daily update on 20230228 by nitload youmu

2023-03-01 00:04:40 +08:00
parent 035fb9a432
commit d09105c9c1
49 changed files with 258 additions and 117 deletions
@@ -12,9 +12,28 @@ namespace StgSharp.Math
            return Cross(array.row0,array.row1);
        }

-        public static float Det(Array3x3 array)
+        public static unsafe float Det(Array3x3 array)
        {
-            return 0;
+            float* p = &array.row1.X;
+
+            Array2x2 array1 = new Array2x2(
+                *(p + 4), *(p + 5),
+                *(p + 7), *(p + 8)
+                );
+            Array2x2 array2 = new Array2x2(
+                *(p + 3), *(p + 5),
+                *(p + 6), *(p + 8)
+                );
+            Array2x2 array3 = new Array2x2(
+                *(p + 3), *(p + 4),
+                *(p + 6), *(p + 7)
+                );
+
+            return 
+                *p * Det(array1)
+                - *(p + 1) * Det(array2)
+                + *(p + 2) * Det(array3)
+                ;
        }
    }
 }