${className} ${this.name}: the back buffer depth/stencil tex

Error message

${className} ${this.name}: the back buffer depth/stencil texture is the only depth texture allowed when the target is the back buffer color

What it means

When an ObjectRendererTask renders directly to the frame graph's back buffer color texture, the only depth attachment permitted is the back buffer's own depth/stencil texture. Supplying any custom depthTexture would conflict with the back buffer's depth, so _checkTextureCompatibility throws.

Source

Thrown at packages/dev/core/src/FrameGraph/Tasks/Rendering/objectRendererTask.ts:548

            this._frameGraph.textureManager.resolveDanglingHandle(this.outputDepthTexture, this.depthTexture);
        }
    }

    protected _checkParameters() {
        if (this.targetTexture === undefined || this.objectList === undefined || this.camera === undefined) {
            throw new Error(`FrameGraphObjectRendererTask ${this.name}: targetTexture, objectList, and camera are required`);
        }
    }

    protected _checkTextureCompatibility(targetTextures: FrameGraphTextureHandle[]): boolean {
        const className = this.getClassName();

        let outputTextureDescription = targetTextures.length > 0 ? this._frameGraph.textureManager.getTextureDescription(targetTextures[0]) : null;
        let depthEnabled = false;

        if (this.depthTexture !== undefined) {
            if (outputTextureDescription && this.depthTexture !== backbufferDepthStencilTextureHandle && targetTextures[0] === backbufferColorTextureHandle) {
                throw new Error(`${className} ${this.name}: the back buffer depth/stencil texture is the only depth texture allowed when the target is the back buffer color`);
            }

            const depthTextureDescription = this._frameGraph.textureManager.getTextureDescription(this.depthTexture);
            if (!outputTextureDescription) {
                outputTextureDescription = depthTextureDescription;
            }
            if (depthTextureDescription.options.samples !== outputTextureDescription.options.samples) {
                throw new Error(
                    `${className} ${this.name}: the depth texture "${depthTextureDescription.options.labels?.[0] ?? "noname"}" (${depthTextureDescription.options.samples} samples) and the output texture "${outputTextureDescription.options.labels?.[0] ?? "noname"}" (${outputTextureDescription.options.samples} samples) must have the same number of samples`
                );
            }

            if (depthTextureDescription.size.width !== outputTextureDescription.size.width || depthTextureDescription.size.height !== outputTextureDescription.size.height) {
                throw new Error(
                    `${className} ${this.name}: the depth texture (size: ${depthTextureDescription.size.width}x${depthTextureDescription.size.height}) and the target texture (size: ${outputTextureDescription.size.width}x${outputTextureDescription.size.height}) must have the same dimensions.`
                );
            }

View on GitHub (pinned to 0592b347b8)

Solutions

Either remove the custom depthTexture so the back buffer's own depth/stencil is used, or
Render to a non-back-buffer target texture when a custom depth texture is needed.
If back-buffer depth is available as a handle, set depthTexture to the back buffer depth/stencil handle instead of a custom one.

Example fix

// before
task.targetTexture = frameGraph.backBufferColorTexture;
task.depthTexture = myCustomDepthTexture; // not allowed

// after
task.targetTexture = frameGraph.backBufferColorTexture;
task.depthTexture = undefined; // use back buffer depth/stencil

Defensive patterns

Strategy: validation

Validate before calling

if (task.targetTexture === frameGraph.backBufferColorTexture.handle && task.depthTexture !== undefined && task.depthTexture !== frameGraph.backBufferDepthStencilTexture.handle) {
    throw new Error('Custom depth not allowed when targeting back buffer color');
}

Try / catch

try {
    frameGraph.build();
} catch (e) {
    if (String(e).includes('back buffer depth/stencil texture is the only depth texture allowed')) {
        task.depthTexture = undefined; // fall back to back buffer depth
        frameGraph.build();
    } else throw e;
}

Prevention

Decide up front whether a task targets the back buffer or an offscreen texture; configure depth accordingly.
Do not share one task configuration between back-buffer and offscreen targets.
When targeting the back buffer, omit depthTexture entirely unless you specifically need the back buffer depth handle.

When it happens

Trigger: Setting task.depthTexture to a custom depth texture (any handle other than the back buffer depth/stencil handle) while task.targetTexture equals the back buffer color texture handle.

Common situations: Reusing depth texture configuration from an offscreen-target task and switching targetTexture to the back buffer; assuming custom depth works with back-buffer rendering; sharing one task definition between window and texture targets.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/0ea32c24024b65f7. Report an issue: GitHub.