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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "GLcommon/PaletteTexture.h"
#include <stdio.h>
struct Color
{
Color(unsigned char r, unsigned char g,unsigned char b, unsigned char a):red(r),green(g),blue(b),alpha(a){};
unsigned char red;
unsigned char green;
unsigned char blue;
unsigned char alpha;
};
void getPaletteInfo(GLenum internalFormat,unsigned int& indexSizeBits,unsigned int& colorSizeBytes,GLenum& colorFrmt) {
colorFrmt = GL_RGB;
switch(internalFormat)
{
case GL_PALETTE4_RGB8_OES:
indexSizeBits = 4;
colorSizeBytes = 3;
break;
case GL_PALETTE4_RGBA8_OES:
indexSizeBits = 4;
colorSizeBytes = 4;
colorFrmt = GL_RGBA;
break;
case GL_PALETTE4_RGBA4_OES:
case GL_PALETTE4_RGB5_A1_OES:
colorFrmt = GL_RGBA;
/* fall-through */
case GL_PALETTE4_R5_G6_B5_OES:
indexSizeBits = 4;
colorSizeBytes = 2;
break;
case GL_PALETTE8_RGB8_OES:
indexSizeBits = 8;
colorSizeBytes = 3;
break;
case GL_PALETTE8_RGBA8_OES:
indexSizeBits = 8;
colorSizeBytes = 4;
colorFrmt = GL_RGBA;
break;
case GL_PALETTE8_RGBA4_OES:
case GL_PALETTE8_RGB5_A1_OES:
colorFrmt = GL_RGBA;
/* fall-through */
case GL_PALETTE8_R5_G6_B5_OES:
indexSizeBits = 8;
colorSizeBytes = 2;
break;
}
}
Color paletteColor(const unsigned char* pallete,unsigned int index,GLenum format)
{
short s;
switch(format) {
//RGB
case GL_PALETTE4_RGB8_OES:
case GL_PALETTE8_RGB8_OES:
return Color(pallete[index],pallete[index+1],pallete[index+2],0);
case GL_PALETTE8_R5_G6_B5_OES:
case GL_PALETTE4_R5_G6_B5_OES:
s = *((short *)(pallete+index));
return Color((s >> 11)*255/31,((s >> 5) & 0x3f)*255/63 ,(s & 0x1f)*255/31,0);
//RGBA
case GL_PALETTE4_RGBA8_OES:
case GL_PALETTE8_RGBA8_OES:
return Color(pallete[index],pallete[index+1],pallete[index+2],pallete[index+3]);
case GL_PALETTE4_RGBA4_OES:
case GL_PALETTE8_RGBA4_OES:
s = *((short *)(pallete+index));
return Color(((s >> 12) & 0xf)*255/15,((s >> 8) & 0xf)*255/15,((s >> 4) & 0xf)*255/15 ,(s & 0xf)*255/15);
case GL_PALETTE4_RGB5_A1_OES:
case GL_PALETTE8_RGB5_A1_OES:
s = *((short *)(pallete+index));
return Color(((s >> 11) & 0x1f)*255/31,((s >> 6) & 0x1f)*255/31,((s >> 1) & 0x1f)*255/31 ,(s & 0x1) * 255);
default:
return Color(255,255,255,255);
}
}
unsigned char* uncompressTexture(GLenum internalformat,GLenum& formatOut,GLsizei width,GLsizei height,GLsizei imageSize, const GLvoid* data,GLint level) {
unsigned int indexSizeBits; //the size of the color index in the pallete
unsigned int colorSizeBytes; //the size of each color cell in the pallete
getPaletteInfo(internalformat,indexSizeBits,colorSizeBytes,formatOut);
if(!data)
{
return NULL;
}
const unsigned char* palette = static_cast<const unsigned char *>(data);
//the pallete positioned in the begininng of the data
// so we jump over it to get to the colos indices in the palette
int nColors = 2 << (indexSizeBits -1); //2^indexSizeBits
int paletteSizeBytes = nColors*colorSizeBytes;
const unsigned char* imageIndices = palette + paletteSizeBytes;
//jumping to the the correct mipmap level
for(int i=0;i<level;i++) {
imageIndices+= (width*height*indexSizeBits)/8;
width = width >> 1;
height = height >> 1;
}
int colorSizeOut = (formatOut == GL_RGB? 3:4);
int nPixels = width*height;
unsigned char* pixelsOut = new unsigned char[nPixels*colorSizeOut];
if(!pixelsOut) return NULL;
int leftBytes = ((palette + imageSize) /* the end of data pointer*/
- imageIndices);
int leftPixels = (leftBytes * 8 )/indexSizeBits;
int maxIndices = (leftPixels < nPixels) ? leftPixels:nPixels;
//filling the pixels array
for(int i =0 ; i < maxIndices ; i++) {
int paletteIndex = 0;
int indexOut = i*colorSizeOut;
if(indexSizeBits == 4) {
paletteIndex = (i%2) == 0 ?
imageIndices[i/2] >> 4: //upper bits
imageIndices[i/2] & 0xf; //lower bits
} else {
paletteIndex = imageIndices[i];
}
paletteIndex*=colorSizeBytes;
Color c = paletteColor(palette,paletteIndex,internalformat);
pixelsOut[indexOut] = c.red;
pixelsOut[indexOut+1] = c.green;
pixelsOut[indexOut+2] = c.blue;
if(formatOut == GL_RGBA) {
pixelsOut[indexOut+3] = c.alpha;
}
}
return pixelsOut;
}
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