How to modify a shader's parameters in runtime?

Question

I have a shader and I want it to get more extreme with the players speed. How would I edit this shader's parameters in runtime?

Answer 1

You need to get a reference to the material. If it's a CanvasItem (2D) you can get it with material. If it's a MeshInstance, you can use its GeometryInstance.material_override or Mesh.surface_get_material or PrimitiveMesh.material. I've linked to the class docs if you need details.

After that it depends on what kind of material it is:

• ShaderMaterial: You can change any uniform parameter with set_shader_param()
  https://docs.godotengine.org/en/3.1/classes/class_shadermaterial.html

• SpatialMaterial: set the parameter name directly:
  https://docs.godotengine.org/en/3.1/classes/class_spatialmaterial.html

Comments

For example, if you have a boolean parameter, grayscale, to turn on and off grayscale:
$Sprite.material.setshaderparam('grayscale',true)