libgdx/libgdx · error · GdxRuntimeException

compressed textures not supported by GWT WebGL backend

Error message

compressed textures not supported by GWT WebGL backend

What it means

Error "compressed textures not supported by GWT WebGL backend" thrown in libgdx/libgdx.

Source

Thrown at backends/gdx-backends-gwt/src/com/badlogic/gdx/backends/gwt/GwtGL20.java:322

	public void glClearStencil (int s) {
		gl.clearStencil(s);
	}

	@Override
	public void glColorMask (boolean red, boolean green, boolean blue, boolean alpha) {
		gl.colorMask(red, green, blue, alpha);
	}

	@Override
	public void glCompileShader (int shader) {
		WebGLShader glShader = shaders.get(shader);
		gl.compileShader(glShader);
	}

	@Override
	public void glCompressedTexImage2D (int target, int level, int internalformat, int width, int height, int border,
		int imageSize, Buffer data) {
		throw new GdxRuntimeException("compressed textures not supported by GWT WebGL backend");
	}

	@Override
	public void glCompressedTexSubImage2D (int target, int level, int xoffset, int yoffset, int width, int height, int format,
		int imageSize, Buffer data) {
		throw new GdxRuntimeException("compressed textures not supported by GWT WebGL backend");
	}

	@Override
	public void glCopyTexImage2D (int target, int level, int internalformat, int x, int y, int width, int height, int border) {
		gl.copyTexImage2D(target, level, internalformat, x, y, width, height, border);
	}

	@Override
	public void glCopyTexSubImage2D (int target, int level, int xoffset, int yoffset, int x, int y, int width, int height) {
		gl.copyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
	}

View on GitHub (pinned to 97f4086187)

Solutions

1. Do not call glCompressedTexImage2D/glCompressedTexSubImage2D on GWT WebGL; use plain glTexImage2D with uncompressed RGBA data, or provide precompressed textures via a WebGL compressed-texture extension path of your own.

When it happens

Trigger: Thrown at backends/gdx-backends-gwt/src/com/badlogic/gdx/backends/gwt/GwtGL20.java:322 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of libgdx/libgdx@97f4086187 (2026-08-14). Data as JSON: /api/errors/d9d1e4cae19b96c6. Report an issue: GitHub.