# Vulkan Row pitch when copying from VkBuffer to VkImage

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Posted (edited)

I'm working through adding texturing to my program by following vulkan-tutorial.com and was wondering about row pitch. The tutorial states that images must obey the implementation's row pitch amount, which makes sense.

However, the question I'm running into is that I want to use a VkBuffer for staging rather than a separate staging VkImage. From what I can tell, the only way to get the needed row pitch is from the linear tiled staging image. I'm assuming the optimal tiling image will have a different row pitch, and I can't find anything stating either way.

Can I use the row pitch from the destination optimal tiling image, or do I not have to worry about the pitch it in this case?

Edited by CirdanValen

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Using a copy from a VkBuffer instead of from a linear texture is definitely the right track. Trying to use a linear texture for staging is an exercise in frustration because you run into the irritating limitations that apply to linear textures (like limited format/mipmap support).

You shouldn't have to worry about implementation specifics though. Section 18.4 contains pseudocode describing how it expects your texture data to be laid out in your VkBuffer prior to a call to vkCmdCopyBufferToImage.

Assuming you're not using a block compressed format, the spec says:

rowLength = region->bufferRowLength;
if (rowLength == 0)
rowLength = region->imageExtent.width;

imageHeight = region->bufferImageHeight;
if (imageHeight == 0)
imageHeight = region->imageExtent.height;

elementSize = <element size of the format of the src/dstImage>;

address of (x,y,z) = region->bufferOffset + (((z * imageHeight) + y) * rowLength + x) * elementSize;

where x,y,z range from (0,0,0) to region->imageExtent.{width,height,depth}.


There is no need to worry about implementation specifics for staging texture data, that's the driver's problem/responsibility.

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