Function ggez::graphics::mul_transform

pub fn mul_transform<M>(context: &mut Context, transform: M) where
    M: Into<ColumnMatrix4<f32>>, 

Premultiplies the given transform with the current model transform.

You must call apply_transformations(ctx) after calling this to apply these changes and recalculate the underlying MVP matrix.

A DrawParam can be converted into an appropriate transform matrix by turning it into a DrawTransform:

let param = /* DrawParam building */
let transform = param.to_matrix();
graphics::mul_transform(ctx, transform);