gboisse/gfx

Array of textures

sayan1an opened this issue · 4 comments

sayan1an commented

Hi,

I'm trying to do texture mapping using ray-query. Shader side code would look something like this -

myArrayOfTextures[giveMeMaterialIdx(committedInstanceIndex)].Load(uv)

As such, I need to create an array-of-textures. Texture2DArrays aren't helpful as all slices must have the same resolution. Any suggestions or alternatives?

sayan1an commented

This seems to work (derived from the above example):

Shader:

Buffer<uint> gInstanceIdxToMatIdx;
Texture2D gAlbedoTextures[] : register(space99);
SamplerState gTextureSampler;

// Sample
gAlbedoTextures[gInstanceIdxToMatIdx[instanceIndex]].SampleLevel(gTextureSampler, uv, 0).xyz;

Host:

std::vector<GfxTexture> albedoTextures;
createAndPushAllTextures();
texSampler = gfxCreateSamplerState(..., D3D12_FILTER_MIN_MAG_MIP_POINT,...);
gfxProgramSetParameter(ctx, program, "gTextureSampler", texSampler);
gfxProgramSetParameter(ctx, program, "gAlbedoTextures", albedoTextures.data(), (uint32_t)albedoTextures.size());
gboisse commented

That’s indeed the way to use bindless texturing in gfx.

Note that in some cases, you might need to add NonUniformResourceIndex(), e.g.:

gAlbedoTextures[NonUniformResourceIndex(gInstanceIdxToMatIdx[instanceIndex])].Sample(...);

See here for more information: https://asawicki.info/news_1608_direct3d_12_-_watch_out_for_non-uniform_resource_index

  • 👍1
sayan1an commented

Thank you for pointing that out.