dassaultsystemes-technology/dspbr-pt

A WebGL2 Enterprise PBR sample renderer

Enterprise PBR Sample Renderer (Demo Viewer)

A WebGL2 GPU path-tracer that runs in your browser.
Features physical materials by implementing the Enterprise PBR Shading Model (DSPBR)

Demo Viewer (glTF drag&drop)

Minimal Demo [ Code ]

Features

• Browser-based, unbiased* GPU path-tracing
• Implements parts of the Enterprise PBR Shading Model (DSPBR)
  • Rough Metal & Dielectrics (opaque/transparent)
    Using energy preserving, multi-scattering GGX BRDF and directional albedo scaling for diffuse/sheen components
  • Sheen
  • Clearcoat
  • Emission
  • Iridescence
• Three.js scene compatibility
• Implements most of the new glTF PBR Next material extensions [1,2] and extension proposal pull requests (marked as PR below).
  • KHR_materials_anisotropy (PR)
  • KHR_materials_clearcoat
  • KHR_materials_emission_strength (PR)
  • KHR_materials_ior
  • KHR_materials_iridescence (PR)
  • KHR_materials_sheen
  • KHR_materials_specular
  • KHR_materials_transmission
  • KHR_materials_volume

Development

# yarn is mandatory as this project uses yarn workspaces
yarn install

# Builds all packages
yarn build

# Launch the demo viewer with HMR enabled -> auto update on code change during development
yarn run dev

License

• Source code license info in LICENSE

dspbr-pt's Issues

how to use EnterprisePBRShadingModel manully in threejs?

the viewer app is automatically load glb with EnterprisePBRShadingModel.
i want to create a cube in threejs with EnterprisePBRShadingModel,how?

glTF alpha transparency not supported

Clear coat normal map seems wrong

It looks like from the khronos-ClearCoatTest that the differences in the 4th and 6th rows may be due to applying the wrong normal map to each surface (since there are two)?

glTF vertex colors not supported

Attenuation color not working?

I'm testing out attenuation colors with this model: KhronosGroup/glTF-Sample-Models#306 (see README).

But, it doesn't look like the attenuation color is present:

No reconstruction filter -> aliasing

Denoising

Your project is fantastic, quite a achievement! I saw another project which is similar to yours, they talk about denoising here in this issue:
hoverinc/ray-tracing-renderer#2
I thought you might have experience in denoising techniques and want to add to the discussion. It would be cool to also see denoising ending up in your project.

transmission is dark

It seems like the attenuation color ends up considerably darker than in any of our rasterizers as a general rule, and I can't think of a path-tracer reason for that. It's especially clear here. Interestingly, khronos-AttenuationTest also shows a disparity between the first row and the others that I don't quite understand. Possibly related?

Support for KHR_materials_sss

dspbr-pt needs a basic brute-force volumetric scattering implementation to support the new SSS extension.

Node transformation parsing broken

Transformation parsing is still broken. This only occurs for some scenes and is most obvious when importing the scenes without rescaling.

Scenes to reproduce the issue (autoScaleOnImport needs to be disabled)

• https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/CesiumMilkTruck
• https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Buggy
• https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/2CylinderEngine

iridescenceThicknessTexture ignored?

iridescenceThicknessTexture seems to be ignored when rendering a glTF material with KHR_materials_iridescence in the online renderer. There should be a noisy perturbation of the thickness, as seen on the right:

Example model:
iridescent_bubble_gltf.zip

    "materials": [
        {
            "name": "bubble",
            "pbrMetallicRoughness": {
                "baseColorFactor": [
                    1,
                    1,
                    1,
                    1
                ],
                "metallicFactor": 0.3,
                "roughnessFactor": 0.0
            },
            "doubleSided": true,
            "extensions": {
                "KHR_materials_transmission": {
                    "transmissionFactor": 1
                },
                "KHR_materials_ior": {
                    "ior": 1.0
                },
                "KHR_materials_iridescence": {
                    "iridescenceFactor": 1,
                    "iridescenceThicknessTexture": {
                        "index": 0
                    },
                    "iridescenceThicknessMinimum": 450,
                    "iridescenceThicknessMaximum": 550,
                    "iridescenceIor": 1.6
                }
            }
        }
    ],
    "textures": [
        {
            "sampler": 0,
            "source": 0,
            "name": "bubble_thickness.png"
        }
    ],
    "images": [
        {
            "uri": "bubble_thickness.png"
        }
    ],

Thanks!

New npm release please?

It's been more than a year since your last npm release, but it looks like you've done a lot of work supporting the new glTF extensions. If you push a release, I'll be able to update our ground-truth renders: https://modelviewer.dev/fidelity/

Thanks!

Singular events should not count as bounce

Singular bounce events as for mirror reflections (refractions) currently count as bounce. When rendering with low bounce depth, this results in black shading of very reflective parts of the scene.
Not counting these event should fix this, as the path continues until a light or non-singular surface is found where light contribution can be gathered by direct light sampling.

Backgroud Color seems wrong

KHR_mesh_quantization not supported

The renderer silently fails to load scenes with KHR_mesh_quantization encoded data (reported in #32)

gltf-transform is about to add added a dequantization function that will allow to decode such assets at load time

Support for non-indexed and interleaved geometry

The renderer currently fails silently if given the following types of input geometry:

• non-indexed (or mixed index and non-indexed?)
• interleaved attributes
• mixed component types (e.g. some positions uint8, others uint16)

The error seems to be related to the mergeBufferGeometries step, which displays an error in the console. I'm not sure if it's possible to proceed without merging? three.js does have a mergeVertices utility that can help with creating an index. The other two (de-quantizing, de-interleaving) would require some custom code here.

I'm wondering if it would be an option to pre-process the input glTF file with gltf-transform, to normalize the structure for the path tracer, like:

import { WebIO, VertexLayout } from '@gltf-transform/core';
import { ALL_EXTENSIONS } from '@gltf-transform/extensions';
import { weld, dequantize } from '@gltf-transform/functions';

const io = new WebIO()
  .registerExtensions(ALL_EXTENSIONS)
  .setVertexLayout(VertexLayout.SEPARATE);

// Read.
const document = io.readBinary(inputGLB /* ArrayBuffer */);

// Process.
await document.transform(
  weld(),
  dequantize()
);

// Write.
const outputGLB = io.writeBinary(document);

^the dequantize function doesn't yet exist, but I could add it if that's of interest.

Markdeep Spec is not rendering

I clicked the links in the README but I see markdown source rather than rendered output. Looks like a 404 on the markdeep library:

ThinWalled vs. IOR?

I am seeing odd results in DSPBR when a glTF model uses Transmission without Volume (thin-walled) and no IOR is specified. (third image below)

However when KHR-materials_ior is added at 1.0 for the air inside the bubble, then the iridescence looks correct. (fourth image below)

Shouldn't the absence of the KHR-materials_volume extension cause thin-walled rendering, which assume air is behind/inside the mesh surface?

Energy loss on higher sample counts

Rendering darkens on accumlation of many samples

Loading error with KHR_materials_unlit

metal-rough-transm.zip

1. https://dassaultsystemes-technology.github.io/dspbr-pt/

2. Drag and drop the unzippped glTF and its resources.
   Result: the loading animation never ends.

3. Disable "use pathtracing".
   Result: the glTF model is now visible.

4. Enable "use pathtracing"
   Result: the model for "metal-roughness-0.01" reappears, along with the loading animation.

Thanks!

Nice results

Quick test - Nice results !

https://sketchfab.com/3d-models/police-drone-7f014be2705844c49152bfa1eb66fd86
model by: [email protected]

http://lighttracer.org/app.html?open=https://dl.dropboxusercontent.com/s/6aadi8vj035zikq/police-drone.glb

Update to latest specular & volume specifications

In the past few weeks, some changes were made to glTF extension specifications for specular and volume.

Can those changes be reflected in this project? Thanks!