axmol/cocos2dx/support/image_support/TGAlib.cpp

/****************************************************************************
Copyright (c) 2010 cocos2d-x.org

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****************************************************************************/

#include <string.h>
#include <stdlib.h>

#include "TGAlib.h"
#include "CCFileUtils.h"

namespace cocos2d {

static bool tgaLoadRLEImageData(unsigned char* Buffer, unsigned long bufSize, tImageTGA *psInfo);
void tgaFlipImage( tImageTGA *info );

// load the image header field from stream
bool tgaLoadHeader(unsigned char* Buffer, unsigned long bufSize, tImageTGA *psInfo)
{
    bool bRet = false;

    do 
    {
        size_t step = sizeof(unsigned char) * 2;
        CC_BREAK_IF((step + sizeof(unsigned char)) > bufSize);
        memcpy(&psInfo->type, Buffer + step, sizeof(unsigned char));

        step += sizeof(unsigned char) * 2;
        step += sizeof(signed short) * 4;
        CC_BREAK_IF((step + sizeof(signed short) * 2 + sizeof(unsigned char)) > bufSize);
        memcpy(&psInfo->width, Buffer + step, sizeof(signed short));
        memcpy(&psInfo->height, Buffer + step + sizeof(signed short), sizeof(signed short));
        memcpy(&psInfo->pixelDepth, Buffer + step + sizeof(signed short) * 2, sizeof(unsigned char));

        step += sizeof(unsigned char);
        step += sizeof(signed short) * 2;
        CC_BREAK_IF((step + sizeof(unsigned char)) > bufSize);
        unsigned char cGarbage;
        memcpy(&cGarbage, Buffer + step, sizeof(unsigned char));

        psInfo->flipped = 0;
        if ( cGarbage & 0x20 ) 
        {
            psInfo->flipped = 1;
        }
        bRet = true;
    } while (0);

    return bRet;
}

bool tgaLoadImageData(unsigned char *Buffer, unsigned long bufSize, tImageTGA *psInfo)
{
    bool bRet = false;

    do 
    {
        int mode,total,i;
        unsigned char aux;
        size_t step = (sizeof(unsigned char) + sizeof(signed short)) * 6;

        // mode equal the number of components for each pixel
        mode = psInfo->pixelDepth / 8;
        // total is the number of unsigned chars we'll have to read
        total = psInfo->height * psInfo->width * mode;

        size_t dataSize = sizeof(unsigned char) * total;
        CC_BREAK_IF((step + dataSize) > bufSize);
        memcpy(psInfo->imageData, Buffer + step, dataSize);

        // mode=3 or 4 implies that the image is RGB(A). However TGA
        // stores it as BGR(A) so we'll have to swap R and B.
        if (mode >= 3)
        {
            for (i=0; i < total; i+= mode)
            {
                aux = psInfo->imageData[i];
                psInfo->imageData[i] = psInfo->imageData[i+2];
                psInfo->imageData[i+2] = aux;
            }
        }

        bRet = true;
    } while (0);

    return bRet;
}

static bool tgaLoadRLEImageData(unsigned char* Buffer, unsigned long bufSize, tImageTGA *psInfo)
{
    unsigned int mode,total,i, index = 0;
    unsigned char aux[4], runlength = 0;
    unsigned int skip = 0, flag = 0;
    size_t step = (sizeof(unsigned char) + sizeof(signed short)) * 6;

    // mode equal the number of components for each pixel
    mode = psInfo->pixelDepth / 8;
    // total is the number of unsigned chars we'll have to read
    total = psInfo->height * psInfo->width;

    for( i = 0; i < total; i++ )
    {
        // if we have a run length pending, run it
        if ( runlength != 0 )
        {
            // we do, update the run length count
            runlength--;
            skip = (flag != 0);
        }
        else
        {
            // otherwise, read in the run length token
            CC_BREAK_IF((step + sizeof(unsigned char)) > bufSize);
            memcpy(&runlength, Buffer + step, sizeof(unsigned char));
            step += sizeof(unsigned char);

            // see if it's a RLE encoded sequence
            flag = runlength & 0x80;
            if ( flag )
            {
                runlength -= 128;
            }
            skip = 0;
        }

        // do we need to skip reading this pixel?
        if ( !skip )
        {
            // no, read in the pixel data
            CC_BREAK_IF((step + sizeof(unsigned char) * mode) > bufSize);

            memcpy(aux, Buffer + step, sizeof(unsigned char) * mode);
            step += sizeof(unsigned char) * mode;

            // mode=3 or 4 implies that the image is RGB(A). However TGA
            // stores it as BGR(A) so we'll have to swap R and B.
            if ( mode >= 3 )
            {
                unsigned char tmp;

                tmp = aux[0];
                aux[0] = aux[2];
                aux[2] = tmp;
            }
        }

        // add the pixel to our image
        memcpy(&psInfo->imageData[index], aux, mode);
        index += mode;
    }
    
    return true;
}

void tgaFlipImage( tImageTGA *psInfo )
{
    // mode equal the number of components for each pixel
    int mode = psInfo->pixelDepth / 8;
    int rowbytes = psInfo->width*mode;
    unsigned char *row = (unsigned char *)malloc(rowbytes);
    int y;
    
    if (row == NULL) return;
    
    for( y = 0; y < (psInfo->height/2); y++ )
    {
        memcpy(row, &psInfo->imageData[y*rowbytes],rowbytes);
        memcpy(&psInfo->imageData[y*rowbytes], &psInfo->imageData[(psInfo->height-(y+1))*rowbytes], rowbytes);
        memcpy(&psInfo->imageData[(psInfo->height-(y+1))*rowbytes], row, rowbytes);
    }
    
    free(row);
    psInfo->flipped = 0;
}

// this is the function to call when we want to load an image
tImageTGA * tgaLoad(const char *pszFilename)
{
    int mode,total;
    tImageTGA *info = NULL;
    
    unsigned long nSize;
    unsigned char *pBuffer = CCFileUtils::sharedFileUtils()->getFileData(pszFilename, "rb", &nSize);

    do
    {
        CC_BREAK_IF(! pBuffer);
        info = (tImageTGA *)malloc(sizeof(tImageTGA));

        // get the file header info
        if (! tgaLoadHeader(pBuffer, nSize, info))
        {
            info->status = TGA_ERROR_MEMORY;
            break;
        }

        // check if the image is color indexed
        if (info->type == 1)
        {
            info->status = TGA_ERROR_INDEXED_COLOR;
            break;
        }

        // check for other types (compressed images)
        if ((info->type != 2) && (info->type !=3) && (info->type !=10) )
        {
            info->status = TGA_ERROR_COMPRESSED_FILE;
            break;
        }

        // mode equals the number of image components
        mode = info->pixelDepth / 8;
        // total is the number of unsigned chars to read
        total = info->height * info->width * mode;
        // allocate memory for image pixels
        info->imageData = (unsigned char *)malloc(sizeof(unsigned char) * total);

        // check to make sure we have the memory required
        if (info->imageData == NULL)
        {
            info->status = TGA_ERROR_MEMORY;
            break;
        }

        bool bLoadImage = false;
        // finally load the image pixels
        if ( info->type == 10 )
        {
            bLoadImage = tgaLoadRLEImageData(pBuffer, nSize, info);
        }
        else
        {
            bLoadImage = tgaLoadImageData(pBuffer, nSize, info);
        }

        // check for errors when reading the pixels
        if (! bLoadImage)
        {
            info->status = TGA_ERROR_READING_FILE;
            break;
        }
        info->status = TGA_OK;

        if ( info->flipped )
        {
            tgaFlipImage( info );
            if ( info->flipped )
            {
                info->status = TGA_ERROR_MEMORY;
            }
        }
    } while(0);

    return info;
}

// converts RGB to greyscale
void tgaRGBtogreyscale(tImageTGA *psInfo) {
    
    int mode,i,j;
    
    unsigned char *newImageData;
    
    // if the image is already greyscale do nothing
    if (psInfo->pixelDepth == 8)
        return;
    
    // compute the number of actual components
    mode = psInfo->pixelDepth / 8;
    
    // allocate an array for the new image data
    newImageData = (unsigned char *)malloc(sizeof(unsigned char) * 
                                           psInfo->height * psInfo->width);
    if (newImageData == NULL) {
        return;
    }
    
    // convert pixels: greyscale = o.30 * R + 0.59 * G + 0.11 * B
    for (i = 0,j = 0; j < psInfo->width * psInfo->height; i +=mode, j++)
        newImageData[j] =    
        (unsigned char)(0.30 * psInfo->imageData[i] + 
                        0.59 * psInfo->imageData[i+1] +
                        0.11 * psInfo->imageData[i+2]);
    
    
    //free old image data
    free(psInfo->imageData);
    
    // reassign pixelDepth and type according to the new image type
    psInfo->pixelDepth = 8;
    psInfo->type = 3;
    // reassing imageData to the new array.
    psInfo->imageData = newImageData;
}

// releases the memory used for the image
void tgaDestroy(tImageTGA *psInfo) {
    
    if (psInfo != NULL) {
        if (psInfo->imageData != NULL)
        {
            free(psInfo->imageData);
        }

        free(psInfo);
    }
}
}//namespace   cocos2d