Cocos2dx coordinate system details

1. In cocos2dx, the following coordinate systems are supported:

● Screen coordinate system: the origin is in the upper left corner, the X axis is right, and the Y axis is down. (For example, when processing a touch event, the coordinates in the CCTouch object are the screen coordinate system)

● OpenGL coordinate system: the origin is in the lower left corner, the X axis is right, and the Y axis is up. (For example, the setPosition function call of the CCNode class is the coordinate system)

● World coordinate system: refers to the coordinate system (0, 0) relative to the whole screen, which is the lower left corner of the screen.

● Local coordinate system: Coordinates relative to the parent object.

2. AnchorPoint)

● In one sentence, we can refer to the anchor as nailing a piece of paper or photo to the point on the wall.

● The value range of x and y of the anchor is [0, 1.

● The default anchor of Sprite is (0.5, 0.5). The anchor is not ignored by default.

Virtual bool isIgnoreAnchorPointForPosition (); // false is returned by default.

● For other nodes such as CCLayer and CCSense, the default value of the anchor is (0, 0). The default value is ignore anchor.

Virtual bool isIgnoreAnchorPointForPosition (); // returns true by default.

Therefore, if you want to set the anchor in CCLayer and CCSense, you need to set the following

CCLayer * layer1 = CCLayerColor: create (ccc4 (0,255, 300,200),); addChild (layer1); layer1-> ignoreAnchorPointForPosition (false); // you can specify not to ignore the anchor, at this time, the anchorpoint will change to the default (0.5, 0.5) layer1-> setAnchorPoint (ccp (); // then set the custom anchor here

<喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4KPHA + PGJyPgo8L3A + release + MyDX + release + rPuL3iys3I58/Co6zTprjD0tG + release "brush: java;"> CCSprite * sprite1 = CCSprite :: create ("CloseNormal.png"); CCLOG ("sprite1 = (% f, % f)", sprite1-> getContentSize (). width, sprite1-> getContentSize (). height); sprite1-> setAnchorPoint (ccp (1, 1); sprite1-> setPosition (ccp (20, 40); CCSprite * sprite2 = CCSprite: create ("CloseNormal.png "); sprite2-> setPosition (ccp (-5,-20); sprite2-> setAnchorPoint (ccp (1, 1 )); CCPoint point1 = sprite1-> convertToNodeSpace (sprite2-> getPosition (); // use the lower left corner of sprite1 as the reference point (0, 0) to locate the coordinates of the sprite2 anchpoint, return CCPoint point2 = sprite1-> convertToWorldSpace (sprite2-> getPosition (); // locate (-5, 20) with the reference point () in the lower left corner of sprite1) the vertex is the coordinate of the sprite2 anchor, and the CCPoint point3 = sprite1-> convertToNodeSpaceAR (sprite2-> getPosition () is returned. // use the sprite1 anchor as the reference point (0, 0 ), locate the position of the sprite2 anchor and return CCPoint point4 = sprite1-> convertToWorldSpaceAR (sprite2-> getPosition (); // use the sprite1 anchor as the reference point (0, 0 ), locate (-5, 20) The point is the sprite2 anchor coordinate and return CCLOG ("point1 = (% f, % f)", point1.x, point1.y ); CCLOG ("point2 = (% f, % f)", point2.x, point2.y); CCLOG ("point3 = (% f, % f)", point3.x, point3.y ); CCLOG ("point4 = (% f, % f)", point4.x, point4.y );

The output result is as follows:

Sprite1 = (40.000000, 40.000000) (image size)
Point1 = (15.000000,-20.000000)
Point2 = (-25.000000,-20.000000)
Point3 = (-25.000000,-60.000000)
Point4 = (15.000000, 20.000000)