Need faster result than pixel() to get filter output

[jpvaillancourt]

I have a very simple graphics with a custom filter that creates a Noise + basic sin calculation to create a wave displacement map. I need to get the result of only one channel and I'm currently using :

renderer.extract.pixels()

But it is VERY slow. Is there a way to get the data output directly from the shader instead? I'm not sure if I'm explaining well enough...

In other words, I would like to have the gl_FragColor of each pixels directly after the filter calculation. I'm pretty sure it should be possible instead of waiting for the Renderer to calculate the exact same result based on the position of the graphics, and then extracting it.

I have search for several hours everywhere...

Here's what I have at the moment (in Typescript), but the pixel() consume 49% of the tick duration.

private createTextureDeformer() : void {
        this._pixiApp = new PIXI.Application(this.textureResolution + 1, this.textureResolution + 1, {
            transparent : <any> "notMultiplied",
        });

        var uniforms : any = {};
        uniforms.u_time = {
            type : 'f',
            value : 0
        };

        uniforms.u_size = {
            type : 'i',
            value : this.textureResolution
        };


        this._textureFilter = new PIXI.Filter(null, this.getTextureDeformerShader(), uniforms);

        var graphics : PIXI.Graphics = new PIXI.Graphics();
        graphics.drawRect(0, 0, this.textureResolution, this.textureResolution);

        graphics.filters = [this._textureFilter];
        this._pixiApp.stage.addChild(graphics);

        if(this.debug) {
            document.body.appendChild(this._pixiApp.view);
            this._pixiApp.view.id = 'pixi-canvas';
        }

        this.renderTextureDeformer(0);
    }

private renderTextureDeformer(delta : number) : void {
        this._textureFilter.uniforms.u_time += delta / 1000;
        this._texturePixels = this._pixiApp.renderer.extract.pixels() as Uint8Array;
    }

 

[xerver]

If you don't need the pixel data on the CPU then don't extract it, just write it to a framebuffer and use it in a different shader. If you do need the pixels on the CPU (becuase you need to write them to disk or some such) then this is the only way.