011
08.01.2005, 13:45 Uhr
FloSoft
Medialer Over-Flow
(Administrator)
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NEHE Tutorial Lesson 25: Loading Compressed And Uncompressed TGA's
| C++: |
bool LoadTGA(TextureImage *texture, char *filename) // Loads A TGA File Into Memory
{
GLubyte TGAheader[12]={0,0,2,0,0,0,0,0,0,0,0,0}; // Uncompressed TGA Header
GLubyte TGAcompare[12]; // Used To Compare TGA Header
GLubyte header[6]; // First 6 Useful Bytes From The Header
GLuint bytesPerPixel; // Holds Number Of Bytes Per Pixel Used In The TGA File
GLuint imageSize; // Used To Store The Image Size When Setting Aside Ram
GLuint temp; // Temporary Variable
GLuint type=GL_RGBA; // Set The Default GL Mode To RBGA (32 BPP)
FILE *file = fopen(filename, "rb"); // Open The TGA File
if( file==NULL || // Does File Even Exist?
fread(TGAcompare,1,sizeof(TGAcompare),file)!=sizeof(TGAcompare) || // Are There 12 Bytes To Read?
memcmp(TGAheader,TGAcompare,sizeof(TGAheader))!=0 || // Does The Header Match What We Want?
fread(header,1,sizeof(header),file)!=sizeof(header)) // If So Read Next 6 Header Bytes
{
fclose(file); // If Anything Failed, Close The File
return false; // Return False
}
texture->width = header[1] * 256 + header[0]; // Determine The TGA Width (highbyte*256+lowbyte)
texture->height = header[3] * 256 + header[2]; // Determine The TGA Height (highbyte*256+lowbyte)
if( texture->width <=0 || // Is The Width Less Than Or Equal To Zero
texture->height <=0 || // Is The Height Less Than Or Equal To Zero
(header[4]!=24 && header[4]!=32)) // Is The TGA 24 or 32 Bit?
{
fclose(file); // If Anything Failed, Close The File
return false; // Return False
}
texture->bpp = header[4]; // Grab The TGA's Bits Per Pixel (24 or 32)
bytesPerPixel = texture->bpp/8; // Divide By 8 To Get The Bytes Per Pixel
imageSize = texture->width*texture->height*bytesPerPixel; // Calculate The Memory Required For The TGA Data
texture->imageData=(GLubyte *)malloc(imageSize); // Reserve Memory To Hold The TGA Data
if( texture->imageData==NULL || // Does The Storage Memory Exist?
fread(texture->imageData, 1, imageSize, file)!=imageSize) // Does The Image Size Match The Memory Reserved?
{
if(texture->imageData!=NULL) // Was Image Data Loaded
free(texture->imageData); // If So, Release The Image Data
fclose(file); // Close The File
return false; // Return False
}
for(GLuint i=0; iimageData[i]; // Temporarily Store The Value At Image Data 'i'
texture->imageData[i] = texture->imageData[i + 2]; // Set The 1st Byte To The Value Of The 3rd Byte
texture->imageData[i + 2] = temp; // Set The 3rd Byte To The Value In 'temp' (1st Byte Value)
}
fclose (file); // Close The File
// Build A Texture From The Data
glGenTextures(1, &texture[0].texID); // Generate OpenGL texture IDs
glBindTexture(GL_TEXTURE_2D, texture[0].texID); // Bind Our Texture
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); // Linear Filtered
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Linear Filtered
if (texture[0].bpp==24) // Was The TGA 24 Bits
{
type=GL_RGB; // If So Set The 'type' To GL_RGB
}
glTexImage2D(GL_TEXTURE_2D, 0, type, texture[0].width, texture[0].height, 0, type, GL_UNSIGNED_BYTE, texture[0].imageData);
return true; // Texture Building Went Ok, Return True
}
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--
class God : public ChuckNorris { };
Dieser Post wurde am 08.01.2005 um 13:46 Uhr von FloSoft editiert. |
