After many hours of struggle i was finally able to draw a object, but got stuck when it came to rotating. I am trying to make a rotation around the y-axis, but i cannot seem to make the rotation smooth in any way. Its pretty much jumping around. There might be some bits and pieces of uneccessary in between hence i used a template.
- (void)update
{
float aspect = fabsf(self.view.bounds.size.width / self.view.bounds.size.height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 0.1f, 100.0f);
self.effect.transform.projectionMatrix = projectionMatrix;
GLKMatrix4 baseModelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -4.0f);
// Compute the model view matrix for the object rendered with ES2
GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 0.0f);
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, startPoint.y, 0.0f, 1.0f, 0.0f);
dx = dy = 0;
modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix);
_normalMatrix = GLKMatrix3InvertAndTranspose(GLKMatrix4GetMatrix3(modelViewMatrix), NULL);
_modelViewProjectionMatrix = GLKMatrix4Multiply(projectionMatrix, modelViewMatrix);
_rotation += self.timeSinceLastUpdate * 0.5f;
}
And my touch behaviours:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
startPoint = [touch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self.view];
dx = point.y - startPoint.y;
dy = point.x - startPoint.x;
startPoint = point;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
}
Thanks in advance.
going through the below link of apple library it can be solve your problem
[http://developer.apple.com/library/ios/#samplecode/GLSprite/Introduction/Intro.html#//apple_ref/doc/uid/DTS40007325
Related
I am trying to make a sprite rotate with one finger touch. Honestly, i have no idea how to do it, new to spriteKit.
Any ideas?
This would rotate the sprite to where you touch using an action. If you'd want it to rotate while dragging the finger. You should remove the action and do the calculation on the touchesMoved: instead.
-(void)didMoveToView:(SKView *)view {
sprite = [SKSpriteNode spriteNodeWithImageNamed:#"Spaceship"];
sprite.xScale = 0.5;
sprite.yScale = 0.5;
sprite.position = CGPointMake(self.frame.size.width / 2, self.frame.size.height/2);
[self addChild:sprite];
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
float dY = sprite.position.y - location.y;
float dX = sprite.position.x - location.x;
float angle = atan2f(dY, dX) + 1.571f;
[sprite runAction:[SKAction rotateToAngle:angle duration:0.5 shortestUnitArc:YES]];
return;
}
}
Alternatively: (Remember to remove the code from the touchesBegan:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
for (UITouch *touch in touches) {
CGPoint location = [touch locationInNode:self];
float dY = sprite.position.y - location.y;
float dX = sprite.position.x - location.x;
float angle = (atan2f(dY, dX)) + 1.571f;
sprite.zRotation = angle;
}
}
I've created a 200x200 circle in a custom UIView. I am using the following script to move the view object around the screen on the iPad.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:self.view];
if([touch view] == newShape)
{
newShape.center = currentPoint;
}
[self.view setNeedsDisplay];
}
Everything works fine, I can move the circle anywhere on the screen. However, if I don't touch dead center on the circle object, it jumps slightly. By reading the code, this is quite obvious because newShape.center is being set to wherever the touch happens and ultimately snapping quickly to that position.
I'm looking for a way to move an object without snapping to the touch position. I'm thinking I would use xy coordinates to achieve this, but I'm not sure how to implement it.
Thanks!
Declare CGPoint prevPos; in .h file.
Here my view is _rectView.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:self.view];
prevPos = currentPoint;
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentPoint = [touch locationInView:self.view];
if([touch view] == _rectView)
{
float delX = currentPoint.x - prevPos.x;
float delY = currentPoint.y - prevPos.y;
CGPoint np = CGPointMake(_rectView.frame.origin.x+delX, _rectView.frame.origin.y+delY);
//_rect.center = np;
CGRect fr = _rectView.frame;
fr.origin = np;
_rectView.frame = fr;
}
//[self.view setNeedsDisplay];
prevPos = currentPoint;
}
Use the above code. You will not get that 'jump' effect.
An obvious way to do it is to store the offset of the touch from the shape's center in -touchesBegan:withEvent: and apply the offset in -touchesMoved:withEvent:.
I am building a brush app, it's almost finish and what i did was just a basic brush/drawing tool. I want to give it a more brush-like feel because in my current output it has angles and it doesn't look like a real brush ink.
here's my code:
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
touchSwiped = YES;
UITouch *touch = [touches anyObject];
currentTouch = [touch locationInView:self.view];
currentTouch.y -= 20;
UIGraphicsBeginImageContext(self.view.frame.size);
[touchDraw.image drawInRect:CGRectMake(0, 0, touchDraw.frame.size.width, touchDraw.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 35.0);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), redAmt, blueAmt, greenAmt, 1.0);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), endingPoint.x, endingPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentTouch.x, currentTouch.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
touchDraw.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
endingPoint = currentTouch;
touchMoved++;
if (touchMoved == 10) {
touchMoved = 0;
}
}
I don't know that you'll be able to use touch events for this without getting the angles you describe. The resolution of the events just aren't discrete enough.
OpenGL seems a better fit. Check out Apple's GLPaint sample code for an example.
Try using the quadCurve instead of addLineToPoint.. Quad Curve make a line in a two points that don't have an angle and make your line a curve..
CGPoint midPoint(CGPoint p1,CGPoint p2)
{
return CGPointMake ((p1.x + p2.x) * 0.5,(p1.y + p2.y) * 0.5);
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event//upon moving
{
mouseSwiped = YES;
UITouch *touch = [touches anyObject];
previousPoint2 = previousPoint1;
previousPoint1 = currentTouch;
currentTouch = [touch locationInView:self.view];
CGPoint mid1 = midPoint(previousPoint2, previousPoint1);
CGPoint mid2 = midPoint(currentTouch, previousPoint1);
// here's your ticket to the finals..
CGContextMoveToPoint(context, mid1.x, mid1.y);
CGContextAddQuadCurveToPoint(context, previousPoint1.x, previousPoint1.y, mid2.x, mid2.y);
CGContextStrokePath(context)
}
I have a UIImageView that is an arrow image. I added this view to a parent view with a frame of 500x500 dimensions. I want to rotate the UIImageView so that the arrow is always pointing to the center of its parent when the user touches and moves it around.
I was looking into CGAffineTransform and trigonometry rotations, but I'm having trouble getting started. Can anyone provide some insight?
Thanks!
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self];
pointerView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"pointer.png"]];
pointerView.layer.anchorPoint = CGPointMake(0, 0.5);
pointerView.center = point;
[self setPointerRotation];
[self addSubview:pointerView];
[pointerView release];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:self];
pointerView.center = point;
[self setPointerRotation];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[pointerView removeFromSuperview];
pointerView = nil;
}
- (void)setPointerRotation {
CGAffineTransform transform = // calculate rotation so that pointerView points to the center of the superview
pointerView.transform = transform;
}
I was wondering how to draw a CGRect onto an UIImageView. Here is the code I've got but it doesn't seem to be working. Any suggestions? touch1 and touch2 are both CGPoints and point is a CGRect.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
touch1 = [touch locationInView:self];
touch2 = [touch locationInView:self];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
touch2 = [touch locationInView:self];
point = CGRectMake(touch2.x, touch2.y, 50, 50);
[self setNeedsDisplay];
}
- (void) drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2.0);
CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);
CGContextSetFillColorWithColor(context, pointColor.CGColor);
CGContextAddEllipseInRect(context, point);
CGContextDrawPath(context, kCGPathFillStroke);
}
What do you see actually happening?
A few notes:
You shouldn't be doing this with a UIImageView-- those are specifically intended to be containers for image files. You should just use a subclass of a regular UIView for this.
In your touchesBegan, you know that touch1 and touch2 will always be set to the same thing, right? You don't seem to ever be using touch1.
point is a misleading variable name for something that is a rect.
Your drawRect is not unreasonable. What is pointColor? If you're drawing black-on-black that might be part of the problem.
Listing 3-1 Code that creates an ellipse by applying a transform to a circle
CGContextScaleCTM(context, 1,2);
CGContextBeginPath(context);
CGContextAddArc(context, 0, 0, 25, 0, 2*M_PI, false);
CGContextStrokePath(context);
Lots more example code in the Quartz2d Example
I took your code only, its working for me. Just have look at it. And thanks for your code. In this sample i am drawing a rect.
- (void)drawRect:(CGRect)rect
{
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2.0);
CGContextSetStrokeColorWithColor(context, [UIColor blackColor].CGColor);
CGContextSetFillColorWithColor(context, [UIColor redColor].CGColor);
CGContextAddRect(context, rectFrame);
CGContextDrawPath(context, kCGPathFillStroke);
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
startPoint = [touch locationInView:self];
rectFrame.origin.x = startPoint.x;
rectFrame.origin.y = startPoint.y;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
endPoint = [touch locationInView:self];
rectFrame.size.width = endPoint.y - startPoint.x;
rectFrame.size.height = endPoint.y - startPoint.x;
[self setNeedsDisplay];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
endPoint = [touch locationInView:self];
rectFrame.size.width = endPoint.y - startPoint.x;
rectFrame.size.height = endPoint.y - startPoint.x;
[self setNeedsDisplay];
}