Math lib: added matrix-scalar multiplication operators

Common/interface/BasicMath.hpp

@@ -889,6 +889,23 @@ template <class T> struct Matrix2x2
     }
 };
 
+template <typename T>
+inline constexpr Matrix2x2<T> operator*(const Matrix2x2<T>& Mat, T s)
+{
+    // clang-format off
+    return 
+    {
+        Mat._11 * s, Mat._12 * s,
+        Mat._21 * s, Mat._22 * s
+    };
+    // clang-format on
+}
+
+template <typename T>
+inline constexpr Matrix2x2<T> operator*(T s, const Matrix2x2<T>& Mat)
+{
+    return Mat * s;
+}
 
 template <class T> struct Matrix3x3
 {
@@ -1169,6 +1186,26 @@ template <class T> struct Matrix3x3
     }
 };
 
+template <typename T>
+inline constexpr Matrix3x3<T> operator*(const Matrix3x3<T>& Mat, T s)
+{
+    // clang-format off
+    return 
+    {
+        Mat._11 * s, Mat._12 * s, Mat._13 * s,
+        Mat._21 * s, Mat._22 * s, Mat._23 * s,
+        Mat._31 * s, Mat._32 * s, Mat._33 * s
+    };
+    // clang-format on
+}
+
+template <typename T>
+inline constexpr Matrix3x3<T> operator*(T s, const Matrix3x3<T>& Mat)
+{
+    return Mat * s;
+}
+
+
 template <class T> struct Matrix4x4
 {
     union
@@ -1730,6 +1767,26 @@ template <class T> struct Matrix4x4
     }
 };
 
+template <typename T>
+inline constexpr Matrix4x4<T> operator*(const Matrix4x4<T>& Mat, T s)
+{
+    // clang-format off
+    return 
+    {
+        Mat._11 * s, Mat._12 * s, Mat._13 * s, Mat._14 * s,
+        Mat._21 * s, Mat._22 * s, Mat._23 * s, Mat._24 * s,
+        Mat._31 * s, Mat._32 * s, Mat._33 * s, Mat._34 * s,
+        Mat._41 * s, Mat._42 * s, Mat._43 * s, Mat._44 * s
+    };
+    // clang-format on
+}
+
+template <typename T>
+inline constexpr Matrix4x4<T> operator*(T s, const Matrix4x4<T>& Mat)
+{
+    return Mat * s;
+}
+
 // Template Vector Operations
 
 
@@ -2003,6 +2060,10 @@ using double4x4 = Matrix4x4<double>;
 using double3x3 = Matrix3x3<double>;
 using double2x2 = Matrix2x2<double>;
 
+using int4x4 = Matrix4x4<Int32>;
+using int3x3 = Matrix3x3<Int32>;
+using int2x2 = Matrix2x2<Int32>;
+
 template <typename T = float>
 struct Quaternion
 {

Tests/DiligentCoreTest/src/Common/MathLibTest.cpp

@@ -1318,6 +1318,61 @@ TEST(Common_BasicMath, HighPrecisionCross)
     }
 }
 
+
+TEST(Common_BasicMath, MatrixScalarMultiply)
+{
+    // clang-format off
+    EXPECT_EQ(float2x2(1, 2,
+                       3, 4) * 2.f,
+              float2x2(2, 4,
+                       6, 8)
+              );
+    EXPECT_EQ(float3x3(1, 2, 3,
+                       4, 5, 6,
+                       7, 8, 9) * 2.f,
+              float3x3( 2,  4,  6,
+                        8, 10, 12,
+                       14, 16, 18)
+              );
+    EXPECT_EQ(float4x4( 1,  2,  3,  4,
+                        5,  6,  7,  8,
+                        9, 10 ,11, 12,
+                       13, 14, 15, 16) * 2.f,
+              float4x4( 2,  4,  6,  8,
+                       10, 12, 14, 16,
+                       18, 20 ,22, 24,
+                       26, 28, 30, 32)
+              );
+    // clang-format on
+}
+
+TEST(Common_BasicMath, ScalarMatrixMultiply)
+{
+    // clang-format off
+    EXPECT_EQ(2 * int2x2(1, 2,
+                         3, 4),
+              int2x2(2, 4,
+                     6, 8)
+              );
+    EXPECT_EQ(2 * int3x3(1, 2, 3,
+                         4, 5, 6,
+                         7, 8, 9),
+              int3x3( 2,  4,  6,
+                      8, 10, 12,
+                     14, 16, 18)
+              );
+    EXPECT_EQ(2 * int4x4( 1,  2,  3,  4,
+                          5,  6,  7,  8,
+                          9, 10 ,11, 12,
+                         13, 14, 15, 16),
+              int4x4( 2,  4,  6,  8,
+                     10, 12, 14, 16,
+                     18, 20 ,22, 24,
+                     26, 28, 30, 32)
+              );
+    // clang-format on
+}
+
 TEST(Common_AdvancedMath, Planes)
 {
     Plane3D plane = {};