Added proper hit test with rotation and pivoting

include/app/app.h

@@ -15,6 +15,7 @@ struct Element {
   Type type;
   Vec2<float> position = {0, 0};
   float rotation = 0;
+  Vec2<float> pivot = {0, 0};
   Vec2<float> scale = {1, 1};
   float alpha = 1.0f;
   float z = 0;
@@ -24,7 +25,7 @@ struct Element {
   Element(Type type) : type(type) {}
   virtual ~Element() = default;
   virtual void render(Window &window, uint64_t abs_time) = 0;
-  virtual Vec2<float> size(Window *window) = 0;
+  virtual Vec2<float> size() = 0;
 
   void click() {
     on_click.call();
@@ -43,11 +44,11 @@ struct EImage : Element {
       animation_pool.release(animation_id);
   }
 
-  Vec2<float> size(Window *window) override {
+  Vec2<float> size() override {
     Animation &animation = *animation_pool[animation_id];
     if (animation.frames.empty())
       return {0, 0};
-    return window->get_image_size(animation.frames[0]);
+    return window.get_image_size(animation.frames[0]);
   }
 
   void render(Window &window, uint64_t abs_time) override {
@@ -55,7 +56,7 @@ struct EImage : Element {
     if (animation.frames.empty())
       return;
     int frame_index = (int)((abs_time * animation.frame_rate) / 1e9) % animation.frames.size();
-    window.draw(animation.frames[frame_index], position, z, rotation, scale, alpha);
+    window.draw(animation.frames[frame_index], position, z, rotation, pivot, scale, alpha);
   }
 };
 
@@ -86,10 +87,10 @@ struct EText : Element {
     last_key = UINT16_MAX;
   }
 
-  Vec2<float> size(Window *window) override {
+  Vec2<float> size() override {
     if (text_id == UINT64_MAX)
       return {0, 0};
-    return window->get_text_size(text_id);
+    return window.get_text_size(text_id);
   };
 
   void render(Window &window, uint64_t) override {
@@ -106,7 +107,7 @@ struct EText : Element {
       last_key = key;
       last_color = color;
     }
-    window.write(text_id, position, z, rotation, scale, alpha);
+    window.write(text_id, position, z, rotation, pivot, scale, alpha);
   }
 
 private:
@@ -119,14 +120,14 @@ private:
 struct ERect : Element {
   Vec2<float> shape = {0, 0};
   Color color = {255, 255, 255};
-  Vec2<float> size(Window *) override {
+  Vec2<float> size() override {
     return shape;
   };
 
   ERect(Vec2<float> shape, Color color) : Element(Type::RECT), shape(shape), color(color) {}
 
   void render(Window &window, uint64_t) override {
-    window.draw_rect(Rect::from_size(position, shape), color, z, rotation, scale, alpha);
+    window.draw_rect(Rect::from(position, shape), color, z, rotation, pivot, scale, alpha);
   }
 };
 
@@ -177,16 +178,19 @@ struct Scene {
       element_pool[id]->click();
   }
 
-#warning "This does not take rotation into account \
-reference and use reverse-transform on point then AABB check instead"
+  void render(Window &window, uint64_t abs_time) {
+    for (const uint64_t &e : element_ids)
+      element_pool[e]->render(window, abs_time);
+  }
+
   std::vector<uint64_t> elements_at(Vec2<float> position) {
     std::vector<uint64_t> result;
 
     for (auto it = element_ids.rbegin(); it != element_ids.rend(); ++it) {
       Element *e = element_pool[*it];
-      Vec2<float> size = e->size(&window);
-      Rect rect = Rect::from_size(e->position, size * e->scale);
-      if (rect.contains(position)) {
+      Vec2<float> size = e->size();
+      Rect rect = Rect::from(size);
+      if (rect.contains(world_to_local(position, e))) {
         result.push_back(*it);
         if (e->click_through)
           continue;
@@ -198,9 +202,25 @@ reference and use reverse-transform on point then AABB check instead"
     return result;
   }
 
-  void render(Window &window, uint64_t abs_time) {
-    for (const uint64_t &e : element_ids)
-      element_pool[e]->render(window, abs_time);
+  Vec2<float> world_to_local(Vec2<float> p, Element *e) {
+    Vec2<float> size = e->size();
+    Vec2<float> pivot = e->pivot * size * e->scale;
+    p = p - e->position;
+
+    float rad = -e->rotation * (M_PI / 180.0f);
+    float c = cos(rad);
+    float s = sin(rad);
+
+    p = p - pivot;
+    p = {
+      p.x * c - p.y * s,
+      p.x * s + p.y * c
+    };
+
+    p = p + pivot;
+    p = p / e->scale;
+
+    return p;
   }
 };