crystal.Painter

A Wrapper which applies a shader when drawing its child. This element draws in two passes:

1. Its descendents are rendered to an offscreen canvas.
2. The resulting canvas is drawn to the screen with the desired shader applied.

If no shader is set on this element, it draws in a single pass (skipping the intermediate canvas).

The child of a Painter has a Basic Joint to adjust positioning preferences (padding, alignment, etc.).

RoundedCorners is an example of a Painter element.

Constructor

crystal.Painter:new(shader)

The optional shader parameter should be a love.Shader.

Methods

Name	Description
set_shader	Sets or clears the shader used to draw this element.
shader	Returns the shader used to draw this element, if any.

Callbacks

Name	Description
configure_shader	Called right before the element is drawn.

Examples

This example illustrates what implementing your own Painter class looks like:

local MyPainter = Class("MyPainter", crystal.Painter);

MyPainter.init = function(self)
  MyPainter.super.init(self, crystal.assets.get("assets/my_shader.glsl"));
  self.my_param = 0;
end

MyPainter.set_param = function(self, value)
  self.my_param = value;
end

MyPainter.configure_shader = function(self, shader, quad)
  shader:send("my_param", self.my_param);
end