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# Sampler

class Sampler

  Returned by `Context.sampler()`

  A Sampler Object is an OpenGL Object that stores the sampling parameters for a Texture access inside of a shader.

  When a sampler object is bound to a texture image unit, the internal sampling parameters for a texture bound to the same image unit are all ignored. Instead, the sampling parameters are taken from this sampler object.

  Unlike textures, a samplers state can also be changed freely be at any time without the sampler object being bound/in use.

  Samplers are bound to a texture unit and not a texture itself. Be careful with leaving samplers bound to texture units as it can cause texture incompleteness issues (the texture bind is ignored).

  Sampler bindings do clear automatically between every frame so a texture unit need at least one bind/use per frame.

## Methods

Sampler.use(location: int = 0) → None:

  Bind the sampler to a texture unit.

  Parameters:

    location (int) – The texture unit

Sampler.clear(location: int = 0) → None:

  Clear the sampler binding on a texture unit.

  Parameters:

    location (int) – The texture unit

Sampler.assign(index: int) → tuple

  Helper method for assigning samplers to scopes.

  Example:

      s1 = ctx.sampler(...)
      s2 = ctx.sampler(...)
      ctx.scope(samplers=(s1.assign(0), s1.assign(1)), ...)mpler

Sampler.release()

## Attributes

Sampler.texture: Texture

  The texture object to sample.

Sampler.repeat_x: bool

  The x repeat flag for the sampler (Default `True`).

  Example:

      # Enable texture repeat (GL_REPEAT)
      sampler.repeat_x = True

      # Disable texture repeat (GL_CLAMP_TO_EDGE)
      sampler.repeat_x = False

Sampler.repeat_y: bool

  The y repeat flag for the sampler (Default `True`).

  Example:

      # Enable texture repeat (GL_REPEAT)
      sampler.repeat_y = True

      # Disable texture repeat (GL_CLAMP_TO_EDGE)
      sampler.repeat_y = False

Sampler.repeat_z: bool

  The z repeat flag for the sampler (Default `True`).

  Example:

      # Enable texture repeat (GL_REPEAT)
      sampler.repeat_z = True

      # Disable texture repeat (GL_CLAMP_TO_EDGE)
      sampler.repeat_z = False

Sampler.filter: tuple

  The minification and magnification filter for the sampler.

  (Default `(moderngl.LINEAR. moderngl.LINEAR)`)

  Example:

      sampler.filter == (moderngl.NEAREST, moderngl.NEAREST)
      sampler.filter == (moderngl.LINEAR_MIPMAP_LINEAR, moderngl.LINEAR)
      sampler.filter == (moderngl.NEAREST_MIPMAP_LINEAR, moderngl.NEAREST)
      sampler.filter == (moderngl.LINEAR_MIPMAP_NEAREST, moderngl.NEAREST)

Sampler.compare_func: tuple

  The compare function for a depth textures (Default `'?'`).

  By default samplers don’t have depth comparison mode enabled. This means that depth texture values can be read as a `sampler2D` using `texture()` in a GLSL shader by default.

  When setting this property to a valid compare mode, `GL_TEXTURE_COMPARE_MODE` is set to `GL_COMPARE_REF_TO_TEXTURE` so that texture lookup functions in GLSL will return a depth comparison result instead of the actual depth value.

  Accepted compare functions:

      .compare_func = ''    # Disale depth comparison completely
      sampler.compare_func = '<='  # GL_LEQUAL
      sampler.compare_func = '<'   # GL_LESS
      sampler.compare_func = '>='  # GL_GEQUAL
      sampler.compare_func = '>'   # GL_GREATER
      sampler.compare_func = '=='  # GL_EQUAL
      sampler.compare_func = '!='  # GL_NOTEQUAL
      sampler.compare_func = '0'   # GL_NEVER
      sampler.compare_func = '1'   # GL_ALWAYS

Sampler.anisotropy: float

  Number of samples for anisotropic filtering (Default `1.0`).

  The value will be clamped in range `1.0` and `ctx.max_anisotropy`.

  Any value greater than 1.0 counts as a use of anisotropic filtering:

      # Disable anisotropic filtering
      sampler.anisotropy = 1.0

      # Enable anisotropic filtering suggesting 16 samples as a maximum
      sampler.anisotropy = 16.0

Sampler.border_color: tuple

  The (r, g, b, a) color for the texture border (Default `(0.0, 0.0, 0.0, 0.0)`).

  When setting this value the `repeat_` values are overridden setting the texture wrap to return the border color when outside [0, 1] range.

  Example:

      # Red border color
      sampler.border_color = (1.0, 0.0, 0.0, 0.0)

Sampler.min_lod: float

  Minimum level-of-detail parameter (Default `-1000.0`).

  This floating-point value limits the selection of highest resolution mipmap (lowest mipmap level)

Sampler.max_lod: float

  Minimum level-of-detail parameter (Default `1000.0`).

  This floating-point value limits the selection of the lowest resolution mipmap (highest mipmap level)

Sampler.ctx: Context

  The context this object belongs to

Sampler.glo: int

  The internal OpenGL object. This values is provided for interoperability and debug purposes only.

Sampler.extra: Any

  User defined data.