[Openexr-devel] reading a random tile

[Barnaby Robson]

Could I get some help on reading a single random tile ?

 

The origin of the tile is (x,y)

I am setting up my variables like this. (inTiledFile is a pointer to an Imf::TiledRgbaInputFile)

 

    int dwWidth = inTiledFile->dataWindow().max.x - inTiledFile->dataWindow().min.x + 1;

    int dwHeight = inTiledFile->dataWindow().max.y - inTiledFile->dataWindow().min.y + 1;

 

    int dx = inTiledFile->dataWindow().min.x;

    int dy = inTiledFile->dataWindow().min.y;

 

    int xTile = x / inTiledFile->tileXSize();

    int yTile = y / inTiledFile->tileYSize();

 

I only want to assign enough memory for one tile.

 

    Imf::Array2D<Imf::Rgba> frameBuffer;

    frameBuffer.resizeErase(inTiledFile->tileYSize(), inTiledFile->tileXSize());

 

I am succesful in reading the first tile with this code.

 

    inTiledFile->setFrameBuffer (&frameBuffer[-dy][-dx], 1, inTiledFile->tileXSize());

    inTiledFile->readTile(0,0);

 

But I am not successful reading any other tiles with things like this

 

    inTiledFile->setFrameBuffer (&frameBuffer[-dy][-dx] - x - y * dwWidth, 1, inTiledFile->tileXSize());

    inTiledFile->readTile(0,0);

 

or things like this

 

    inTiledFile->setFrameBuffer (&frameBuffer[-dy][-dx], 1, inTiledFile->tileXSize());

    inTiledFile->readTile(yTile,xTile);

 

 

Does anyone know what the right thing to do is ?

 

Thanks

 

barnaby