I've replaced TGA loader in my game with libpng 1.2.37 as i think PNG is much better format and soon i've found problem with code. I have copied code from here http://en.wikibooks....ediate/Textures , included all libs and headers in project and succesfully compiled the code without any errors and warnings but now my game seems to crash at:
[source lang="cpp"] // read all the info up to the image data
png_read_info(png_ptr, info_ptr);[/source]
I though that invalid PNG file was causing the problem so i tried to load pngs included with libpng but it didnt work either.
Does anybody know how to fix that issue? Any help appericated
I'm attaching code here:
[source lang="cpp"] MaterialDef mtl = createMaterial( fileName, fileName, 0, 0, 0, 0, 0 );
mtl.num = loadImage( fileName, mtl.width, mtl.height );
[...........]
#define TEXTURE_LOAD_ERROR 0 //default texture ID
GLuint MaterialManager::loadImage( char fileName[128], int &width, int &height )
{
//http://en.wikibooks.org/wiki/OpenGL_Programming/Intermediate/Textures
//header for testing if it is a png
png_byte header[8];
//open file as binary
FILE *fp = fopen( fileName, "rb" );
if (!fp)
{
Com.warning( "loadImage: failed to open %s", fileName );
return TEXTURE_LOAD_ERROR;
}
//read the header
fread(header, 1, 8, fp);
//test if png
int is_png = !png_sig_cmp(header, 0, 8);
if (!is_png)
{
Com.warning( "loadImage: %s is not an PNG", fileName );
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//create png struct
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
{
Com.warning( "loadImage: png_create_read_struct failed for %", fileName );
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//create png info struct
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
Com.warning( "loadImage: png_create_info_struct(info_ptr) failed for %", fileName );
png_destroy_read_struct(&png_ptr, (png_infopp) NULL, (png_infopp) NULL);
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//create png info struct
png_infop end_info = png_create_info_struct(png_ptr);
if (!end_info)
{
Com.warning( "loadImage: png_create_info_struct(end_info) failed for %", fileName );
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//png error stuff, not sure libpng man suggests this.
if( setjmp(png_jmpbuf(png_ptr)) )
{
Com.warning( "loadImage: setjmp(png_jmpbuf(png_ptr)) caused by %", fileName );
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//init png reading
png_init_io(png_ptr, fp);
//let libpng know you already read the first 8 bytes
png_set_sig_bytes(png_ptr, 8);
// read all the info up to the image data
png_read_info(png_ptr, info_ptr); // THIS CAUSES APP TO CRASH
//variables to pass to get info
int bit_depth, color_type;
png_uint_32 twidth, theight;
// get info about png
png_get_IHDR(png_ptr, info_ptr, &twidth, &theight, &bit_depth, &color_type,
NULL, NULL, NULL);
//update width and height based on png info
width = twidth;
height = theight;
// Update the png info struct.
png_read_update_info(png_ptr, info_ptr);
// Row size in bytes.
int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
// Allocate the image_data as a big block, to be given to opengl
png_byte *image_data = new png_byte[rowbytes * height];
if (!image_data)
{
//clean up memory and close stuff
Com.warning( "loadImage: failed to allocate memory for %", fileName );
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
//row_pointers is for pointing to image_data for reading the png with libpng
png_bytep *row_pointers = new png_bytep[height];
if (!row_pointers)
{
Com.warning( "loadImage: failed to allocate memory for %", fileName );
//clean up memory and close stuff
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
delete[] image_data;
fclose(fp);
return TEXTURE_LOAD_ERROR;
}
// set the individual row_pointers to point at the correct offsets of image_data
for (int i = 0; i < height; ++i)
row_pointers[height - 1 - i] = image_data + i * rowbytes;
//read the png into image_data through row_pointers
png_read_image(png_ptr, row_pointers);
//Now generate the OpenGL texture object
GLuint texture;
glGenTextures(1, &texture);
glBindTexture( GL_TEXTURE_2D, texture );
glTexImage2D(GL_TEXTURE_2D,0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid*) image_data);
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
//clean up memory and close stuff
png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
delete[] image_data;
delete[] row_pointers;
fclose(fp);
return texture;
}[/source]
Edit: I'm using Visual C++ 2005 Express, GLFW, GLEW and Windows XP SP3.
