Is usampler2DArray available in WebGPU?

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1

Is usampler2DArray available in WebGPU ?

uniform highp usampler2DArray someTexture;

...
uvec4 rgba = texture(someTexture, vec3(0, 0, 0));
...

> Error: 'sampler2DArray' : sampler-constructor first argument must match type and dimensionality of constructor type

webgl2 works fine, but webgpu doesn’t.

@mvaligursky

2

my guess is that as usamplers cannot be filtered on WebGPU, you need to use texelFetch instead of texture to read from it.

3

Unfortunately this didn’t help, can you test it?

4

image
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I replaced the type using hot reloading of the javascript file and it helped.

It seems that your types are not being replaced automatically.

// TODO: check littleEndian
// Compress height by x coord [patch0, patch1] ...
// see: CompressedPatchedHeightMap file
export const terrainHeightFactorRGBA8X2VS =
`
    #define uTerrainHeightMap_HOTFIX usampler2DArray(${terrainHeightMapParamName}_texture, ${terrainHeightMapParamName}_sampler)

    float getTerrainHeightFactorFromTexture(ivec3 uv) {
        int level    = uv.b;
        int newLevel = level / 2;
        int chunkX   = level % HM_NUM_CHUNKS_X;
        int shift    = chunkX % 2;
        uvec4 rgba   = texelFetch(uTerrainHeightMap_HOTFIX, ivec3(uv.rg, newLevel), 0);
        uint value   = (shift == 0) ? rgba.r : rgba.g;
        return float(value) / 65535.0;
    }
`;
5

Could you put together a simple repro for this?

6

Yes, sure

1 Like
7

https://playcanvas.com/editor/scene/2116103

8

@mvaligursky

    uniform highp usampler2DArray ${textureParamName};

    float getSomeValuesFromTexture(ivec3 coord) {

        // HOT FIX FOR WEBGPU
        // We change the sampler type, because the standard handler textureParamName does not inherit the type ([U]sampler2DArray)
        #if defined(WEBGPU)
        uvec4 rgba = texelFetch(usampler2DArray(${textureParamName}_texture, ${textureParamName}_sampler), coord, 0);
        #else
        uvec4 rgba = texelFetch(${textureParamName}, coord, 0);
        #endif

        uint value = rgba.r + rgba.g;
        return float(value) / 65535.0;
    }

Replace it and you will see the error, this is only for WebGPU.

    uniform highp usampler2DArray ${textureParamName};

    float getSomeValuesFromTexture(ivec3 coord) {
        uvec4 rgba = texelFetch(${textureParamName}, coord, 0);
        uint value = rgba.r + rgba.g;
        return float(value) / 65535.0;
    }
9

Nice thanks! Got a fix here, that’ll be released with the next engine release: [Fix] Fixes handling uf (u/i)sampler2DArray shader translation for WebGPU by mvaligursky · Pull Request #7120 · playcanvas/engine · GitHub

This line

uniform highp usampler2DArray uTmpTexture;

used to be translated to this:

layout(set = 0, binding = 1) uniform utexture2DArray uTmpTexture_texture;
layout(set = 0, binding = 2) uniform sampler uTmpTexture_sampler;
#define uTmpTexture sampler2DArray(uTmpTexture_texture, uTmpTexture_sampler)

but now it’s correctly this:

layout(set = 0, binding = 1) uniform utexture2DArray uTmpTexture_texture;
layout(set = 0, binding = 2) uniform sampler uTmpTexture_sampler;
#define uTmpTexture usampler2DArray(uTmpTexture_texture, uTmpTexture_sampler)

see the usampler2DArray on the last line

1 Like