Hello,
in my application I have the need to read EXR files and split them up into
layers and channels.
I'm currently using OpenExr-1.6.1 on Linux (64 bit).
Therefore I open the file, read the header (dimensions and channels) and
iterate over all channels mentioned there. For each channel I create a
memory area where the data should be put upon reading the content. This
memory area is added to the framebuffer.
This works for all openexr sample images except
Tiles/Spirals.exr
ScanLines/Blobbies.exr
These two make the application crash. It seems that memory gets heavily
corrupted.
Does anyone of you have an idea of what I'm doing wrong?
----- snip -----
#include "Iex.h"
#include "ImfInputFile.h"
#include "ImfHeader.h"
#include "ImfChannelList.h"
#include "ImfFrameBuffer.h"
#include <stdexcept>
#include <vector>
namespace {
/*!
* \brief Determines the number of bytes we need to store a pixel of
type \c n_type
*
* \return 0 on error, a value > 0 otherwise
*/
unsigned char getPixelSize(Imf::PixelType n_type) {
switch (n_type) {
case Imf::UINT:
return sizeof(unsigned int);
case Imf::HALF:
return 2; // per definition, a Half is a 16 bit float value
case Imf::FLOAT:
return sizeof(float);
}
return 0;
}
}
int main(int argc, char** argv) {
Imf::InputFile f(argv[1]);
if (!f.isComplete()) {
throw std::runtime_error("File not complete");
}
const Imf::Header& hdr = f.header();
Imath::Box2i sz = hdr.dataWindow();
size_t width = sz.max.x - sz.min.x + 1;
size_t height = sz.max.y - sz.min.y + 1;
std::vector<char*> buffers; // to free them later
Imf::FrameBuffer frameBuffer;
const Imf::ChannelList& channels(hdr.channels()); // all the channels
// get all the channels, allocate data for the buffer and create a slice
within the FrameBuffer
for (Imf::ChannelList::ConstIterator channel = channels.begin(); channel
!= channels.end(); ++channel) {
// XXX: use an auto_ptr here and put it into a Boost Pointer Container
char *tmpBuf = new char[width * height *
getPixelSize(channel.channel().type) * 2];
buffers.push_back(tmpBuf);
// calculate the address of pixel (0,0)
char *base = tmpBuf + (getPixelSize(channel.channel().type) * (sz.min.x -
sz.min.y * width));
// create a Slice in the Framebuffer
frameBuffer.insert(channel.name(),
Imf::Slice(
channel.channel().type,
base,
getPixelSize(channel.channel().type),
getPixelSize(channel.channel().type) * width, channel.channel().xSampling,
channel.channel().ySampling, 0.0));
}
f.setFrameBuffer(frameBuffer);
f.readPixels(sz.min.y, sz.max.y);
for (std::vector<char*>::iterator i = buffers.begin(); i != buffers.end();
++i) {
std::cerr << "Free buffer at: " << (void*) *i << std::endl;
delete *i;
}
return 0;
}
----- snip -----
Many thanks,
Ronny
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