[webkit-dev] TextureMapperGL stencil bug?

[Baldeva, Arpit]

Hi,

Going through the TextureMapperGL implementation, I see that BeginClip advances the bit plane to the next

clipStack().setStencilIndex(stencilIndex * 2);

However, EndClip does not revert it back before calling clipStack().applyIfNeeded(m_context3D.get());

The applyIfNeeded disables stencil test only if stencilIndex is 1.

if (clipState.stencilIndex == 1)
        context->disable(GraphicsContext3D::STENCIL_TEST);
    else
        context->enable(GraphicsContext3D::STENCIL_TEST);

There is no place in the code that is attempting to reverse the impact of BeginClip. Isn't a right bit shift required in the EndClip call before the applyIfNeeded call? Otherwise, I don't see how EndClip will disable stenciling test ever. The problem is probably more obvious if you have nested clipping.

Note - my observation is based simply on reading the code. Please correct me if I have missed something.

Thanks
Arpit
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