Add example of rotation

random/rotating.cpp

@@ -0,0 +1,114 @@
+#include <iostream>
+#include <cmath>
+#include <array>
+
+#include <raylib.h>
+#include <raymath.h>
+
+int screenWidth = 600;
+int screenHeight = 800;
+
+int pos = 0;
+Vector2 mouseStart;
+float len;
+float ofset;
+bool validHit = false;
+
+float rotation = 0.0f;
+Rectangle destB;
+Rectangle destA;
+
+std::array<RenderTexture2D, 2> canvasTexure = {0};
+
+void init()
+{
+  for (size_t i = 0; i < canvasTexure.size(); i++)
+  {
+    canvasTexure[i] = LoadRenderTexture(screenWidth, screenWidth);
+  }
+
+  BeginTextureMode(canvasTexure[0]);
+  ClearBackground(WHITE);
+  EndTextureMode();
+
+  BeginTextureMode(canvasTexure[1]);
+  ClearBackground(BLUE);
+  EndTextureMode();
+
+  float posY = (screenHeight - screenWidth) / 2.0f;
+  destA = {0, posY, (float)screenWidth, (float)screenWidth};
+  destB = destA;
+}
+
+Vector2 CalculateVector(float rotation, float offSet, float len)
+{
+  float angle = ((rotation)*PI) / 180.0f;
+  angle += offSet;
+  return {
+      .x = len * std::sin(angle),
+      .y = len * std::cos(angle)};
+}
+
+void update()
+{
+  if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT))
+  {
+    mouseStart = GetMousePosition();
+    validHit = CheckCollisionPointRec(mouseStart, destA);
+    len = Vector2Distance(mouseStart, {destB.x, destB.y});
+    ofset = std::atan2(destB.x - mouseStart.x, destB.y - mouseStart.y);
+  }
+
+  if (IsMouseButtonDown(MOUSE_BUTTON_LEFT) && validHit)
+  {
+    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);
+    destA.x = newCenter.x + mousePosition.x;
+    destA.y = newCenter.y + mousePosition.y;
+  }
+
+  if (IsMouseButtonReleased(MOUSE_BUTTON_LEFT) && validHit)
+  {
+    pos = 1 - pos;
+    rotation = 0.0f;
+    destA = destB;
+  }
+}
+
+void drawTexureWithRotation(RenderTexture2D &target, Rectangle &dest, float rotation)
+{
+  Rectangle source = {0, 0, (float)target.texture.width, (float)-target.texture.height};
+  Vector2 origin = {0.0f, 0.0f};
+  rotation = 360 - rotation;
+  DrawTexturePro(target.texture, source, dest, origin, rotation, WHITE);
+}
+
+void draw()
+{
+  ClearBackground(RED);
+  drawTexureWithRotation(canvasTexure[pos], destB, 0.0f);
+  drawTexureWithRotation(canvasTexure[1 - pos], destA, rotation);
+}
+
+int main(int argc, char const *argv[])
+{
+  char name[] = "treender";
+  int screenWidth = 600;
+  int screenHeight = 800;
+  InitWindow(screenWidth, screenHeight, name);
+  SetTargetFPS(60);
+  init();
+  while (!WindowShouldClose())
+  {
+    update();
+    BeginDrawing();
+    draw();
+    EndDrawing();
+  }
+
+  CloseWindow();
+  return 0;
+}