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

# Gl.Hint (gb.opengl)

Static Sub Hint ( Target As Integer, Mode As Integer )

Specify implementation-specific hints.

### Parameters

target

  Specifies a symbolic constant indicating the behavior to be controlled. Gl.LINE_SMOOTH_HINT, Gl.POLYGON_SMOOTH_HINT, Gl.TEXTURE_COMPRESSION_HINT, and Gl.FRAGMENT_SHADER_DERIVATIVE_HINT are accepted.

mode

  Specifies a symbolic constant indicating the desired behavior. Gl.FASTEST, Gl.NICEST, and Gl.DONT_CARE are accepted.

### Description

Certain aspects of GL behavior, when there is room for interpretation, can be controlled with hints. A hint is specified with two arguments. target is a symbolic constant indicating the behavior to be controlled, and mode is another symbolic constant indicating the desired behavior. The initial value for each target is Gl.DONT_CARE. mode can be one of the following:

Gl.FASTEST

  The most efficient option should be chosen.

Gl.NICEST

  The most correct, or highest quality, option should be chosen.

Gl.DONT_CARE

  No preference.

Though the implementation aspects that can be hinted are well defined, the interpretation of the hints depends on the implementation. The hint aspects that can be specified with target, along with suggested semantics, are as follows:

Gl.FRAGMENT_SHADER_DERIVATIVE_HINT

  Indicates the accuracy of the derivative calculation for the GL shading language fragment processing built-in functions: dFdx, dFdy, and fwidth.

Gl.LINE_SMOOTH_HINT

  Indicates the sampling quality of antialiased lines. If a larger filter function is applied, hinting Gl.NICEST can result in more pixel fragments being generated during rasterization.

Gl.POLYGON_SMOOTH_HINT

  Indicates the sampling quality of antialiased polygons. Hinting Gl.NICEST can result in more pixel fragments being generated during rasterization, if a larger filter function is applied.

Gl.TEXTURE_COMPRESSION_HINT

  Indicates the quality and performance of the compressing texture images. Hinting Gl.FASTEST indicates that texture images should be compressed as quickly as possible, while Gl.NICEST indicates that texture images should be compressed with as little image quality loss as possible. Gl.NICEST should be selected if the texture is to be retrieved by Gl.GetCompressedTexImage for reuse.

### Notes

The interpretation of hints depends on the implementation. Some implementations ignore Gl.Hint settings.

### Errors

Gl.INVALID_ENUM is generated if either target or mode is not an accepted value.

See original documentation on OpenGL website