OpenGL rebuild project start!

2023-04-29 03:06:32 +08:00
parent 7dba067146
commit 4dd3f4f6d1
263 changed files with 51374 additions and 1522 deletions
@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace StgSharp.Math
+{
+    public static unsafe partial class Calc
+    {
+
+        public const float E = 2.718281828f;
+        /// <summary>
+        /// Get the value of E ^ x;
+        /// </summary>
+        /// <param name="x"></param>
+        /// <returns></returns>
+        public static unsafe float Exp(float x)
+        {
+            if (x == 1)
+            {
+                return E;
+            }
+            if (x == 0)
+            {
+                return 1;
+            }
+
+            bool sign = false;
+            if (x<0)
+            {
+                sign = true;
+                x = -x;
+            }
+
+            float z = x , t;
+            if (x<0.5f)
+            {
+                t = 1.0f + x * (
+                    1.0f + x * (
+                    0.5f + x * (
+                    0.1666666667f + x * (
+                    0.0416666666667f + x *
+                    8.333333333e-3f))));
+            }
+            else
+            {
+                uint zBit = *(uint*)&z;
+                uint zBitAbs = zBit & 0b_0111_1111_1111_1111_1111_1111_1111_1111;
+                uint uintm = (zBitAbs >> 23);
+                int m = (*(int*)&uintm) - 126;
+
+
+                uint nBit = (zBitAbs & 0b_0000_0000_0111_1111_1111_1111_1111_1111)
+                    + 0b_0011_1111_0000_0000_0000_0000_0000_0000;
+                float n = *(float*)&nBit - 1;
+
+                t = 2.718281828f + n * (
+                    2.718281828f + n * (
+                    1.359140914f + n * (
+                    0.4530469714f + n * (
+                    0.1132617429f + n *
+                    0.02265234857f))));
+
+                for (int i = 0; i < m; i++)
+                {
+                    t = t * t;
+                }
+            }
+
+            if (sign)
+            {
+                t = 1 / t;
+            }
+            return t;
+        }
+    }
+}