From e68d14c4d5b4cced62c2148323c38e7f49292bd7 Mon Sep 17 00:00:00 2001
From: Matthew Kosarek <mattkae@protonmail.com>
Date: Thu, 17 Jun 2021 20:44:55 -0400
Subject: Rotating 3d square

---
 shared_cpp/mathlib.h | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

(limited to 'shared_cpp/mathlib.h')

diff --git a/shared_cpp/mathlib.h b/shared_cpp/mathlib.h
index ec0ae87..c922032 100644
--- a/shared_cpp/mathlib.h
+++ b/shared_cpp/mathlib.h
@@ -91,6 +91,10 @@ struct Vector3 {
     float length() {
 		return sqrtf(x * x + y * y + z * z);
 	}
+
+    Vector3 operator+(const Vector3& other) {
+        return { x + other.x, y + other.y, z + other.z };
+    }
 };
 
 struct Vector4 {
@@ -166,6 +170,55 @@ struct Mat4x4 {
         return result;
     }
 
+    Mat4x4 getXRotationMatrix(float angleRadians) {
+        return {
+            { 1, 0, 0, 0,
+              0, cos(angleRadians), -sin(angleRadians), 0,
+              0, sin(angleRadians), cos(angleRadians), 0,
+              0, 0, 0, 1 }
+        };
+    }
+
+    Mat4x4 getYRotationMatrix(float angleRadians) {
+        return {
+            { cos(angleRadians), 0, sin(angleRadians), 0,
+              0, 1, 0, 0,
+              -sin(angleRadians), 0, cos(angleRadians), 0,
+              0, 0, 0, 1 }
+        };
+    }
+
+    Mat4x4 getZRotationMatrix(float angleRadians) {
+        return {
+            { cos(angleRadians), -sin(angleRadians), 0, 0,
+              sin(angleRadians), cos(angleRadians), 0, 0,
+              0, 0, 1, 0,
+              0, 0, 0, 1 }
+        };
+    }
+
+    Mat4x4 rotate(float xRadians, float yRadians, float zRadians) {
+        Mat4x4 result = copy();
+        
+        Mat4x4 rotationMatrix;
+        if (xRadians != 0) {
+            rotationMatrix = getXRotationMatrix(xRadians);
+            result = result * rotationMatrix;
+        }
+
+        if (yRadians != 0) {
+            rotationMatrix = getYRotationMatrix(yRadians);
+            result = result * rotationMatrix;
+        }
+
+        if (zRadians != 0) {
+            rotationMatrix = getZRotationMatrix(zRadians);
+            result = result * rotationMatrix;
+        }
+
+        return result;
+    }
+
     Vector2 multByVec2(Vector2 v) {
         Vector4 vec4 = { v.x, v.y, 0.0, 1.0 };
         return {
@@ -178,6 +231,22 @@ struct Mat4x4 {
         return multByVec2(v);
     }
 
+    Mat4x4 multMat4x4(const Mat4x4& other) {
+        Mat4x4 result;
+        for (int i = 0; i < 4; ++i) {
+            for (int j = 0; j < 4; ++j) {
+                int row = i * 4;
+                result.m[row + j] = m[row + 0] * other.m[0 + j] + m[row + 1] * other.m[4 + j] + m[row + 2] * other.m[8 + j] + m[row + 3] * other.m[12 + j];
+            }
+        }
+
+        return result;
+    }
+
+    Mat4x4 operator*(const Mat4x4& other) {
+        return multMat4x4(other);
+    }
+
     Mat4x4 getOrthographicMatrix(float left, float right, float bottom, float top) {
         Mat4x4 result;
         result.m[0] = 2.0 / (right - left);
-- 
cgit v1.2.1