daily update on 20230320 by nitload youmu

2023-03-20 01:45:49 +08:00
parent 167e33a3dd
commit db2ca36fd7
100 changed files with 1211 additions and 746 deletions
@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StgSharp.Math
+{
+    public static unsafe partial class Vector
+    {
+
+        public static float Det(matrix2x2 array)
+        {
+            return Cross(array.row1,array.row2);
+        }
+
+        public static unsafe float Det(matrix3x3 array)
+        {
+            float* p = &array.row1.X;
+
+            matrix2x2 matrix1 = new matrix2x2(
+                *(p + 4), *(p + 5),
+                *(p + 7), *(p + 8)
+                );
+            matrix2x2 matrix2 = new matrix2x2(
+                *(p + 3), *(p + 5),
+                *(p + 6), *(p + 8)
+                );
+            matrix2x2 matrix3 = new matrix2x2(
+                *(p + 3), *(p + 4),
+                *(p + 6), *(p + 7)
+                );
+
+            return 
+                *p * Det(matrix1)
+                - *(p + 1) * Det(matrix2)
+                + *(p + 2) * Det(matrix3)
+                ;
+        }
+    }
+}