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Panda3D Manual: Depth Test and Depth Write

Contents

Enabling or Disabling the Depth Buffer

By default, depth buffer is enabled and functions normally. It is possible to turn off the use of the depth buffer. It is also possible to alter the behavior of the depth buffer.

The most common thing to want to do is to disable the depth-write. This means that geometry will still be tested against the depth buffer, but it will not affect the depth buffer. This is often used when rendering objects such as particles that are transparent. To disable or enable the depth-write, use:

nodePath.setDepthWrite(False)  # Disable
nodePath.setDepthWrite(True)   # Enable

It may also be desirable to disable the depth-test. This means that the geometry pays no attention whatsoever to the contents of the depth-buffer. This is often used for rendering things like heads-up displays, which have no relation to the 3D depth of the scene. To disable or enable the depth-test, use:

nodePath.setDepthTest(False)  # Disable
nodePath.setDepthTest(True)   # Enable

One can remove these settings using clearDepthTest and clearDepthWrite.

Altering the Depth Buffer

Occasionally, it is desirable to alter the functionality of the depth buffer. Normally, the depth buffer only renders things that are in front, but it can be made to render things that are in back, or equal. This is rarely used, but it can be important for certain unusual algorithms like shadow volumes.

To do this, you need to use the DepthTestAttrib directly, in one of the following variants:

nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MNone))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MNever))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MLess))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MEqual))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MLessEqual))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MGreater))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MGreaterEqual))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MNotEqual))
nodePath.setAttrib(DepthTestAttrib.make(RenderAttrib.MAlways))

Depth Sorting

When turning depth test off, it is sometimes desirable to use depth sorting instead. Depth sorting is controlled by the culling system, which can be controlled by the CullBinAttrib.

Transparency

Certain settings of the TransparencyAttrib can also affect the depth-test.