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PO2d rotation around point
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copied!<p>I'm trying to add some features into my editor that allow to the user things like dragging a selected item to a given direction although i've ran into a damn issue.</p> <p>This is my code :</p> <pre><code>//Origin double objectx = selection->getX(); double objecty = selection->getY(); //Point double pointerx = input->getMouseX(); double pointery = input->getMouseY(); //Displacement double displacementx = fabs(pointerx - objectx); double displacementy = fabs(pointery - objecty); //Angle double angle = atan2(displacementy,displacementx); //Point double pointx = displacementx * cosf(angle) + displacementy * sinf(angle); double pointy = displacementy * cosf(angle) - displacementx * sinf(angle); //Final position double fx = objectx + pointx; double fy = objecty + pointy; //Save alpha const bool alpha = graphics->getAlpha(); //Draw selection graphics->setAlpha(false); graphics->color(selection->getColor()); graphics->renderQd(selection->getBitmap(), CRect(objectx, objecty, selection->getWidth(), selection->getHeight())); //Draw pointer around selection graphics->setAlpha(true); graphics->color(editor::ssImg[0]->getColor()); graphics->renderQd(editor::ssImg[0]->getBitmap(), CRect(objectx + pointx, objecty + pointy, editor::ssImg[0]->getWidth(), editor::ssImg[0]->getHeight())); //Restore alpha graphics->setAlpha(alpha); </code></pre> <p>The exact issue is that the selection pointer doesn't follow mouse's rotation only but its actually at mouse's position(!). The wanted behaviour is a pointer locked at selection's offset but pointing to the mouse's angle.</p> <p>Anyone good at math sees anything wrong here ?</p>

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