keepBuffers webgpu

Wagner · April 3, 2025, 9:21am

Is it possible to implement keepbuffer for webgpu, similar to webgl2?

playcanvas/engine/blob/main/src/platform/graphics/webgpu/webgpu-graphics-device.js#L545


      
                      }
                      _uniqueLocations.set(location, name);
                  }
              };
          
              validateVB(vb0);
              validateVB(vb1);
              _uniqueLocations.clear();
          }
          
          draw(primitive, numInstances = 1, keepBuffers) {
          
              if (this.shader.ready && !this.shader.failed) {
          
                  WebgpuDebug.validate(this);
          
                  const passEncoder = this.passEncoder;
                  Debug.assert(passEncoder);
          
                  // vertex buffers
                  const vb0 = this.vertexBuffers[0];

@mvaligursky

mvaligursky · April 3, 2025, 9:34am

What’s the goal of it?
WebGL implements this primarily for XR multiview rendering, which WebGPU does not support yet.

Wagner · April 3, 2025, 9:38am

I have a lot of similar models that only differ in a few shader uniforms, I would like to save the buffers and uniforms and update only those uniforms.

Because you have to constantly render mesh instances, re-assigning all the data for the model and shader to them, the fps drops.

mvaligursky · April 3, 2025, 9:51am

There are better way to get performance for this, for example: Consider using WebGPU Bundles to improve performance · Issue #5740 · playcanvas/engine · GitHub which will be coming in the future.

WebGPU uploads uniforms in uniform buffers, so updating just few uniforms is not an option. But for this, this should be a great help, which is again on a long TODO list: Implement material level uniform buffer (WebGPU initially) · Issue #6157 · playcanvas/engine · GitHub