koobas.hobune.stream
Texture sampling will move when sampled same position.
I'm facing a sampling problem. I'm trying to use Compute Shader via SampleLevel method.
I've written shader code like below.
[numthreads(8,8,1)]
void Test(uint2 id : SV_DispatchThreadID)
{
float w, h;
_SourceTexture.GetDimensions(w, h);
float2 uv = float2(id.x/w, id.y/h);
float4 t = _SourceTexture.SampleLevel(_LinearClamp, uv, 0);
_ResultTexture[id] = t;
}
And it will be dispatched like below.
int kernel = _shader.FindKernel("Test");
_shader.SetTexture(kernel, "_SourceTexture", _previewBuffer.Current);
_shader.SetTexture(kernel, "_ResultTexture", _previewBuffer.Other);
_shader.Dispatch(kernel, _previewBuffer.Width / 8, _previewBuffer.Height / 8, 1);
_previewBuffer.Swap();
_preview.texture = _previewBuffer.Current;
The texture will swap each frame.
So I'm wondering why the shader code sampled same position but the texture will move toward up-right.
I also attached a movie for the problem.
Does anyone have any idea?
Best Answer
I've solved it myself. The problem is the sampling to left bottom of pixel. I modified a code like below.
float2 uv = float2(id.x/w, id.y/h) + float2(0.5/w, 0.5/h);
It will access to the center of pixel. Then it will fix.
