学步园

tga 文件头信息如下图:

代码如下：

#ifndef __XETGA_H__<br /> #define __XETGA_H__ </p> <p>#include "XEPrerequisites.h"</p> <p>namespace XE<br /> {</p> <p>struct TGA_HEADER<br /> {<br /> unsigned short _width; ///<tga宽度<br /> unsigned short _height; ///<tga高度<br /> unsigned char _bitsPerPixel; ///<tga像素位数<br /> unsigned char _describe; ///<tga描述字节<br /> };</p> <p>class _XEExport TGA<br /> {<br /> public: </p> <p> TGA();<br /> ~TGA(); </p> <p> bool load(const std::string& fileName);<br /> bool load(unsigned char* data);<br /> bool getPixel(unsigned int index, unsigned char& red, unsigned char& green, unsigned char& blue, unsigned char& alpha) const;<br /> bool setPixel(unsigned int index, unsigned char red, unsigned char green, unsigned char blue, unsigned char alpha);<br /> bool save(const std::string& fileName);<br /> bool saveRect(const std::string& fileName, const Rect& rect);</p> <p> ///设置头信息<br /> void setHeader(const TGA_HEADER& header) { m_header = header; }<br /> ///获得头信息<br /> const TGA_HEADER& getHeader() { return m_header; }</p> <p> ///设置数据块<br /> void setData(unsigned char * data) { if( m_data )free(m_data); m_data = data; }<br /> ///获得数据块<br /> unsigned char * getData() { return m_data; }</p> <p> ///设置数据块大小<br /> void setDataSize(unsigned int dataSize) { m_dataSize = dataSize; }<br /> ///获得数据块大小<br /> unsigned int getDataSize() { return m_dataSize; }</p> <p> ///设置像素字节大小<br /> void setBytesPerPixel(unsigned int bytesPerPixe) { m_bytesPerPixel = bytesPerPixe; }<br /> ///获得像素字节大小<br /> unsigned int getBytesPerPixel() { return m_bytesPerPixel; }</p> <p>private:</p> <p> bool _loadUncompressedTGA(FILE *);<br /> bool _loadCompressedTGA(FILE *);<br /> bool _loadUncompressedTGA(unsigned char* data);<br /> bool _loadCompressedTGA(unsigned char* data);</p> <p>private:</p> <p> TGA_HEADER m_header; ///< 头信息<br /> unsigned char * m_data; ///< 数据块<br /> unsigned int m_dataSize; ///< 数据块大小<br /> unsigned int m_bytesPerPixel; ///< 像素字节大小<br /> }; </p> <p>}//XE</p> <p>#endif __XETGA_H__<br />

#include "XEStableHeaders.h"<br /> #include "XETga.h"<br /> #include "XERect.h"</p> <p>namespace XE<br /> {</p> <p>TGA::TGA()<br /> {<br /> m_data = 0;<br /> }</p> <p>TGA::~TGA()<br /> {<br /> if( m_data )<br /> {<br /> free(m_data);<br /> m_data = 0;<br /> }<br /> }</p> <p>bool TGA::load(const std::string& fileName)<br /> {<br /> FILE * __file = fopen(fileName.c_str(),"rb");<br /> if(__file == NULL)<br /> {<br /> return false;<br /> }</p> <p> unsigned char __header[12];<br /> if(fread(&__header, sizeof(__header), 1, __file) == 0)<br /> {<br /> fclose(__file);<br /> return false;<br /> }</p> <p> //未压缩TGA文件头<br /> unsigned char uTGAcompare[12] = {0,0,2, 0,0,0,0,0,0,0,0,0};<br /> //压缩TGA文件头<br /> unsigned char cTGAcompare[12] = {0,0,10,0,0,0,0,0,0,0,0,0};</p> <p> if(memcmp(uTGAcompare, &__header, sizeof(__header)) == 0)<br /> {<br /> return _loadUncompressedTGA(__file);<br /> }<br /> else if(memcmp(cTGAcompare, &__header, sizeof(__header)) == 0)<br /> {<br /> return _loadCompressedTGA(__file);<br /> }<br /> else<br /> {<br /> fclose(__file);<br /> return false;<br /> }<br /> }</p> <p>bool TGA::load(unsigned char* data)<br /> {<br /> unsigned char __header[12];<br /> memcpy(__header, data, 12);</p> <p> //未压缩TGA文件头<br /> unsigned char uTGAcompare[12] = {0,0,2, 0,0,0,0,0,0,0,0,0};<br /> //压缩TGA文件头<br /> unsigned char cTGAcompare[12] = {0,0,10,0,0,0,0,0,0,0,0,0};</p> <p> if(memcmp(uTGAcompare, &__header, sizeof(__header)) == 0)<br /> {<br /> return _loadUncompressedTGA(data);<br /> }<br /> else if(memcmp(cTGAcompare, &__header, sizeof(__header)) == 0)<br /> {<br /> return _loadCompressedTGA(data);<br /> }</p> <p> return false;<br /> }</p> <p>bool TGA::_loadUncompressedTGA(unsigned char* data)<br /> {<br /> //unsigned char _header[6];<br /> //memcpy(_header, data + 12, 6);<br /> //<br /> //m_width = _header[1] * 256 + _header[0]; // Determine The TGA Width (highbyte*256+lowbyte)<br /> //m_height = _header[3] * 256 + _header[2]; // Determine The TGA Height (highbyte*256+lowbyte)<br /> //m_bitsPerPixel = _header[4]; // Determine the bits per pixel</p> <p> memcpy(&m_header, data + 12, sizeof(m_header));<br /> if((m_header._bitsPerPixel != 24) && (m_header._bitsPerPixel !=32))<br /> {<br /> return false;<br /> }</p> <p> m_bytesPerPixel = (m_header._bitsPerPixel / 8); // Compute the number of BYTES per pixel<br /> m_dataSize = (m_bytesPerPixel * m_header._width * m_header._height); // Compute the total amout ofmemory needed to store data<br /> m_data = (unsigned char*)malloc(m_dataSize); // Allocate that much memory</p> <p> if(m_data == NULL)<br /> {<br /> return false;<br /> }</p> <p> memcpy(m_data, data + 18, m_dataSize);</p> <p> //// Byte Swapping Optimized By Steve Thomas<br /> //for(unsigned int cswap = 0; cswap < m_dataSize; cswap += m_bytesPerPixel)<br /> //{<br /> // m_data[cswap] ^= m_data[cswap+2] ^=<br /> // m_data[cswap] ^= m_data[cswap+2];<br /> //}</p> <p> return true;<br /> }</p> <p>bool TGA::_loadUncompressedTGA(FILE * file)<br /> {<br /> //unsigned char _header[6];<br /> //if(fread(_header, sizeof(_header), 1, file) == 0)<br /> //{<br /> // fclose(file);<br /> // return false;<br /> //} </p> <p> //m_width = _header[1] * 256 + _header[0]; // Determine The TGA Width (highbyte*256+lowbyte)<br /> //m_height = _header[3] * 256 + _header[2]; // Determine The TGA Height (highbyte*256+lowbyte)<br /> //m_bitsPerPixel = _header[4]; // Determine the bits per pixel</p> <p> if(fread(&m_header, sizeof(m_header), 1, file) == 0)<br /> {<br /> fclose(file);<br /> return false;<br /> } </p> <p> if((m_header._bitsPerPixel != 24) && (m_header._bitsPerPixel !=32))<br /> {<br /> fclose(file);<br /> return false;<br /> }</p> <p> m_bytesPerPixel = (m_header._bitsPerPixel / 8); // Compute the number of BYTES per pixel<br /> m_dataSize = (m_bytesPerPixel * m_header._width * m_header._height); // Compute the total amout ofmemory needed to store data<br /> m_data = (unsigned char*)malloc(m_dataSize); // Allocate that much memory</p> <p> if(m_data == NULL)<br /> {<br /> fclose(file);<br /> return false;<br /> }</p> <p> if(fread(m_data, 1, m_dataSize, file) != m_dataSize) // Attempt to read image data<br /> {<br /> free(m_data);<br /> fclose(file);<br /> return false;<br /> }</p> <p> // Byte Swapping Optimized By Steve Thomas<br /> /*for(unsigned int cswap = 0; cswap < m_dataSize; cswap += m_bytesPerPixel)<br /> {<br /> m_data[cswap] ^= m_data[cswap+2] ^=<br /> m_data[cswap] ^= m_data[cswap+2];<br /> }*/</p> <p> fclose(file);<br /> return true;<br /> }</p> <p>bool TGA::save(const std::string& fileName)<br /> {<br /> FILE* __file = fopen(fileName.c_str(),"wb+");<br /> if(__file == NULL)<br /> {<br /> return false;<br /> }</p> <p> if(m_data == NULL)<br /> {<br /> return false;<br /> }</p> <p> unsigned char uTGAcompare[12] = {0,0,2, 0,0,0,0,0,0,0,0,0};</p> <p> fseek(__file,0,SEEK_SET);<br /> fwrite(uTGAcompare, sizeof(uTGAcompare), 1, __file);<br /> fwrite(&m_header._width, sizeof(m_header._width), 1, __file);<br /> fwrite(&m_header._height, sizeof(m_header._height), 1, __file);<br /> fwrite(&m_header._bitsPerPixel, sizeof(m_header._bitsPerPixel), 1, __file);<br /> fwrite(&m_header._describe, sizeof(m_header._describe), 1, __file);</p> <p> unsigned char* __buffer = (unsigned char*) malloc(m_dataSize);<br /> unsigned char* __buffer_temp = __buffer;<br /> size_t __write_buffer_size = 0;<br /> if (__buffer == NULL)<br /> {<br /> fclose(__file);<br /> return false;<br /> } </p> <p> for ( int __row = 0; __row < m_header._height; __row++ )<br /> {<br /> unsigned char* __pixel_buffer = m_data + __row * m_header._width * 4; </p> <p> for ( int __column = 0; __column < m_header._width; __column++ )<br /> {<br /> switch ( m_header._bitsPerPixel )<br /> {<br /> case 24:<br /> {<br /> unsigned char __red = *__pixel_buffer++;<br /> unsigned char __green = *__pixel_buffer++;<br /> unsigned char __blue = *__pixel_buffer++;<br /> unsigned char __alpha = *__pixel_buffer++;</p> <p> *__buffer_temp++ = __blue;<br /> *__buffer_temp++ = __green;<br /> *__buffer_temp++ = __red;<br /> __alpha;</p> <p> __write_buffer_size+=3;<br /> }<br /> break;<br /> case 32:<br /> {<br /> unsigned char __red = *__pixel_buffer++;<br /> unsigned char __green = *__pixel_buffer++;<br /> unsigned char __blue = *__pixel_buffer++;<br /> unsigned char __alpha = *__pixel_buffer++;</p> <p> *__buffer_temp++ = __blue;<br /> *__buffer_temp++ = __green;<br /> *__buffer_temp++ = __red;<br /> *__buffer_temp++ = __alpha;</p> <p> __write_buffer_size+=4;<br /> }<br /> break;<br /> default:<br /> return false;<br /> }<br /> }<br /> }</p> <p> size_t __write_file_size = fwrite( __buffer, 1, __write_buffer_size, __file);<br /> assert( __write_file_size == __write_buffer_size );<br /> if( __write_file_size != __write_buffer_size )<br /> {<br /> free(__buffer);<br /> fclose(__file);<br /> return false;<br /> }</p> <p> free(__buffer);<br /> fclose(__file);<br /> return true;<br /> }</p> <p>bool TGA::saveRect(const std::string& fileName, const Rect& rect)<br /> {<br /> FILE* __file = fopen(fileName.c_str(),"wb+");<br /> if(__file == NULL)<br /> {<br /> return false;<br /> }</p> <p> if(m_data == NULL)<br /> {<br /> return false;<br /> }</p> <p> unsigned char uTGAcompare[12] = {0,0,2, 0,0,0,0,0,0,0,0,0};</p> <p> Rect _rect(rect);<br /> if( _rect.top < 0.0f )<br /> _rect.top = 0.0f;<br /> if( _rect.left < 0.0f )<br /> _rect.left = 0.0f;<br /> if( _rect.bottom > m_header._height )<br /> _rect.bottom = m_header._height;<br /> if( _rect.right > m_header._width )<br /> _rect.right = m_header._width;</p> <p> unsigned short _width = _rect.right - _rect.left;<br /> unsigned short _height = _rect.bottom - _rect.top;</p> <p> fseek(__file,0,SEEK_SET);<br /> fwrite(uTGAcompare, sizeof(uTGAcompare), 1, __file);<br /> fwrite(&_width, sizeof(_width), 1, __file);<br /> fwrite(&_height, sizeof(_height), 1, __file);<br /> fwrite(&m_header._bitsPerPixel, sizeof(m_header._bitsPerPixel), 1, __file);<br /> fwrite(&m_header._describe, sizeof(m_header._describe), 1, __file);</p> <p> unsigned int _dataSize = _width * _height * m_bytesPerPixel;<br /> unsigned char* __buffer = (unsigned char*) malloc(_dataSize);<br /> unsigned char* __buffer_temp = __buffer;<br /> size_t __write_buffer_size = 0;<br /> if (__buffer == NULL)<br /> {<br /> fclose(__file);<br /> return false;<br /> } </p> <p> for ( int __row = _rect.top; __row < _rect.bottom; __row++ )<br /> {<br /> unsigned char* __pixel_buffer = m_data + __row * m_header._width * 4 + (int)_rect.left * 4; </p> <p> for ( int __column = _rect.left; __column < _rect.right; __column++ )<br /> {<br /> switch ( m_header._bitsPerPixel )<br /> {<br /> case 24:<br /> {<br /> unsigned char __red = *__pixel_buffer++;<br /> unsigned char __green = *__pixel_buffer++;<br /> unsigned char __blue = *__pixel_buffer++;<br /> unsigned char __alpha = *__pixel_buffer++;</p> <p> *__buffer_temp++ = __blue;<br /> *__buffer_temp++ = __green;<br /> *__buffer_temp++ = __red;<br /> __alpha;</p> <p> __write_buffer_size+=3;<br /> }<br /> break;<br /> case 32:<br /> {<br /> unsigned char __red = *__pixel_buffer++;<br /> unsigned char __green = *__pixel_buffer++;<br /> unsigned char __blue = *__pixel_buffer++;<br /> unsigned char __alpha = *__pixel_buffer++;</p> <p> *__buffer_temp++ = __blue;<br /> *__buffer_temp++ = __green;<br /> *__buffer_temp++ = __red;<br /> *__buffer_temp++ = __alpha;</p> <p> __write_buffer_size+=4;<br /> }<br /> break;<br /> default:<br /> return false;<br /> }<br /> }<br /> }</p> <p> size_t __write_file_size = fwrite( __buffer, 1, __write_buffer_size, __file);<br /> assert( __write_file_size == __write_buffer_size );<br /> if( __write_file_size != __write_buffer_size )<br /> {<br /> free(__buffer);<br /> fclose(__file);<br /> return false;<br /> }</p> <p> free(__buffer);<br /> fclose(__file);<br /> return true;<br /> }</p> <p>bool TGA::_loadCompressedTGA(unsigned char* data)<br /> {<br /> return false;<br /> }</p> <p>bool TGA::getPixel(unsigned int index, unsigned char& red, unsigned char& green, unsigned char& blue, unsigned char& alpha) const<br /> {<br /> if( index < 0 || index > m_dataSize )<br /> return false;</p> <p> unsigned char* __data = m_data + index * m_bytesPerPixel;<br /> switch ( m_header._bitsPerPixel )<br /> {<br /> case 24:<br /> {<br /> red = *__data++;<br /> green = *__data++;<br /> blue = *__data++;<br /> alpha;<br /> }<br /> break;<br /> case 32:<br /> {<br /> red = *__data++;<br /> green = *__data++;<br /> blue = *__data++;<br /> alpha = *__data++;;<br /> }<br /> break;<br /> default:<br /> return false;<br /> }</p> <p> return true;<br /> }</p> <p>bool TGA::setPixel(unsigned int index, unsigned char red, unsigned char green, unsigned char blue, unsigned char alpha)<br /> {<br /> if( index < 0 || index > m_dataSize )<br /> return false;</p> <p> unsigned char* __data = m_data + index * m_bytesPerPixel;<br /> switch ( m_header._bitsPerPixel )<br /> {<br /> case 24:<br /> {<br /> *__data++ = red;<br /> *__data++ = green;<br /> *__data++ = blue;<br /> alpha;<br /> }<br /> break;<br /> case 32:<br /> {<br /> *__data++ = red;<br /> *__data++ = green;<br /> *__data++ = blue;<br /> *__data++ = alpha;<br /> }<br /> break;<br /> default:<br /> return false;<br /> }</p> <p> return true;<br /> }</p> <p>bool TGA::_loadCompressedTGA(FILE * file)<br /> {<br /> //unsigned char _header[6];<br /> //if(fread(_header, sizeof(_header), 1, file) == 0)<br /> //{<br /> // fclose(file);<br /> // return false;<br /> //}</p> <p> //m_width = _header[1] * 256 + _header[0]; // Determine The TGA Width (highbyte*256+lowbyte)<br /> //m_height = _header[3] * 256 + _header[2]; // Determine The TGA Height (highbyte*256+lowbyte)<br /> //m_bitsPerPixel = _header[4]; // Determine the bits per pixel</p> <p> if(fread(&m_header, sizeof(m_header), 1, file) == 0)<br /> {<br /> fclose(file);<br /> return false;<br /> } </p> <p> if((m_header._bitsPerPixel != 24) && (m_header._bitsPerPixel !=32))<br /> {<br /> fclose(file);<br /> return false;<br /> }</p> <p> m_bytesPerPixel = (m_header._bitsPerPixel / 8); // Compute BYTES per pixel<br /> m_dataSize = (m_bytesPerPixel * m_header._width * m_header._height); // Compute amout of memory needed to store image<br /> m_data = (unsigned char *)malloc(m_dataSize); // Allocate that much memory</p> <p> if(m_data == NULL)<br /> {<br /> fclose(file);<br /> return false;<br /> }</p> <p> unsigned int pixelcount = m_header._width * m_header._height; // Nuber of pixels in the image<br /> unsigned int currentpixel = 0; // Current pixel being read<br /> unsigned int currentbyte = 0; // Current byte<br /> unsigned char * colorbuffer = (unsigned char *)malloc(m_bytesPerPixel); // Storage for 1 pixel</p> <p> do<br /> {<br /> unsigned char chunkheader = 0;<br /> if(fread(&chunkheader, sizeof(unsigned char), 1, file) == 0) // Read in the 1 byte header<br /> {<br /> fclose(file);<br /> free(m_data);<br /> return false; // Return failed<br /> }</p> <p> if(chunkheader < 128) // If the ehader is < 128, it means the that is the number of RAW color packets minus 1<br /> { // that follow the header<br /> chunkheader++; // add 1 to get number of following color values<br /> for(short counter = 0; counter < chunkheader; counter++) // Read RAW color values<br /> {<br /> if(fread(colorbuffer, 1, m_bytesPerPixel, file) != m_bytesPerPixel) // Try to read 1 pixel<br /> {<br /> fclose(file);<br /> free(colorbuffer);<br /> free(m_data);<br /> return false; // Return failed<br /> }<br /> // write to memory<br /> m_data[currentbyte ] = colorbuffer[2]; // Flip R and B vcolor values around in the process<br /> m_data[currentbyte + 1 ] = colorbuffer[1];<br /> m_data[currentbyte + 2 ] = colorbuffer[0];</p> <p> if(m_bytesPerPixel == 4) // if its a 32 bpp image<br /> {<br /> m_data[currentbyte + 3] = colorbuffer[3]; // copy the 4th byte<br /> }</p> <p> currentbyte += m_bytesPerPixel; // Increase thecurrent byte by the number of bytes per pixel<br /> currentpixel++; // Increase current pixel by 1</p> <p> if(currentpixel > pixelcount) // Make sure we havent read too many pixels<br /> {<br /> fclose(file);<br /> free(colorbuffer);<br /> free(m_data);<br /> return false; // Return failed<br /> }<br /> }<br /> }<br /> else // chunkheader > 128 RLE data, next color reapeated chunkheader - 127 times<br /> {<br /> chunkheader -= 127; // Subteact 127 to get rid of the ID bit<br /> if(fread(colorbuffer, 1, m_bytesPerPixel, file) != m_bytesPerPixel) // Attempt to read following color values<br /> {<br /> fclose(file);<br /> free(colorbuffer);<br /> free(m_data);<br /> return false;<br /> }</p> <p> for(short counter = 0; counter < chunkheader; counter++) // copy the color into the image data as many times as dictated<br /> { // by the header<br /> m_data[currentbyte ] = colorbuffer[2]; // switch R and B bytes areound while copying<br /> m_data[currentbyte + 1 ] = colorbuffer[1];<br /> m_data[currentbyte + 2 ] = colorbuffer[0];</p> <p> if(m_bytesPerPixel == 4) // If TGA images is 32 bpp<br /> {<br /> m_data[currentbyte + 3] = colorbuffer[3]; // Copy 4th byte<br /> }</p> <p> currentbyte += m_bytesPerPixel; // Increase current byte by the number of bytes per pixel<br /> currentpixel++; // Increase pixel count by 1</p> <p> if(currentpixel > pixelcount) // Make sure we havent written too many pixels<br /> {<br /> fclose(file);<br /> free(colorbuffer);<br /> free(m_data);<br /> return false; // Return failed<br /> }<br /> }<br /> }<br /> }<br /> while(currentpixel < pixelcount); // Loop while there are still pixels left</p> <p> fclose(file); // Close the file<br /> return true; // return success<br /> }</p> <p>} //XE<br />