Re: Writing out to file : one tile at a time

You may have to use the Imf::TiledOutputFile class instead of the
TiledRgbaOutputFile class. Insert the RGBA channels into a header
object and into the framebuffer yourself, setting "xTileCoords" and
"yTileCoords" to 1. Then your whitePixels and blackPixels arrays
need only be tileWidth*tileHeight pixels.

The ReadingAndWritingImageFiles pdf has an example of Using the
"General Interface for Writing a Tiled Image File" which you could
adapt to use tileCoords.

On 29/05/14 05:36, Nicholas Yue wrote:

Hi,

I am writing out a checker image to better
understand setFramebuffer and writeTile

The current version I have stores the "entire"
width+height black and white pixel data and choose from there.

I am hoping to find a way, possibly in
setFramebuffer, where I can supply a tile size pixel data (one
black, one white) to choose from rather than an entire
width/height version which defeats the purpose of being able
to handle/process pixels on a tile by tile basis.

8<--------------------------------------------

void writeChecker (const char fileName[],

int width, int height,

int tileWidth, int tileHeight)

{

Imf::TiledRgbaOutputFile out (fileName,

width, height, // image
size

tileWidth, tileHeight,
// tile size

Imf::ONE_LEVEL, //
level mode

Imf::ROUND_DOWN, //
rounding mode

Imf::WRITE_RGBA); //
channels in file // 1

int xTileCount = out.numXTiles();

int yTileCount = out.numYTiles();

RgbaArray whitePixels;

whitePixels.resize(boost::extents[width][height]);

for (RgbaArray::index h=0;h<height;h++)

for (RgbaArray::index w=0;w<width;w++)

{

whitePixels[w][h] = whitePixel;

}

RgbaArray blackPixels;

blackPixels.resize(boost::extents[width][height]);

for (RgbaArray::index h=0;h<height;h++)

for (RgbaArray::index w=0;w<width;w++)

{

blackPixels[w][h] = blackPixel;

}

for (int y=0;y<yTileCount;y++)

for
(int x=0;x<xTileCount;x++)

{

bool
isWhite = checkeredWhite(x,y);

if
(isWhite)

out.setFrameBuffer (whitePixels.data(), 1, tileWidth);

else

out.setFrameBuffer (blackPixels.data(),
1, tileWidth);

out.writeTile
(x,y);

}

}

8<--------------------------------------------

Cheers

--

Nicholas Yue

Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5

Custom Dev - C++ porting, OSX, Linux, Windows

http://au.linkedin.com/in/nicholasyue

https://vimeo.com/channels/naiadtools

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