how to copy data to float4 texture

Accelerated Computing CUDA CUDA Programming and Performance
1

Hi!

I’m need to initialize some RGB images as 2D textures (so as float3 is not possible, I should use float4). I know that if I want to use both dimensions for indexing, I’ve to copy data from a cudaArray.

The problem is that I can’t find the right way to copy the data I have to the cudaArray.

I’m working with C++, so suppose that I’ve the data into 3 different arrays data.R(), data.G(), data.B(). Now, how can I do cudaMemcpyToArray???

Did I need to copy first data to a float4 array, float per float, and then use cudaMemcpyToArray?

Isn’t there any other more efficient way to do that?

Thanks in advanced!

Enrique

2

There’s no other solution?

3

No, you either need to reformat the data on the CPU (interleaving r,g,b,a) and read it as float4s, or load each color channel as a separate array (which would require three texture reads).

You could do the interleaving in a CUDA kernel, but this probably wouldn’t be much faster.

4

It’s a little bit dissapointing, taking into account that memory operations are such a expensive task…

Thanks for your help!!

Enrique Oriol

5

Thanks everyone for your support, you’re the best!!

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