Read variable back from Shader

Federico Sucari · 2014-01-31T02:17:54

Dear All, Is there any possibility of doing the following: Create a Shader in HLSL Define a variable in the shader that I would like to read back after processing Load the Shader for drawing Call DX11 functions to draw my stuff After all GPU processing, read back the value of the variable to the program in CPU Any hints if this is possible? Thanks,

Graphics and GPU Programming Programming DX11

Started by fs1 January 26, 2014 12:00 PM

10 comments, last by ankhd 10 years, 3 months ago

kauna

2,925

January 29, 2014 07:14 PM

Just to reminder you that copying data from GPU to CPU (using staging buffer) is usually not very fast. You should check the performance, if you need to make a lot of round-triples.

The slowness may be effect of trying to access the copied data right-away after copy. You should do something else before using the results in order to avoid unnecessary GPU-CPU synchronizations. Ie. the CopyResource is asynchronious, but mapping the data right after will make the CPU to wait the GPU to finish it's tasks.

Cheers!