Determinants

src/java/org/lwjgl/vector/Matrix3f.java

@@ -309,6 +309,17 @@ public class Matrix3f {
 
 	}
 
+	/**
+	 * @return the determinant of the matrix
+	 */
+	public float determinant() {
+		float f =
+			m00 * (m11 * m22 - m12 * m21)
+				+ m01 * (m12 * m20 - m10 * m22)
+				+ m02 * (m10 * m21 - m11 * m20);
+		return f;
+	}
+
 	/**
 	 * Invert this matrix
 	 * @return this

src/java/org/lwjgl/vector/Matrix4f.java

@@ -399,6 +399,34 @@ public class Matrix4f {
 		return dest;
 	}
 
+	/**
+	 * @return the determinant of the matrix
+	 */
+	public float determinant() {
+		float f =
+			m00
+				* ((m11 * m22 * m33 + m12 * m23 * m31 + m13 * m21 * m32)
+					- m13 * m22 * m31
+					- m11 * m23 * m32
+					- m12 * m21 * m33);
+		f -= m01
+			* ((m10 * m22 * m33 + m12 * m23 * m30 + m13 * m20 * m32)
+				- m13 * m22 * m30
+				- m10 * m23 * m32
+				- m12 * m20 * m33);
+		f += m02
+			* ((m10 * m21 * m33 + m11 * m23 * m30 + m13 * m20 * m31)
+				- m13 * m21 * m30
+				- m10 * m23 * m31
+				- m11 * m20 * m33);
+		f -= m03
+			* ((m10 * m21 * m32 + m11 * m22 * m30 + m12 * m20 * m31)
+				- m12 * m21 * m30
+				- m10 * m22 * m31
+				- m11 * m20 * m32);
+		return f;
+	}
+		
 
 	/**
 	 * Invert this matrix