Added Cargo.lock

matrix/Cargo.lock

@@ -0,0 +1,40 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "approx"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f2a05fd1bd10b2527e20a2cd32d8873d115b8b39fe219ee25f42a8aca6ba278"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
+[[package]]
+name = "matrix"
+version = "0.1.0"
+dependencies = [
+ "approx",
+ "structs",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "structs"
+version = "0.1.0"
+dependencies = [
+ "approx",
+]

matrix/src/lib.rs

@@ -46,6 +46,24 @@ impl Matrix {
     pub fn new_empty_4() -> Matrix {
         Matrix::new_empty(4, 4)
     }
+
+    pub fn identity() -> Matrix {
+        Matrix::new(vec![
+            vec![1.0, 0.0, 0.0, 0.0],
+            vec![0.0, 1.0, 0.0, 0.0],
+            vec![0.0, 0.0, 1.0, 0.0],
+            vec![0.0, 0.0, 0.0, 1.0],
+        ])
+    }
+
+    pub fn transpose(&mut self) {
+        self.matrix = vec![
+            vec![self.matrix[0][0], self.matrix[1][0], self.matrix[2][0], self.matrix[3][0], ],
+            vec![self.matrix[0][1], self.matrix[1][1], self.matrix[2][1], self.matrix[3][1], ],
+            vec![self.matrix[0][2], self.matrix[1][2], self.matrix[2][2], self.matrix[3][2], ],
+            vec![self.matrix[0][3], self.matrix[1][3], self.matrix[2][3], self.matrix[3][3], ],
+        ];
+    }
 }
 
 impl Index<usize> for Matrix {
@@ -277,4 +295,57 @@ mod tests {
 
         assert_eq!(matrix * tuple, expected);
     }
+
+    #[test]
+    fn matrix_by_identity() {
+        let matrix = Matrix::from_array([
+            [0.0, 1.0, 2.0, 4.0,],
+            [1.0, 2.0, 4.0, 8.0,],
+            [2.0, 4.0, 8.0, 16.0],
+            [4.0, 8.0, 16.0, 32.0,]
+        ]);
+
+        let expected = Matrix::from_array([
+            [0.0, 1.0, 2.0, 4.0,],
+            [1.0, 2.0, 4.0, 8.0,],
+            [2.0, 4.0, 8.0, 16.0],
+            [4.0, 8.0, 16.0, 32.0,]
+        ]);
+
+        assert_eq!(matrix * Matrix::identity(), expected);
+    }
+
+    #[test]
+    fn tuple_by_identity() {
+        let t = Tuple::new(1.0, 2.0, 3.0, 4.0);
+        let expected = Tuple::new(1.0, 2.0, 3.0, 4.0);
+
+        assert_eq!(Matrix::identity() * t, expected);
+    }
+
+    #[test]
+    fn transposition() {
+        let mut m = Matrix::from_array([
+            [0.0, 9.0, 3.0, 0.0],
+            [9.0, 8.0, 0.0, 8.0],
+            [1.0, 8.0, 5.0, 3.0],
+            [0.0, 0.0, 5.0, 8.0],
+        ]);
+
+        let expected = Matrix::from_array([
+            [0.0, 9.0, 1.0, 0.0],
+            [9.0, 8.0, 8.0, 0.0],
+            [3.0, 0.0, 5.0, 5.0],
+            [0.0, 8.0, 3.0, 8.0],
+        ]);
+        m.transpose();
+        assert_eq!(m, expected);
+    }
+
+    #[test]
+    fn transpose_identity() {
+        let mut m = Matrix::identity();
+        m.transpose();
+        assert_eq!(m, Matrix::identity());
+    }
 }