Fix: USD: Wrong UsdUVTexture rgb output type. #114728

Michael Kowalski · 2023-11-11T02:10:05+01:00

Michael Kowalski commented

2023-11-11 02:10:05 +01:00

This fixes a bug where the rgb UsdUVTexture shader output
attributes were created with incorrect type color3f when
connected to UsdPreviewSurface diffuseColor and emissiveColor
inputs. The UsdPreviewSurface specification requires the
UsdUVTexture rgb output to be of type float3.

This was happening because the UsdUVTexture outputs were created
implicitly by the call to UsdShadeInput::ConnectToSource(). I.e.,
because the diffuseColor and emissiveColor inputs are of type
color3f, this was the type assigned by default to the rgb source
attributes as well.

Now explicitly creating the UsdUVTexture shader output attributes
with the correct types.

Please see the texture reader specification for details on the expected UsdUVTexture output types.

To test, export the attached usd_uv_texture_export_test.blend to USDA
and examine the output file in a text editor. Without the fix, the Image_Texture
shader has attribute color3f outputs:rgb, with the incorrect type. With the fix,
the attribute is correctly saved as float3 outputs:rgb.

The attached usd_uv_texture_export_test_bad.usda and usd_uv_texture_export_test_good.usda
are examples of output before and after the fix, respectively.

This fixes a bug where the rgb UsdUVTexture shader output attributes were created with incorrect type color3f when connected to UsdPreviewSurface diffuseColor and emissiveColor inputs. The UsdPreviewSurface specification requires the UsdUVTexture rgb output to be of type float3. This was happening because the UsdUVTexture outputs were created implicitly by the call to UsdShadeInput::ConnectToSource(). I.e., because the diffuseColor and emissiveColor inputs are of type color3f, this was the type assigned by default to the rgb source attributes as well. Now explicitly creating the UsdUVTexture shader output attributes with the correct types. Please see the [texture reader specification](https://openusd.org/release/spec_usdpreviewsurface.html#texture-reader) for details on the expected UsdUVTexture output types. To test, export the attached `usd_uv_texture_export_test.blend` to USDA and examine the output file in a text editor. Without the fix, the `Image_Texture` shader has attribute `color3f outputs:rgb`, with the incorrect type. With the fix, the attribute is correctly saved as `float3 outputs:rgb`. The attached `usd_uv_texture_export_test_bad.usda` and `usd_uv_texture_export_test_good.usda` are examples of output before and after the fix, respectively.

usd_uv_texture_export_test.blend

1.2 MiB

usd_uv_texture_export_test_bad.usda

4.2 KiB

usd_uv_texture_export_test_good.usda

4.2 KiB

Michael Kowalski added 1 commit 2023-11-11 02:10:19 +01:00

8770cb07d6 Fix: USD: Wrong UsdUVTexture rgb output type.

This fixes a bug where the rgb UsdUVTexture shader output
attributes were created with incorrect type color3f when
connected to UsdPreviewSurface diffuseColor and emissiveColor
inputs. The UsdPreviewSurface specification requires the
UsdUVTexture rgb output to be of type float3.

This was happening because the UsdUVTexture outputs were created
implicitly by the call to UsdShadeInput::ConnectToSource().  I.e.,
because the diffuseColor and emissiveColor inputs are of type
color3f, this was the type assigned by default to the rgb source
attributes as well.

Now explicitly creating the UsdUVTexture shader output attributes
with the correct types.

Michael Kowalski added this to the USD project 2023-11-11 02:33:12 +01:00

Michael Kowalski added the

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Fix: USD: Wrong UsdUVTexture rgb output type. #114728