Simplify

calculation of canvas position based on the cursor position and expected rotation

inc/App.hpp

@@ -16,7 +16,6 @@ private:
   int pos = 0;
   int screenWidth, screenHeight;
   std::vector<Canvas> canvases;
-  Vector2 center;
   float rotation = 0.0f;
   Rectangle destB;
   Rectangle destA;

inc/Math.hpp

@@ -1,5 +1,4 @@
 #include "raylib.h"
 
 Color ColorLerp(Color c1, Color c2, float amount);
-Vector2 calculateVector(float rotation, float offSet, float len);
-Rectangle calculateRotatedRectangle(Vector2 center, float rotation, float width, float height);
+Vector2 calculateVector(float rotation, float offSet, float len);

src/App.cpp

@@ -18,9 +18,8 @@ void App::init(int screenWidth, int screenHeight)
     canvas.newGen();
   }
 
-  center = {(float)screenWidth / 2, (float)screenHeight / 2};
-  float rotation = 0.0f;
-  destA = calculateRotatedRectangle(center, rotation, screenWidth, screenWidth);
+  float posY = (screenHeight - screenWidth) / 2;
+  destA = {0, posY, (float)screenWidth, (float)screenWidth};
   destB = destA;
 }
 
@@ -29,24 +28,19 @@ void App::update()
   if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT))
   {
     mouseStart = GetMousePosition();
-    len = Vector2Distance(mouseStart, center);
-    ofset = std::atan2(center.x - mouseStart.x, center.y - mouseStart.y);
+    len = Vector2Distance(mouseStart, {destB.x, destB.y});
+    ofset = std::atan2(destB.x - mouseStart.x, destB.y - mouseStart.y);
   }
 
   if (IsMouseButtonDown(MOUSE_BUTTON_LEFT))
   {
     Vector2 mousePosition = GetMousePosition();
-
     float dist = mousePosition.x - mouseStart.x;
-
     float l = dist / screenWidth;
     rotation = Lerp(45.0f, -45.0f, (l + 1) / 2);
-
     Vector2 newCenter = calculateVector(rotation, ofset, len);
-    newCenter.x += mousePosition.x;
-    newCenter.y += mousePosition.y;
-
-    destA = calculateRotatedRectangle(newCenter, rotation, screenWidth, screenWidth);
+    destA.x = newCenter.x + mousePosition.x;
+    destA.y = newCenter.y + mousePosition.y;
   }
 
   if (IsMouseButtonReleased(MOUSE_BUTTON_LEFT))

src/Math.cpp

@@ -19,20 +19,4 @@ Vector2 calculateVector(float rotation, float offSet, float len)
   return {
       .x = len * std::sin(angle),
       .y = len * std::cos(angle)};
-}
-
-Rectangle calculateRotatedRectangle(Vector2 center, float rotation, float width, float height)
-{
-  Rectangle ret = {0, 0, width, height};
-
-  width /= 2;                                                      // a
-  height /= 2;                                                     // b
-  float len = std::sqrt(std::pow(width, 2) + std::pow(height, 2)); // c
-  float offSet = std::atan2(width, height);                        // add angle alfa
-
-  Vector2 vec = calculateVector(rotation + 180.0f, offSet, len);
-
-  ret.x = vec.x + center.x;
-  ret.y = vec.y + center.y;
-  return ret;
 }