+void SDLFadeRectangle(Bitmap *bitmap_cross, int x, int y, int width, int height,
+ int fade_mode, int fade_delay, int post_delay,
+ void (*draw_border_function)(void))
+{
+ SDL_Surface *surface_source = gfx.fade_bitmap_source->surface;
+ SDL_Surface *surface_target = gfx.fade_bitmap_target->surface;
+ SDL_Surface *surface_black = gfx.fade_bitmap_black->surface;
+ SDL_Surface *surface_screen = backbuffer->surface;
+ SDL_Surface *surface_cross = (bitmap_cross ? bitmap_cross->surface : NULL);
+ SDL_Rect src_rect, dst_rect;
+ SDL_Rect dst_rect2;
+ int src_x = x, src_y = y;
+ int dst_x = x, dst_y = y;
+ unsigned int time_last, time_current;
+
+ // store function for drawing global masked border
+ void (*draw_global_border_function)(int) = gfx.draw_global_border_function;
+
+ // deactivate drawing of global border while fading, if needed
+ if (draw_border_function == NULL)
+ gfx.draw_global_border_function = NULL;
+
+ src_rect.x = src_x;
+ src_rect.y = src_y;
+ src_rect.w = width;
+ src_rect.h = height;
+
+ dst_x += video_xoffset;
+ dst_y += video_yoffset;
+
+ dst_rect.x = dst_x;
+ dst_rect.y = dst_y;
+ dst_rect.w = width; /* (ignored) */
+ dst_rect.h = height; /* (ignored) */
+
+ dst_rect2 = dst_rect;
+
+ /* copy source and target surfaces to temporary surfaces for fading */
+ if (fade_mode & FADE_TYPE_TRANSFORM)
+ {
+ SDL_BlitSurface(surface_cross, &src_rect, surface_source, &src_rect);
+ SDL_BlitSurface(surface_screen, &dst_rect, surface_target, &src_rect);
+ }
+ else if (fade_mode & FADE_TYPE_FADE_IN)
+ {
+ SDL_BlitSurface(surface_black, &src_rect, surface_source, &src_rect);
+ SDL_BlitSurface(surface_screen, &dst_rect, surface_target, &src_rect);
+ }
+ else /* FADE_TYPE_FADE_OUT */
+ {
+ SDL_BlitSurface(surface_screen, &dst_rect, surface_source, &src_rect);
+ SDL_BlitSurface(surface_black, &src_rect, surface_target, &src_rect);
+ }
+
+ time_current = SDL_GetTicks();
+
+ if (fade_mode == FADE_MODE_MELT)
+ {
+ boolean done = FALSE;
+ int melt_pixels = 2;
+ int melt_columns = width / melt_pixels;
+ int ypos[melt_columns];
+ int max_steps = height / 8 + 32;
+ int steps_done = 0;
+ float steps = 0;
+ int i;
+
+ SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
+#if defined(TARGET_SDL2)
+ SDL_SetSurfaceBlendMode(surface_target, SDL_BLENDMODE_NONE);
+#else
+ SDL_SetAlpha(surface_target, 0, 0); /* disable alpha blending */
+#endif
+
+ ypos[0] = -GetSimpleRandom(16);
+
+ for (i = 1 ; i < melt_columns; i++)
+ {
+ int r = GetSimpleRandom(3) - 1; /* randomly choose from { -1, 0, -1 } */
+
+ ypos[i] = ypos[i - 1] + r;
+
+ if (ypos[i] > 0)
+ ypos[i] = 0;
+ else
+ if (ypos[i] == -16)
+ ypos[i] = -15;
+ }
+
+ while (!done)
+ {
+ int steps_final;
+
+ time_last = time_current;
+ time_current = SDL_GetTicks();
+ steps += max_steps * ((float)(time_current - time_last) / fade_delay);
+ steps_final = MIN(MAX(0, steps), max_steps);
+
+ steps_done++;
+
+ done = (steps_done >= steps_final);
+
+ for (i = 0 ; i < melt_columns; i++)
+ {
+ if (ypos[i] < 0)
+ {
+ ypos[i]++;
+
+ done = FALSE;
+ }
+ else if (ypos[i] < height)
+ {
+ int y1 = 16;
+ int y2 = 8;
+ int y3 = 8;
+ int dy = (ypos[i] < y1) ? ypos[i] + 1 : y2 + GetSimpleRandom(y3);
+
+ if (ypos[i] + dy >= height)
+ dy = height - ypos[i];
+
+ /* copy part of (appearing) target surface to upper area */
+ src_rect.x = src_x + i * melt_pixels;
+ // src_rect.y = src_y + ypos[i];
+ src_rect.y = src_y;
+ src_rect.w = melt_pixels;
+ // src_rect.h = dy;
+ src_rect.h = ypos[i] + dy;
+
+ dst_rect.x = dst_x + i * melt_pixels;
+ // dst_rect.y = dst_y + ypos[i];
+ dst_rect.y = dst_y;
+
+ if (steps_done >= steps_final)
+ SDL_BlitSurface(surface_target, &src_rect,
+ surface_screen, &dst_rect);
+
+ ypos[i] += dy;
+
+ /* copy part of (disappearing) source surface to lower area */
+ src_rect.x = src_x + i * melt_pixels;
+ src_rect.y = src_y;
+ src_rect.w = melt_pixels;
+ src_rect.h = height - ypos[i];
+
+ dst_rect.x = dst_x + i * melt_pixels;
+ dst_rect.y = dst_y + ypos[i];
+
+ if (steps_done >= steps_final)
+ SDL_BlitSurface(surface_source, &src_rect,
+ surface_screen, &dst_rect);
+
+ done = FALSE;
+ }
+ else
+ {
+ src_rect.x = src_x + i * melt_pixels;
+ src_rect.y = src_y;
+ src_rect.w = melt_pixels;
+ src_rect.h = height;
+
+ dst_rect.x = dst_x + i * melt_pixels;
+ dst_rect.y = dst_y;
+
+ if (steps_done >= steps_final)
+ SDL_BlitSurface(surface_target, &src_rect,
+ surface_screen, &dst_rect);
+ }
+ }
+
+ if (steps_done >= steps_final)
+ {
+ if (draw_border_function != NULL)
+ draw_border_function();
+
+ UpdateScreen(&dst_rect2);
+ }
+ }
+ }
+ else if (fade_mode == FADE_MODE_CURTAIN)
+ {
+ float xx;
+ int xx_final;
+ int xx_size = width / 2;
+
+ SDL_BlitSurface(surface_target, &src_rect, surface_screen, &dst_rect);
+#if defined(TARGET_SDL2)
+ SDL_SetSurfaceBlendMode(surface_source, SDL_BLENDMODE_NONE);
+#else
+ SDL_SetAlpha(surface_source, 0, 0); /* disable alpha blending */
+#endif
+
+ for (xx = 0; xx < xx_size;)
+ {
+ time_last = time_current;
+ time_current = SDL_GetTicks();
+ xx += xx_size * ((float)(time_current - time_last) / fade_delay);
+ xx_final = MIN(MAX(0, xx), xx_size);
+
+ src_rect.x = src_x;
+ src_rect.y = src_y;
+ src_rect.w = width;
+ src_rect.h = height;
+
+ dst_rect.x = dst_x;
+ dst_rect.y = dst_y;
+
+ /* draw new (target) image to screen buffer */
+ SDL_BlitSurface(surface_target, &src_rect, surface_screen, &dst_rect);
+
+ if (xx_final < xx_size)
+ {
+ src_rect.w = xx_size - xx_final;
+ src_rect.h = height;
+
+ /* draw old (source) image to screen buffer (left side) */
+
+ src_rect.x = src_x + xx_final;
+ dst_rect.x = dst_x;
+
+ SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
+
+ /* draw old (source) image to screen buffer (right side) */
+
+ src_rect.x = src_x + xx_size;
+ dst_rect.x = dst_x + xx_size + xx_final;
+
+ SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
+ }
+
+ if (draw_border_function != NULL)
+ draw_border_function();
+
+ /* only update the region of the screen that is affected from fading */
+ UpdateScreen(&dst_rect2);
+ }
+ }
+ else /* fading in, fading out or cross-fading */
+ {
+ float alpha;
+ int alpha_final;
+
+ for (alpha = 0.0; alpha < 255.0;)
+ {
+ time_last = time_current;
+ time_current = SDL_GetTicks();
+ alpha += 255 * ((float)(time_current - time_last) / fade_delay);
+ alpha_final = MIN(MAX(0, alpha), 255);
+
+ /* draw existing (source) image to screen buffer */
+ SDL_BlitSurface(surface_source, &src_rect, surface_screen, &dst_rect);
+
+ /* draw new (target) image to screen buffer using alpha blending */
+#if defined(TARGET_SDL2)
+ SDL_SetSurfaceAlphaMod(surface_target, alpha_final);
+ SDL_SetSurfaceBlendMode(surface_target, SDL_BLENDMODE_BLEND);
+#else
+ SDL_SetAlpha(surface_target, SDL_SRCALPHA, alpha_final);
+#endif
+ SDL_BlitSurface(surface_target, &src_rect, surface_screen, &dst_rect);
+
+ if (draw_border_function != NULL)
+ draw_border_function();
+
+ /* only update the region of the screen that is affected from fading */
+ UpdateScreen(&dst_rect);
+ }
+ }
+
+ if (post_delay > 0)
+ {
+ unsigned int time_post_delay;
+
+ time_current = SDL_GetTicks();
+ time_post_delay = time_current + post_delay;
+
+ while (time_current < time_post_delay)
+ {
+ // do not wait longer than 10 ms at a time to be able to ...
+ Delay(MIN(10, time_post_delay - time_current));
+
+ // ... continue drawing global animations during post delay
+ UpdateScreen(NULL);
+
+ time_current = SDL_GetTicks();
+ }
+ }
+
+ // restore function for drawing global masked border
+ gfx.draw_global_border_function = draw_global_border_function;