Gambas Documentation - /comp/gb.opengl/gl/depthfunc

/comp/gb.opengl/gl/depthfunc

# Gl.DepthFunc (gb.opengl)

Static Sub DepthFunc ( Function As Integer )

Specify the value used for depth buffer comparisons.

### Parameters

func

  Specifies the depth comparison function. Symbolic constants Gl.NEVER, Gl.LESS, Gl.EQUAL, Gl.LEQUAL, Gl.GREATER, Gl.NOTEQUAL, Gl.GEQUAL, and Gl.ALWAYS are accepted. The initial value is Gl.LESS.

### Description

Gl.DepthFunc specifies the function used to compare each incoming pixel depth value with the depth value present in the depth buffer. The comparison is performed only if depth testing is enabled. (See Gl.Enable and Gl.Disable of Gl.DEPTH_TEST.)

func specifies the conditions under which the pixel will be drawn. The comparison functions are as follows:

Gl.NEVER

  Never passes.

Gl.LESS

  Passes if the incoming depth value is less than the stored depth value.

Gl.EQUAL

  Passes if the incoming depth value is equal to the stored depth value.

Gl.LEQUAL

  Passes if the incoming depth value is less than or equal to the stored depth value.

Gl.GREATER

  Passes if the incoming depth value is greater than the stored depth value.

Gl.NOTEQUAL

  Passes if the incoming depth value is not equal to the stored depth value.

Gl.GEQUAL

  Passes if the incoming depth value is greater than or equal to the stored depth value.

Gl.ALWAYS

  Always passes.

The initial value of func is Gl.LESS. Initially, depth testing is disabled. If depth testing is disabled or if no depth buffer exists, it is as if the depth test always passes.

### Notes

Even if the depth buffer exists and the depth mask is non-zero, the depth buffer is not updated if the depth test is disabled. In order to unconditionally write to the depth buffer, the depth test should be enabled and set to Gl.ALWAYS.

### Errors

Gl.INVALID_ENUM is generated if func is not an accepted value.

### Associated Gets

Gl.Get with argument Gl.DEPTH_FUNC

Gl.IsEnabled with argument Gl.DEPTH_TEST

### See also

- Gl.DepthRange,

- Gl.Enable,

Gl.PolygonOffset

See original documentation on OpenGL website