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use crate::{
    vector::Vector,
    error,
    enums::Axis
};


#[derive(Debug, Clone)]
pub struct Matrix {
    m: Vec<f64>
}

impl Matrix {

    pub fn default() -> Matrix {
        Matrix{
            m:vec![0.0, 0.0, 0.0, 0.0,
                   0.0, 0.0, 0.0, 0.0,
                   0.0, 0.0, 0.0, 0.0,
                   0.0, 0.0, 0.0, 0.0]
        }
    }

    pub fn identity() -> Matrix {
        Matrix{
            m:vec![1.0, 0.0, 0.0, 0.0,
                   0.0, 1.0, 0.0, 0.0,
                   0.0, 0.0, 1.0, 0.0,
                   0.0, 0.0, 0.0, 1.0]
        }
    }

    pub fn new_with_fill(f:f64) -> Matrix {
        Matrix{
            m:vec![f, f, f, f,
                   f, f, f, f,
                   f, f, f, f, 
                   f, f, f, f]
        }
    }

    pub fn new_from_vec(m:&Vec<f64>) -> error::Result<Matrix> {
        if m.len() == 12 {
            Ok(Matrix{
                m:m.clone()
            })
        } else {
            panic!("Array size mismatch");
        }
    }

    pub fn new_from_array(m:&[f64; 12]) -> Matrix {
        Matrix{
            m:m.to_vec()
        }
    }

    pub fn new_with_values(v00:f64, v01:f64, v02:f64,
                           v10:f64, v11:f64, v12:f64,
                           v20:f64, v21:f64, v22:f64) -> Matrix {
        Matrix{
            m:vec![v00, v01, v02,
                   v10, v11, v12,
                   v20, v21, v22]
        }
    }

    fn index(&self, x:usize, y:usize) -> usize {
        y * 4 + x
    }

    pub fn set(&mut self, x:usize, y:usize, v:f64)  {
        let i = self.index(x, y);
        if i < 16 {
            self.m[i] = v;
        } else {
            panic!("Invalid pixel coordinates");
        }
    }

    pub fn get(&self, x:usize, y:usize) -> f64 {
        let i = self.index(x, y);
        if i < 16 {
            self.m[i]
        } else {
            panic!("Invalid pixel coordinates");
        }
    }

    pub fn matmul4(a:&Matrix, b:&Matrix) -> Matrix {

        let mut product = vec![0.0, 0.0, 0.0,
                                0.0, 0.0, 0.0,
                                0.0, 0.0, 0.0];

        for row in 0..3 {
            let ai0 = a.m[(0 << 2) + row];
            let ai1 = a.m[(1 << 2) + row];
            let ai2 = a.m[(2 << 2) + row];

            product[(0 << 2) + row] = ai0 * b.m[(0 << 2) + 0] + ai1 * b.m[(0 << 2) + 1] + ai2 * b.m[(0 << 2) + 2];
            product[(1 << 2) + row] = ai0 * b.m[(1 << 2) + 0] + ai1 * b.m[(1 << 2) + 1] + ai2 * b.m[(1 << 2) + 2];
            product[(2 << 2) + row] = ai0 * b.m[(2 << 2) + 0] + ai1 * b.m[(2 << 2) + 1] + ai2 * b.m[(2 << 2) + 2];
        }

        Matrix::new_from_vec(&product).unwrap()
    }


    pub fn multiply(&self, other:&Matrix) -> Matrix {
        Matrix::matmul4(&self, &other)
    }

    pub fn multiply_vector(&self, other:&Vector) -> Vector {
        let x = other.x * self.m[0 * 4 + 0] + other.y * self.m[1 * 4 + 0] + other.z * self.m[2 * 4 + 0];
		let y = other.x * self.m[0 * 4 + 1] + other.y * self.m[1 * 4 + 1] + other.z * self.m[2 * 4 + 1];
		let z = other.x * self.m[0 * 4 + 2] + other.y * self.m[1 * 4 + 2] + other.z * self.m[2 * 4 + 2];
        Vector::new(x, y, z)
	}

    pub fn scale(&self, x:f64, y:f64, z:f64) -> Matrix {
        Matrix{
            m:vec![self.m[0] * x, self.m[1] * x, self.m[2] * x, 
                   self.m[4] * y, self.m[5] * y, self.m[6] * y,
                   self.m[8] * z, self.m[9] * z, self.m[10] * z]
        }
    }

    pub fn transpose_rotation(&self) -> Matrix {
        let mut t = self.clone();
        t.m[1] = self.m[4];
        t.m[4] = self.m[1];

        t.m[2] = self.m[8];
        t.m[8] = self.m[2];

        t.m[6] = self.m[9];
        t.m[9] = self.m[6];

        t
    }

    pub fn rotate(angle:f64, axis:Axis) -> Matrix {
        let mut m = Matrix::identity();

        let _a = if axis != Axis::YAxis { 
            angle 
        } else { 
            angle * -1.0
        };

        let c = _a.cos();
        let s = _a.sin();

        match axis {
            Axis::XAxis => {
                m.set(1, 1, c);
                m.set(2, 2, c);
                m.set(2, 1, -s);
                m.set(1, 2, s);
            },
            Axis::YAxis => {
                m.set(0, 0, c);
                m.set(2, 2, c);
                m.set(2, 0, s);
                m.set(0, 2, -s);
            },
            Axis::ZAxis => {
                m.set(0, 0, c);
                m.set(1, 1, c);
                m.set(0, 1, s);
                m.set(1, 0, -s);
            }
        }

        m
    }


}