(svn r10092) -Codechange: code-seperated the spriteloader and blitter from the rest of the code

-Add: make it possible to pick your own blitter (-b <blitter>, -h for overview)
-Add: added a new optimized 8bpp blitter (default, caches sprites of all zoom-levels)
-Add: added a debug 8bpp blitter and a very slow normal 8bpp blitter

src/blitter/8bpp_optimized.cpp

@@ -0,0 +1,199 @@
+#include "../stdafx.h"
+#include "../zoom.hpp"
+#include "../gfx.h"
+#include "../debug.h"
+#include "8bpp_optimized.hpp"
+
+static FBlitter_8bppOptimized iFBlitter_8bppOptimized;
+
+extern void* AllocSprite(size_t);
+
+void Blitter_8bppOptimized::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
+{
+	const byte *src, *src_next;
+	Pixel8 *dst, *dst_line;
+	uint offset = 0;
+
+	/* Find the offset of this zoom-level */
+	offset = ((const byte *)bp->sprite)[(int)zoom * 2] | ((const byte *)bp->sprite)[(int)zoom * 2 + 1] << 8;
+
+	/* Find where to start reading in the source sprite */
+	src = (const byte *)bp->sprite + offset;
+	dst_line = (Pixel8 *)bp->dst + bp->top * bp->pitch + bp->left;
+
+	/* Skip over the top lines in the source image */
+	for (int y = 0; y < bp->skip_top; y++) {
+		uint trans, pixels;
+		for (;;) {
+			trans = *src++;
+			pixels = *src++;
+			if (trans == 0 && pixels == 0) break;
+			src += pixels;
+		}
+	}
+
+	src_next = src;
+
+	for (int y = 0; y < bp->height; y++) {
+		dst = dst_line;
+		dst_line += bp->pitch;
+
+		uint skip_left = bp->skip_left;
+		int width = bp->width;
+
+		for (;;) {
+			src = src_next;
+			uint8 trans = *src++;
+			uint8 pixels = *src++;
+			src_next = src + pixels;
+			if (trans == 0 && pixels == 0) break;
+			if (width <= 0) continue;
+
+			if (skip_left != 0) {
+				if (skip_left < trans) {
+					trans -= skip_left;
+					skip_left = 0;
+				} else {
+					skip_left -= trans;
+					trans = 0;
+				}
+				if (skip_left < pixels) {
+					src += skip_left;
+					pixels -= skip_left;
+					skip_left = 0;
+				} else {
+					src += pixels;
+					skip_left -= pixels;
+					pixels = 0;
+				}
+			}
+			if (skip_left != 0) continue;
+
+			/* Skip transparent pixels */
+			dst += trans;
+			width -= trans;
+			if (width <= 0) continue;
+			if (pixels > width) pixels = width;
+			width -= pixels;
+
+			switch (mode) {
+				case BM_COLOUR_REMAP:
+					for (uint x = 0; x < pixels; x++) {
+						if (bp->remap[*src] != 0) *dst = bp->remap[*src];
+						dst++; src++;
+					}
+					break;
+
+				case BM_TRANSPARENT:
+					for (uint x = 0; x < pixels; x++) {
+						*dst = bp->remap[*dst];
+						dst++; src++;
+					}
+					break;
+
+				default:
+					memcpy(dst, src, pixels);
+					dst += pixels; src += pixels;
+					break;
+			}
+		}
+	}
+}
+
+Sprite *Blitter_8bppOptimized::Encode(SpriteLoader::Sprite *sprite)
+{
+	Sprite *dest_sprite;
+	byte *temp_dst;
+	uint memory = 0;
+	uint index = 0;
+
+	/* Make memory for all zoom-levels */
+	memory += (int)ZOOM_LVL_END * sizeof(uint16);
+	for (int i = 0; i < (int)ZOOM_LVL_END; i++) {
+		memory += UnScaleByZoom(sprite->height, (ZoomLevel)i) * UnScaleByZoom(sprite->width, (ZoomLevel)i);
+		index += 2;
+	}
+
+	/* We have no idea how much memory we really need, so just guess something */
+	memory *= 5;
+	temp_dst = MallocT<byte>(memory);
+
+	/* Make the sprites per zoom-level */
+	for (int i = 0; i < (int)ZOOM_LVL_END; i++) {
+		/* Store the scaled image */
+		const SpriteLoader::CommonPixel *src;
+
+		/* Store the index table */
+		temp_dst[i * 2] = index & 0xFF;
+		temp_dst[i * 2 + 1] = (index >> 8) & 0xFF;
+
+		byte *dst = &temp_dst[index];
+
+		for (int y = 0; y < UnScaleByZoom(sprite->height, (ZoomLevel)i); y++) {
+			uint trans = 0;
+			uint pixels = 0;
+			uint last_color = 0;
+			uint count_index = 0;
+			src = &sprite->data[ScaleByZoom(y, (ZoomLevel)i) * sprite->width];
+
+			for (int x = 0; x < UnScaleByZoom(sprite->width, (ZoomLevel)i); x++) {
+				uint color = 0;
+				int count = 0;
+
+				/* Get the color keeping in mind the zoom-level */
+				for (int j = 0; j < ScaleByZoom(1, (ZoomLevel)i); j++) {
+					if (src->m != 0) { color = src->m; count++; }
+					src++;
+				}
+				/* If more than 12.5% of the pixels are non-transparent, make thisone non-transparent too */
+				if (count < ScaleByZoom(1, (ZoomLevel)i) / 8) color = 0;
+
+				if (last_color == 0 || color == 0) {
+					if (count_index != 0) {
+						/* Write how many non-transparent bytes we get */
+						temp_dst[count_index] = pixels;
+						pixels = 0;
+						count_index = 0;
+					}
+					/* As long as we find transparency bytes, keep counting */
+					if (color == 0) {
+						last_color = 0;
+						trans++;
+						continue;
+					}
+					/* No longer transparency, so write the amount of transparent bytes */
+					*dst = trans;
+					dst++; index++;
+					trans = 0;
+					/* Reserve a byte for the pixel counter */
+					count_index = index;
+					dst++; index++;
+				}
+				last_color = color;
+				pixels++;
+				*dst = color;
+				dst++; index++;
+			}
+
+			if (count_index != 0) temp_dst[count_index] = pixels;
+
+			/* Write line-ending */
+			*dst = 0; dst++; index++;
+			*dst = 0; dst++; index++;
+		}
+	}
+
+	/* Safety check, to make sure we guessed the size correctly */
+	assert(index < memory);
+
+	/* Allocate the exact amount of memory we need */
+	dest_sprite = (Sprite *)AllocSprite(sizeof(*dest_sprite) + index);
+
+	dest_sprite->height = sprite->height;
+	dest_sprite->width  = sprite->width;
+	dest_sprite->x_offs = sprite->x_offs;
+	dest_sprite->y_offs = sprite->y_offs;
+	memcpy(dest_sprite->data, temp_dst, index);
+
+	return dest_sprite;
+}