Begin mask support

svn path=/import/jshaw/libsprite/; revision=9994

3 files changed, 47 insertions, 23 deletions

diff --git a/trunk/example.c b/trunk/example.c
index d1d8853..bdd12b4 100644
--- a/trunk/example.c
+++ b/trunk/example.c
@@ -7,8 +7,14 @@
 /* color is 0xrrggbbaa */
 void sdl_draw_pixel(SDL_Surface* surface, uint32_t x, uint32_t y, uint32_t color)
 {
-	uint32_t mapped_color = SDL_MapRGB(surface->format, (color & 0xff000000) >> 24, (color & 0x00ff0000) >> 16, (color & 0x0000ff00) >> 8);
 	uint32_t* pixel = ((uint32_t*) (surface->pixels)) + (y * surface->pitch/4) + x;
+	/* pretty sure SDL can do this, but can't figure out how */
+	uint32_t alpha = 0xff;/*color & 0x000000ff;*/
+	uint32_t r = ((color & 0xff000000) >> 24) * (alpha / 256.0);
+	uint32_t g = ((color & 0x00ff0000) >> 16) * (alpha / 256.0);
+	uint32_t b = ((color & 0x0000ff00) >> 8) * (alpha / 256.0);
+	uint32_t mapped_color = SDL_MapRGBA(surface->format, r, g, b, alpha);
+	
 	*pixel = mapped_color;
 }
 
@@ -50,7 +56,8 @@ int main(int argc, char *argv[])
 	printf("extension_size %u\n", sprite_area->extension_size);
 
 	SDL_Surface *screen;
-	screen = SDL_SetVideoMode(800, 600, 32, SDL_SWSURFACE);
+	screen = SDL_SetVideoMode(800, 600, 32, SDL_ANYFORMAT);
+	SDL_SetAlpha(screen, SDL_SRCALPHA, 0);
 
 	for (uint32_t i = 0; i < sprite_area->sprite_count; i++) {
 		struct sprite* sprite = sprite_area->sprites[i];
@@ -65,8 +72,8 @@ int main(int argc, char *argv[])
 		printf("hasPalette %s\n", sprite->has_palette ? "YES" : "NO");
 		if (sprite->has_palette) printf("paletteSize %u\n", sprite->palettesize);
 
-		printf("hasMask %s\n", sprite->hasmask ? "YES" : "NO");
-		if (sprite->hasmask) printf("maskbpp %u\n", sprite->mode->maskbpp);
+		printf("hasMask %s\n", sprite->has_mask ? "YES" : "NO");
+		if (sprite->has_mask) printf("maskbpp %u\n", sprite->mode->maskbpp);
 
 		sdl_blank(screen);
 
@@ -76,7 +83,7 @@ int main(int argc, char *argv[])
 			}
 		}
 
-		SDL_UpdateRect(screen, 0, 0, 799, 599);
+		SDL_UpdateRect(screen, 0, 0, 0, 0);
 		fgetc(stdin);
 	}
 
diff --git a/trunk/libsprite.c b/trunk/libsprite.c
index f52e200..2120f94 100644
--- a/trunk/libsprite.c
+++ b/trunk/libsprite.c
@@ -18,6 +18,12 @@ struct sprite_header {
 	uint32_t first_used_bit; /* old format only (spriteType = 0) */
 	uint32_t last_used_bit;
 	uint32_t image_size; /* bytes */
+	uint32_t mask_size;
+};
+
+struct sprite_mask_state {
+	uint32_t x;
+	uint32_t y;
 };
 
 static struct sprite_mode oldmodes[256];
@@ -331,6 +337,16 @@ uint32_t sprite_upscale_color(uint32_t pixel, struct sprite_mode* mode)
 	}
 }
 
+/* Get the next mask byte.
+ * Mask of 0xff denotes 100% opaque, 0x00 denotes 100% transparent
+ */
+uint8_t sprite_get_mask(struct sprite* sprite, struct sprite_header* header, struct sprite_mask_state* mask_state)
+{
+	/* a 1bpp mask (for new mode sprites), each row is word aligned (therefore potential righthand wastage */
+	sprite = sprite; header = header; mask_state = mask_state;
+	return 0xff;
+}
+
 void sprite_load_high_color(uint8_t* image_in, uint8_t* mask, struct sprite* sprite, struct sprite_header* header)
 {
 	mask = mask;
@@ -440,22 +456,20 @@ struct sprite* sprite_load_sprite(FILE* spritefile)
 	sprite->palettesize     = imageOffset - 44;
 	sprite->has_palette     = (sprite->palettesize > 0);
 
-	uint32_t image_size;
-	uint32_t maskSize;
 
+	/* sprite has no mask if imageOffset == maskOffset */
 	if (imageOffset == maskOffset) {
-		sprite->hasmask = false;
-		image_size = nextSpriteOffset - 44 - sprite->palettesize;
-		maskSize  = 0;
+		sprite->has_mask   = false;
+		header->image_size = nextSpriteOffset - 44 - sprite->palettesize;
+		header->mask_size  = 0;
 	} else {
-		sprite->hasmask   = true;
-		image_size = maskOffset - imageOffset;
-		maskSize  = nextSpriteOffset - 44 - sprite->palettesize - image_size;
+		sprite->has_mask   = true;
+		header->image_size = maskOffset - imageOffset;
+		header->mask_size  = nextSpriteOffset - 44 - sprite->palettesize - header->image_size;
 	}
 
-	header->image_size = image_size;
-
-	if (sprite->hasmask) LOGDBG("maskSize %u\n", maskSize);
+	if (sprite->has_mask) LOGDBG("mask_size (bits) %u\n", header->mask_size * 8);
+	if (sprite->has_mask) LOGDBG("	w*h %u\n", sprite->width * sprite->height);
 	
 	if (sprite->has_palette) {
 		assert(sprite->palettesize % 8 == 0);
@@ -478,15 +492,18 @@ struct sprite* sprite_load_sprite(FILE* spritefile)
 		}
 	}
 
-	uint8_t* image = malloc(image_size);
-	sprite_read_bytes(spritefile, image, image_size);
+	uint8_t* image = malloc(header->image_size);
+	sprite_read_bytes(spritefile, image, header->image_size);
 
-	uint8_t* mask = malloc(maskSize);
-	sprite_read_bytes(spritefile, mask, maskSize);
+	uint8_t* mask = NULL;
+	if (sprite->has_mask) {
+		mask = malloc(header->mask_size);
+		sprite_read_bytes(spritefile, mask, header->mask_size);
+	}
 
-	/* sanity check imageSize */
+	/* sanity check image_size */
 	assert((header->width_words) * 4 * (sprite->height) == header->image_size);
-	/* TODO: sanity check maskSize */
+	/* TODO: sanity check mask_size */
 	if (sprite->mode->colorbpp > 8) {
 		sprite_load_high_color(image, mask, sprite, header);
 	} else {
diff --git a/trunk/libsprite.h b/trunk/libsprite.h
index 3fdc6c8..8d89631 100644
--- a/trunk/libsprite.h
+++ b/trunk/libsprite.h
@@ -30,7 +30,7 @@ struct sprite_palette {
 struct sprite {
 	unsigned char name[13]; /* last byte for 0 terminator */
 	struct sprite_mode* mode;
-	bool hasmask;
+	bool has_mask;
 	bool has_palette;
 	uint32_t palettesize; /* in number of entries (each entry is a word) */
 	uint32_t* palette;