1 files changed, 73 insertions, 0 deletions
diff --git a/src/util/mini_math.h b/src/util/mini_math.h
index 7314933..a1b1363 100644
--- a/src/util/mini_math.h
+++ b/src/util/mini_math.h
@@ -137,6 +137,79 @@ struct mat4 {
   float m[16] = {1, 0, 0, 0, 0, 1, 0, 0,
                  0, 0, 1, 0, 0, 0, 0, 1}; // Identity (Column-Major)
 
+  // Array access
+  float& operator[](int i) {
+    return m[i];
+  }
+  const float& operator[](int i) const {
+    return m[i];
+  }
+
+  // Matrix multiplication
+  mat4 operator*(const mat4& r) const {
+    mat4 res;
+    for (int col = 0; col < 4; ++col) {
+      for (int row = 0; row < 4; ++row) {
+        float sum = 0.0f;
+        for (int k = 0; k < 4; ++k) {
+          sum += m[k * 4 + row] * r.m[col * 4 + k];
+        }
+        res.m[col * 4 + row] = sum;
+      }
+    }
+    return res;
+  }
+
+  // Vector multiplication (Transform)
+  vec4 operator*(const vec4& v) const {
+    vec4 res;
+    for (int row = 0; row < 4; ++row) {
+      res.v[row] = m[row] * v.x + m[row + 4] * v.y + m[row + 8] * v.z +
+                   m[row + 12] * v.w;
+    }
+    return res;
+  }
+
+  // Translation
+  static mat4 translate(vec3 t) {
+    mat4 r; // Identity
+    r.m[12] = t.x;
+    r.m[13] = t.y;
+    r.m[14] = t.z;
+    return r;
+  }
+
+  // Scaling
+  static mat4 scale(vec3 s) {
+    mat4 r; // Identity
+    r.m[0] = s.x;
+    r.m[5] = s.y;
+    r.m[10] = s.z;
+    return r;
+  }
+
+  // Rotation (Axis-Angle)
+  static mat4 rotate(vec3 axis, float angle) {
+    vec3 a = axis.normalize();
+    float s = std::sin(angle);
+    float c = std::cos(angle);
+    float oc = 1.0f - c;
+
+    mat4 r;
+    r.m[0] = oc * a.x * a.x + c;
+    r.m[1] = oc * a.x * a.y + a.z * s;
+    r.m[2] = oc * a.x * a.z - a.y * s;
+
+    r.m[4] = oc * a.x * a.y - a.z * s;
+    r.m[5] = oc * a.y * a.y + c;
+    r.m[6] = oc * a.y * a.z + a.x * s;
+
+    r.m[8] = oc * a.x * a.z + a.y * s;
+    r.m[9] = oc * a.y * a.z - a.x * s;
+    r.m[10] = oc * a.z * a.z + c;
+    return r;
+  }
+
   static mat4 perspective(float fov, float asp, float n, float f) {
     mat4 r = {};
     float t = 1.0f / std::tan(fov * 0.5f);