# 8bpp_optimized.cpp

Go to the documentation of this file.

    00001 /* $Id: 8bpp_optimized.cpp 15556 2009-02-23 17:54:02Z rubidium $ */
    00002
    00005 #include "../stdafx.h"
    00006 #include "../zoom_func.h"
    00007 #include "../core/alloc_func.hpp"
    00008 #include "../core/math_func.hpp"
    00009 #include "8bpp_optimized.hpp"
    00010
    00011 static FBlitter_8bppOptimized iFBlitter_8bppOptimized;
    00012
    00013 void Blitter_8bppOptimized::Draw(Blitter::BlitterParams *bp, BlitterMode mode, ZoomLevel zoom)
    00014 {
    00015   /* Find the offset of this zoom-level */
    00016   const SpriteData *sprite_src = (const SpriteData *)bp->sprite;
    00017   uint offset = sprite_src->offset[zoom];
    00018
    00019   /* Find where to start reading in the source sprite */
    00020   const uint8 *src = sprite_src->data + offset;
    00021   uint8 *dst_line = (uint8 *)bp->dst + bp->top * bp->pitch + bp->left;
    00022
    00023   /* Skip over the top lines in the source image */
    00024   for (int y = 0; y < bp->skip_top; y++) {
    00025     for (;;) {
    00026       uint trans = *src++;
    00027       uint pixels = *src++;
    00028       if (trans == 0 && pixels == 0) break;
    00029       src += pixels;
    00030     }
    00031   }
    00032
    00033   const uint8 *src_next = src;
    00034
    00035   for (int y = 0; y < bp->height; y++) {
    00036     uint8 *dst = dst_line;
    00037     dst_line += bp->pitch;
    00038
    00039     uint skip_left = bp->skip_left;
    00040     int width = bp->width;
    00041
    00042     for (;;) {
    00043       src = src_next;
    00044       uint trans = *src++;
    00045       uint pixels = *src++;
    00046       src_next = src + pixels;
    00047       if (trans == 0 && pixels == 0) break;
    00048       if (width <= 0) continue;
    00049
    00050       if (skip_left != 0) {
    00051         if (skip_left < trans) {
    00052           trans -= skip_left;
    00053           skip_left = 0;
    00054         } else {
    00055           skip_left -= trans;
    00056           trans = 0;
    00057         }
    00058         if (skip_left < pixels) {
    00059           src += skip_left;
    00060           pixels -= skip_left;
    00061           skip_left = 0;
    00062         } else {
    00063           src += pixels;
    00064           skip_left -= pixels;
    00065           pixels = 0;
    00066         }
    00067       }
    00068       if (skip_left != 0) continue;
    00069
    00070       /* Skip transparent pixels */
    00071       dst += trans;
    00072       width -= trans;
    00073       if (width <= 0 || pixels == 0) continue;
    00074       pixels = min<uint>(pixels, (uint)width);
    00075       width -= pixels;
    00076
    00077       switch (mode) {
    00078         case BM_COLOUR_REMAP: {
    00079           const uint8 *remap = bp->remap;
    00080           do {
    00081             uint m = remap[*src];
    00082             if (m != 0) *dst = m;
    00083             dst++; src++;
    00084           } while (--pixels != 0);
    00085         } break;
    00086
    00087         case BM_TRANSPARENT: {
    00088           const uint8 *remap = bp->remap;
    00089           src += pixels;
    00090           do {
    00091             *dst = remap[*dst];
    00092             dst++;
    00093           } while (--pixels != 0);
    00094         } break;
    00095
    00096         default:
    00097           memcpy(dst, src, pixels);
    00098           dst += pixels; src += pixels;
    00099           break;
    00100       }
    00101     }
    00102   }
    00103 }
    00104
    00105 Sprite *Blitter_8bppOptimized::Encode(SpriteLoader::Sprite *sprite, Blitter::AllocatorProc *allocator)
    00106 {
    00107   /* Make memory for all zoom-levels */
    00108   uint memory = sizeof(SpriteData);
    00109
    00110   for (ZoomLevel i = ZOOM_LVL_BEGIN; i < ZOOM_LVL_END; i++) {
    00111     memory += UnScaleByZoom(sprite->height, i) * UnScaleByZoom(sprite->width, i);
    00112   }
    00113
    00114   /* We have no idea how much memory we really need, so just guess something */
    00115   memory *= 5;
    00116
    00117   /* Don't allocate memory each time, but just keep some
    00118    * memory around as this function is called quite often
    00119    * and the memory usage is quite low. */
    00120   static ReusableBuffer<byte> temp_buffer;
    00121   SpriteData *temp_dst = (SpriteData *)temp_buffer.Allocate(memory);
    00122   byte *dst = temp_dst->data;
    00123
    00124   /* Make the sprites per zoom-level */
    00125   for (ZoomLevel i = ZOOM_LVL_BEGIN; i < ZOOM_LVL_END; i++) {
    00126     /* Store the index table */
    00127     uint offset = dst - temp_dst->data;
    00128     temp_dst->offset[i] = offset;
    00129
    00130     /* cache values, because compiler can't cache it */
    00131     int scaled_height = UnScaleByZoom(sprite->height, i);
    00132     int scaled_width  = UnScaleByZoom(sprite->width,  i);
    00133     int scaled_1      =   ScaleByZoom(1,              i);
    00134
    00135     for (int y = 0; y < scaled_height; y++) {
    00136       uint trans = 0;
    00137       uint pixels = 0;
    00138       uint last_colour = 0;
    00139       byte *count_dst = NULL;
    00140
    00141       /* Store the scaled image */
    00142       const SpriteLoader::CommonPixel *src = &sprite->data[ScaleByZoom(y, i) * sprite->width];
    00143       const SpriteLoader::CommonPixel *src_end = &src[sprite->width];
    00144
    00145       for (int x = 0; x < scaled_width; x++) {
    00146         uint colour = 0;
    00147
    00148         /* Get the colour keeping in mind the zoom-level */
    00149         for (int j = 0; j < scaled_1; j++) {
    00150           if (src->m != 0) colour = src->m;
    00151           /* Because of the scaling it might happen we read outside the buffer. Avoid that. */
    00152           if (++src == src_end) break;
    00153         }
    00154
    00155         if (last_colour == 0 || colour == 0 || pixels == 255) {
    00156           if (count_dst != NULL) {
    00157             /* Write how many non-transparent bytes we get */
    00158             *count_dst = pixels;
    00159             pixels = 0;
    00160             count_dst = NULL;
    00161           }
    00162           /* As long as we find transparency bytes, keep counting */
    00163           if (colour == 0) {
    00164             last_colour = 0;
    00165             trans++;
    00166             continue;
    00167           }
    00168           /* No longer transparency, so write the amount of transparent bytes */
    00169           *dst = trans;
    00170           dst++;
    00171           trans = 0;
    00172           /* Reserve a byte for the pixel counter */
    00173           count_dst = dst;
    00174           dst++;
    00175         }
    00176         last_colour = colour;
    00177         pixels++;
    00178         *dst = colour;
    00179         dst++;
    00180       }
    00181
    00182       if (count_dst != NULL) *count_dst = pixels;
    00183
    00184       /* Write line-ending */
    00185       *dst = 0; dst++;
    00186       *dst = 0; dst++;
    00187     }
    00188   }
    00189
    00190   uint size = dst - (byte *)temp_dst;
    00191
    00192   /* Safety check, to make sure we guessed the size correctly */
    00193   assert(size < memory);
    00194
    00195   /* Allocate the exact amount of memory we need */
    00196   Sprite *dest_sprite = (Sprite *)allocator(sizeof(*dest_sprite) + size);
    00197
    00198   dest_sprite->height = sprite->height;
    00199   dest_sprite->width  = sprite->width;
    00200   dest_sprite->x_offs = sprite->x_offs;
    00201   dest_sprite->y_offs = sprite->y_offs;
    00202   memcpy(dest_sprite->data, temp_dst, size);
    00203
    00204   return dest_sprite;
    00205 }