source/blender/blenlib/BLI_math_matrix_types.hh

@@ -910,6 +910,27 @@ struct MutableMatView
     unroll<NumCol>([&](auto i) { (*this)[i] *= b; });
     return *this;
   }
+
+  /** Vector operators. Need to be redefined to avoid operator priority issue. */
+
+  friend col_type operator*(MutableMatView &a, const row_type &b)
+  {
+    /* This is the reference implementation.
+     * Might be overloaded with vectorized / optimized code. */
+    col_type result(0);
+    unroll<NumCol>([&](auto c) { result += b[c] * a[c]; });
+    return result;
+  }
+
+  /** Multiply by the transposed. */
+  friend row_type operator*(const col_type &a, MutableMatView &b)
+  {
+    /* This is the reference implementation.
+     * Might be overloaded with vectorized / optimized code. */
+    row_type result(0);
+    unroll<NumCol>([&](auto c) { unroll<NumRow>([&](auto r) { result[c] += b[c][r] * a[r]; }); });
+    return result;
+  }
 };
 
 using float2x2 = MatBase<float, 2, 2>;

source/blender/blenlib/tests/BLI_math_matrix_types_test.cc

@@ -388,6 +388,21 @@ TEST(math_matrix_types, ViewMatrixMultiplyOperator)
   EXPECT_EQ(view[1][1], 46);
 }
 
+TEST(math_matrix_types, ViewVectorMultiplyOperator)
+{
+  float4x4 mat = float4x4({1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16});
+  auto view = mat.view<2, 3, 1, 1>();
+
+  float3 result = view * float2(4, 5);
+  EXPECT_EQ(result[0], 74);
+  EXPECT_EQ(result[1], 83);
+  EXPECT_EQ(result[2], 92);
+
+  float2 result2 = float3(1, 2, 3) * view;
+  EXPECT_EQ(result2[0], 44);
+  EXPECT_EQ(result2[1], 68);
+}
+
 TEST(math_matrix_types, ViewMatrixNormalize)
 {
   float4x4 mat = float4x4({1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16});