Determines whether the depth/stencil buffer is cleared before the panel is rendered.
Only the first panel (according to the sorting order) must clear the depth/stencil buffer.
Subsequent panels should not clear it. Unnecessary clearing can significantly degrade performance.
UI Toolkit uses the depth/stencil buffer to perform masking operations, refer to Overflow.Hidden for more inforamtion.
The renderer strategically positions masking shapes to intentionally fail the depth test.
This failure triggers efficient push/pop operations within the stencil buffer, enabling effective masking.
To ensure this process functions correctly, the depth buffer values
must be within a predetermined range. When UI Toolkit clears the depth buffer, it leaves
a gap (controlled by PanelSettings.depthClearValue) where masks can be positioned to fail
the test. Additionally, UI Toolkit clears the stencil because the bits are used to store data
representing the stack of masking shapes.
An incorrect depth/stencil buffer clearing can cause malfunctions with the masking system. Such
as:
- Masking shapes might become visible
- Normal meshes might become invisible
- Complete masking failure