BabylonJS/Babylon.js · error · Error

FrameGraphAnaglyphTask "${this.name}": sourceTexture and lef

Error message

FrameGraphAnaglyphTask "${this.name}": sourceTexture and leftTexture are required

What it means

FrameGraphAnaglyphTask combines a source image with a left-eye image to produce an anaglyph (red/cyan) post-process, so both sourceTexture and leftTexture handles must be set. record() throws if either is undefined before creating the render pass.

Source

Thrown at packages/dev/core/src/FrameGraph/Tasks/PostProcesses/anaglyphTask.ts:32

    public override readonly postProcess: ThinAnaglyphPostProcess;

    /**
     * Constructs a new anaglyph task.
     * @param name The name of the task.
     * @param frameGraph The frame graph this task is associated with.
     * @param thinPostProcess The thin post process to use for the anaglyph effect. If not provided, a new one will be created.
     */
    constructor(name: string, frameGraph: FrameGraph, thinPostProcess?: ThinAnaglyphPostProcess) {
        super(name, frameGraph, thinPostProcess || new ThinAnaglyphPostProcess(name, frameGraph.engine));
    }

    public override getClassName(): string {
        return "FrameGraphAnaglyphTask";
    }

    public override record(skipCreationOfDisabledPasses = false): FrameGraphRenderPass {
        if (this.sourceTexture === undefined || this.leftTexture === undefined) {
            throw new Error(`FrameGraphAnaglyphTask "${this.name}": sourceTexture and leftTexture are required`);
        }

        const pass = super.record(skipCreationOfDisabledPasses, undefined, (context) => {
            context.bindTextureHandle(this._postProcessDrawWrapper.effect!, "leftSampler", this.leftTexture);
        });

        pass.addDependencies(this.leftTexture);

        return pass;
    }
}

View on GitHub (pinned to 0592b347b8)

Solutions

Assign task.sourceTexture to the right/source texture handle before record().
Assign task.leftTexture to the left-eye render target output of a left-camera task.
Ensure both upstream tasks producing these textures are recorded before the anaglyph task.

Example fix

// before
anaglyphTask.sourceTexture = rightCamTask.output;
// after
anaglyphTask.sourceTexture = rightCamTask.output;
anaglyphTask.leftTexture = leftCamTask.output;

Defensive patterns

Strategy: validation

Validate before calling

if (anaglyphTask.sourceTexture === undefined || anaglyphTask.leftTexture === undefined) {
  throw new Error("AnaglyphTask requires sourceTexture and leftTexture");
}

Type guard

function isAnaglyphReady(task: FrameGraphAnaglyphTask): boolean {
  return task.sourceTexture !== undefined && task.leftTexture !== undefined;
}

Try / catch

try {
  anaglyphTask.record();
} catch (e) {
  if (String(e).includes("sourceTexture and leftTexture are required")) {
    console.error("Bind both eyes' render targets before recording the anaglyph task");
  } else throw e;
}

Prevention

Wire right-camera output to sourceTexture and left-camera output to leftTexture together.
Never reuse single-camera post-process wiring for stereo tasks.
Validate all task inputs before calling frameGraph.build().

When it happens

Trigger: anaglyphTask.record() with task.sourceTexture === undefined or task.leftTexture === undefined.

Common situations: Setting only sourceTexture and assuming the left input is optional; forgetting to wire the left-eye render target from a preceding camera/renderer task; copying a non-stereo post-process setup pattern.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/b5c0a5707787445c. Report an issue: GitHub.