remotion-dev/remotion · error · Error

Failed to create WebGL shader

Error message

Failed to create WebGL shader

What it means

The skew() effect's WebGL2 backend could not allocate a shader object: gl.createShader() returned null inside compileShader() in packages/effects/src/skew.ts. A null return means the WebGL2 context is lost, resource-exhausted, or backed by a non-conformant driver, so the library cannot compile the vertex/fragment shaders it needs and throws before setup completes. This is an environment failure, not a parameter error — the context was acquired moments earlier (otherwise createWebGL2ContextError would have fired first).

Source

Thrown at packages/effects/src/skew.ts:164

	vec2 sourceUv = vec2(sourceX, sourceY) / uResolution + uOrigin;

	if (any(lessThan(sourceUv, vec2(0.0))) || any(greaterThan(sourceUv, vec2(1.0)))) {
		fragColor = vec4(0.0);
		return;
	}

	fragColor = texture(uSource, sourceUv);
}
`;

const compileShader = (
	gl: WebGL2RenderingContext,
	type: number,
	source: string,
): WebGLShader => {
	const shader = gl.createShader(type);
	if (!shader) {
		throw new Error('Failed to create WebGL shader');
	}

	gl.shaderSource(shader, source);
	gl.compileShader(shader);
	if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
		const log = gl.getShaderInfoLog(shader);
		gl.deleteShader(shader);
		throw new Error(`Skew shader compile failed: ${log ?? '(no log)'}`);
	}

	return shader;
};

const setupSkew = (target: HTMLCanvasElement): SkewState => {
	const gl = target.getContext('webgl2', {
		premultipliedAlpha: true,
		alpha: true,
		preserveDrawingBuffer: true,

View on GitHub (pinned to 78fe4bb3fd)

Solutions

1. Render with the ANGLE backend: add --gl=angle to the CLI, set chromiumOptions.gl='angle' in renderMediaOnLambda()/renderMedia(), or pick 'angle' in Studio Advanced > OpenGL render backend.
2. Lower concurrency (CLI --concurrency, or concurrency in SSR options) and/or reduce the number of WebGL2 effects stacked on a single frame so the active-context cap is not exceeded.
3. Make sure every effect's cleanup path runs so contexts/textures are released before new ones are allocated; avoid leaking offscreen canvases.
4. Verify the environment actually supports WebGL2 (driver installed, not blacklisted); update GPU drivers or run on a host with a working GPU/ANGLE setup.

Example fix

// before
await renderMedia({ composition, serveUrl, codec: 'h264' });
// npx remotion render main MyComp out.mp4

// after
await renderMedia({
  composition,
  serveUrl,
  codec: 'h264',
  chromiumOptions: { gl: 'angle' },
});
// npx remotion render main MyComp out.mp4 --gl=angle

// Pre-flight: confirm WebGL2 is usable before relying on skew().
// Note: this only catches 'no WebGL2 at all' — a createShader() null
// typically means context LOSS after acquisition, which is not detectable up front.
function supportsWebGL2Effect(): boolean {
  try {
    const c = document.createElement('canvas');
    const gl = c.getContext('webgl2');
    return !!gl;
  } catch {
    return false;
  }
}
if (!supportsWebGL2Effect()) {
  throw new Error('skew() requires WebGL2, which is unavailable in this environment');
}

try {
  // using skew() in a render or component
  await renderMedia({ composition, codec: 'h264', chromiumOptions: { gl: 'angle' } });
} catch (err) {
  if (err instanceof Error && /Failed to create WebGL shader/.test(err.message)) {
    // context was acquired but a shader could not be allocated: treat as env failure
    console.error('WebGL2 resource allocation failed for skew(). Retry with --gl=angle or lower concurrency.', err);
    throw err;
  }
  throw err;
}

When it happens

Trigger: Calling skew({...}) in a render where the WebGL2 context acquired in setupSkew() has entered a lost state, or where the process already holds too many live WebGL contexts (browsers cap active contexts, commonly ~16) so a freshly-acquired context is immediately unusable. Also reproducible under GPU memory pressure or a driver reset between getContext() and createShader().

Common situations: Headless Chromium rendering without --gl=angle; many parallel frames each stacking multiple WebGL2 effects; SwiftShader/llvmpipe software fallback under load; a machine whose GPU driver crashed and the context was not recovered; CI runners with no real GPU.

Related errors

• Failed to create WebGL program
• Failed to create WebGL buffer
• Failed to create WebGL geometry
• Failed to create WebGL texture
• Failed to create WebGL shader

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/92dbc7a08673b2ce. Report an issue: GitHub.