn't uses hardware alpha acceleration\n");
+ }
+
+ /* Set a clipping rectangle to clip the outside edge of the screen */
+ { SDL_Rect clip;
+ clip.x = 32;
+ clip.y = 32;
+ clip.w = screen->w-(2*32);
+ clip.h = screen->h-(2*32);
+ SDL_SetClipRect(screen, &clip);
+ }
+
+ /* Wait for a keystroke */
+ lastticks = SDL_GetTicks();
+ done = 0;
+ mouse_pressed = 0;
+ while ( !done ) {
+ /* Update the frame -- move the sprite */
+ if ( mouse_pressed ) {
+ MoveSprite(screen, light);
+ mouse_pressed = 0;
+ } else {
+ MoveSprite(screen, NULL);
+ }
+
+ /* Slow down the loop to 30 frames/second */
+ ticks = SDL_GetTicks();
+ if ( (ticks-lastticks) < FRAME_TICKS ) {
+#ifdef CHECK_SLEEP_GRANULARITY
+fprintf(stderr, "Sleeping %d ticks\n", FRAME_TICKS-(ticks-lastticks));
+#endif
+ SDL_Delay(FRAME_TICKS-(ticks-lastticks));
+#ifdef CHECK_SLEEP_GRANULARITY
+fprintf(stderr, "Slept %d ticks\n", (SDL_GetTicks()-ticks));
+#endif
+ }
+ lastticks = ticks;
+
+ /* Check for events */
+ while ( SDL_PollEvent(&event) ) {
+ switch (event.type) {
+ case SDL_VIDEORESIZE:
+ screen = SDL_SetVideoMode(event.resize.w, event.resize.h, video_bpp, videoflags);
+ if ( screen ) {
+ FillBackground(screen);
+ }
+ break;
+ /* Attract sprite while mouse is held down */
+ case SDL_MOUSEMOTION:
+ if (event.motion.state != 0) {
+ AttractSprite(event.motion.x,
+ event.motion.y);
+ mouse_pressed = 1;
+ }
+ break;
+ case SDL_MOUSEBUTTONDOWN:
+ if ( event.button.button == 1 ) {
+ AttractSprite(event.button.x,
+ event.button.y);
+ mouse_pressed = 1;
+ } else {
+ SDL_Rect area;
+
+ area.x = event.button.x-16;
+ area.y = event.button.y-16;
+ area.w = 32;
+ area.h = 32;
+ SDL_FillRect(screen, &area, 0);
+ SDL_UpdateRects(screen,1,&area);
+ }
+ break;
+ case SDL_KEYDOWN:
+#ifdef _WIN32_WCE
+ // there is no ESC key at all
+ done = 1;
+#else
+ if ( event.key.keysym.sym == SDLK_ESCAPE ) {
+ done = 1;
+ } else if (event.key.keysym.sym == SDLK_t) {
+ videoflags ^= SDL_FULLSCREEN;
+ screen = SDL_SetVideoMode(w, h, video_bpp, videoflags);
+ if ( screen == NULL ) {
+ fprintf(stderr, "Couldn't toggle video mode: %s\n",
+ SDL_GetError());
+ quit(2);
+ }
+ FillBackground(screen);
+ }
+#endif
+
+ break;
+ case SDL_QUIT:
+ done = 1;
+ break;
+ default:
+ break;
+ }
+ }
+ }
+ SDL_FreeSurface(light);
+ SDL_FreeSurface(sprite);
+ SDL_FreeSurface(backing);
+
+ /* Print out some timing information */
+ if ( flashes > 0 ) {
+ printf("%d alpha blits, ~%4.4f ms per blit\n",
+ flashes, (float)flashtime/flashes);
+ }
+
+ SDL_Quit();
+ return(0);
+}
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