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PO2d rotation around point
primarykey
Id
9342374
data
AcceptedAnswerId
9342500
AnswerCount
1
ClosedDate
CommentCount
2
CommunityOwnedDate
CreationDate
2012-02-18T15:15:48.833
FavoriteCount
0
LastActivityDate
2012-02-18T15:37:32.317
LastEditDate
2012-02-18T15:31:33.560
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PostTypeId
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Score
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ViewCount
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LastEditorDisplayName
text
Body
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. This is my code : <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> 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. Anyone good at math sees anything wrong here ?
Tags
<c++><rotation>
Title
2d rotation around point
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PostAcceptedAnswerId
1. PO
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 PostTypePostTypeId
 PTAnswer
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USuser1010005
UserOwnerUserId
1. USuser1010005
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1. This table or related slice is empty.
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1. This table or related slice is empty.
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1. This table or related slice is empty.
PostsParentIdCreationDate
1. PO
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1. This table or related slice is empty.
CommentsPostId
1. COWhy are you multiplying by `deg2rad`? The result of `atan2` is already in radians.
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 PostPostId
 PO2d rotation around point
 UserUserId
 USOliver Charlesworth
2. COThanks good catch now it actually rotates although while the mouse moves away the radius increases.How can i make it so that it stays at selection ?
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 PostPostId
 PO2d rotation around point
 UserUserId
 USuser1010005

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