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/* $Id$ */

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/** @file 32bpp_optimized.cpp Implementation of the optimized 32 bpp blitter. */

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#include "../stdafx.h"

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#include "../zoom_func.h"

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#include "../gfx_func.h"

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#include "../debug.h"

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#include "32bpp_optimized.hpp"

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static FBlitter_32bppOptimized iFBlitter_32bppOptimized;

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void Blitter_32bppOptimized::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)

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{

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	const SpriteLoader::CommonPixel *src, *src_line;

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	uint32 *dst, *dst_line;

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	/* Find where to start reading in the source sprite */

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	src_line = (const SpriteLoader::CommonPixel *)bp->sprite + (bp->skip_top * bp->sprite_width + bp->skip_left) * ScaleByZoom(1, zoom);

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	dst_line = (uint32 *)bp->dst + bp->top * bp->pitch + bp->left;

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	for (int y = 0; y < bp->height; y++) {

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		dst = dst_line;

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		dst_line += bp->pitch;

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		src = src_line;

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		src_line += bp->sprite_width * ScaleByZoom(1, zoom);

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		for (int x = 0; x < bp->width; x++) {

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			if (src->a == 0) {

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				/* src->r is 'misused' here to indicate how much more pixels are following with an alpha of 0 */

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				int skip = UnScaleByZoom(src->r, zoom);

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				dst += skip;

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				x   += skip - 1;

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				src += ScaleByZoom(1, zoom) * skip;

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				continue;

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			}

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			switch (mode) {

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				case BM_COLOUR_REMAP:

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					/* In case the m-channel is zero, do not remap this pixel in any way */

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					if (src->m == 0) {

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						*dst = ComposeColourRGBA(src->r, src->g, src->b, src->a, *dst);

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					} else {

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						if (bp->remap[src->m] != 0) *dst = ComposeColourPA(this->LookupColourInPalette(bp->remap[src->m]), src->a, *dst);

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					}

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					break;

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				case BM_TRANSPARENT:

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					/* TODO -- We make an assumption here that the remap in fact is transparency, not some color.

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					 *  This is never a problem with the code we produce, but newgrfs can make it fail... or at least:

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					 *  we produce a result the newgrf maker didn't expect ;) */

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					/* Make the current color a bit more black, so it looks like this image is transparent */

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					*dst = MakeTransparent(*dst, 192);

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					break;

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				default:

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					*dst = ComposeColourRGBA(src->r, src->g, src->b, src->a, *dst);

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					break;

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			}

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			dst++;

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			src += ScaleByZoom(1, zoom);

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		}

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	}

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}

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Sprite *Blitter_32bppOptimized::Encode(SpriteLoader::Sprite *sprite, Blitter::AllocatorProc *allocator)

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{

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	Sprite *dest_sprite;

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	SpriteLoader::CommonPixel *dst;

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	dest_sprite = (Sprite *)allocator(sizeof(*dest_sprite) + sprite->height * sprite->width * sizeof(SpriteLoader::CommonPixel));

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	dest_sprite->height = sprite->height;

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	dest_sprite->width  = sprite->width;

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	dest_sprite->x_offs = sprite->x_offs;

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	dest_sprite->y_offs = sprite->y_offs;

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	dst = (SpriteLoader::CommonPixel *)dest_sprite->data;

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	memcpy(dst, sprite->data, sprite->height * sprite->width * sizeof(SpriteLoader::CommonPixel));

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	/* Skip to the end of the array, and work backwards to find transparent blocks */

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	dst = dst + sprite->height * sprite->width - 1;

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	for (uint y = sprite->height; y > 0; y--) {

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		int trans = 0;

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		/* Process sprite line backwards, to compute lengths of transparent blocks */

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		for (uint x = sprite->width; x > 0; x--) {

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			if (dst->a == 0) {

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				/* Save transparent block length in red channel; max value is 255 the red channel can contain */

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				if (trans < 255) trans++;

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				dst->r = trans;

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				dst->g = 0;

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				dst->b = 0;

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				dst->m = 0;

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			} else {

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				trans = 0;

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				if (dst->m != 0) {

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					/* Pre-convert the mapping channel to a RGB value */

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					uint color = this->LookupColourInPalette(dst->m);

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					dst->r = GB(color, 16, 8);

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					dst->g = GB(color, 8,  8);

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					dst->b = GB(color, 0,  8);

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				}

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			}

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			dst--;

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		}

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	}

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	return dest_sprite;

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}