From c36d05d5aed2f8f7c6342b174692146e2d11c386 Mon Sep 17 00:00:00 2001
From: Matthew Kosarek <mattkae@protonmail.com>
Date: Mon, 22 Mar 2021 20:54:51 -0400
Subject: Refactored frontend, beginnings of general cpp layer, and beginning
 roadmap

---
 frontend/shared_cpp/mathlib.h | 130 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 frontend/shared_cpp/mathlib.h

(limited to 'frontend/shared_cpp/mathlib.h')

diff --git a/frontend/shared_cpp/mathlib.h b/frontend/shared_cpp/mathlib.h
new file mode 100644
index 0000000..93ddbbd
--- /dev/null
+++ b/frontend/shared_cpp/mathlib.h
@@ -0,0 +1,130 @@
+#pragma once
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+struct Vector2 {
+    float x = 0;
+    float y = 0;
+
+    Vector2 operator+(Vector2 other) {
+        return { x + other.x, y + other.y };
+    }
+
+    Vector2 operator-(Vector2 other) {
+        return { x - other.x, y - other.y };
+    }
+
+    Vector2 operator*(float s) {
+        return { x * s, y * s };
+    }
+
+    float dot(Vector2 other) {
+        return x * other.x + y * other.y;
+    }
+
+    float length() {
+        return sqrtf(x * x + y * y);
+    }
+
+    Vector2 normalize() {
+        float len = length();
+        float inverseLength = len == 0 ? 1.0 : 1.0 / len;
+
+        return { x * inverseLength, y * inverseLength };
+    }
+
+    Vector2 negate() {
+        return { -x, -y };
+    }
+
+    Vector2 getPerp() {
+        return { -y, x };
+    }
+};
+
+struct Vector3 {
+    float x = 0.f;
+    float y = 0.f;
+    float z = 0.f;
+};
+
+struct Vector4 {
+    float x = 0.f;
+    float y = 0.f;
+    float z = 0.f;
+    float w = 0.f;
+};
+
+struct Mat4x4 {
+    float m[16] = {
+        1, 0, 0, 0,
+        0, 1, 0, 0,
+        0, 0, 1, 0,
+        0, 0, 0, 1
+    };
+
+    Mat4x4 copy() {
+        Mat4x4 result;
+        memcpy(result.m, m, sizeof(float) * 16);
+        return result;
+    }
+
+    Mat4x4 scale(Vector3 v) {
+        Mat4x4 result = copy();
+        result.m[0] = result.m[0] * v.x;
+        result.m[5] = result.m[5] *v.y;
+        result.m[10] = result.m[10] * v.z;
+        return result;
+    }
+
+    Mat4x4 translate(Vector3 v) {
+        Mat4x4 result = copy();
+        result.m[12] += v.x;
+        result.m[13] += v.y;
+        result.m[14] += v.z;
+        return result;
+    }
+
+	Mat4x4 translateByVec2(Vector2 v) {
+        Mat4x4 result = copy();
+        result.m[12] += v.x;
+        result.m[13] += v.y;
+        return result;
+    }
+
+    Mat4x4 rotate2D(float angle) {
+        Mat4x4 result = copy();
+        result.m[0] = cos(angle);
+        result.m[1] = -sin(angle);
+        result.m[4] = sin(angle);
+        result.m[5] = cos(angle);
+        return result;
+    }
+
+    Vector2 multByVec2(Vector2 v) {
+        Vector4 vec4 = { v.x, v.y, 0.0, 1.0 };
+        return {
+            vec4.x * m[0] + vec4.y * m[4] + vec4.z * m[8] + vec4.w * m[12],
+            vec4.x * m[1] + vec4.y * m[5] + vec4.z * m[9] + vec4.w * m[13]
+        };
+    }
+
+    Mat4x4 getOrthographicMatrix(float left, float right, float bottom, float top) {
+        Mat4x4 result;
+        result.m[0] = 2.0 / (right - left);
+        result.m[5] = 2.0 / (top - bottom);
+        result.m[10] = 1.0;
+        result.m[12] = -(right + left) / (right - left);
+        result.m[13] = -(top + bottom) / (top - bottom);
+        return result;
+    }
+
+	void print() {
+		printf("[ ");
+		for (int idx = 0; idx < 16; idx++) {
+			printf("%d, ", idx);
+		}
+		printf(" ]\n");
+	}
+};
-- 
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