I have an app with some annotations on it, and up until now they are just symbols that look good with the default behavior (e.g. like numbers and letters). Their directions are fixed in orientation with the device which is appropriate.
Now however I need some annotations that need to be fixed in orientation to the actual map, so if the map rotates, then the annotation symbols need to rotate with it (like an arrow indicating the flow of a river for example).
I don't want them to scale with the map like an overlay but I do want them to rotate with the map.
I need a solution that primarily works when the user manually rotates the map with their fingers, and also when it rotates due to be in tracking with heading mode.
On Google Maps (at least on android) this is very easy with a simple MarkerOptions.flat(true)
I am sure it won't be too much more difficult on ios, I hope.
Thanks in advance!
Here's what I used for something similar.
- (void)rotateAnnotationView:(MKAnnotationView *)annotationView toHeading:(double)heading
{
// Convert mapHeading to 360 degree scale.
CGFloat mapHeading = self.mapView.camera.heading;
if (mapHeading < 0) {
mapHeading = fabs(mapHeading);
} else if (mapHeading > 0) {
mapHeading = 360 - mapHeading;
}
CGFloat offsetHeading = (heading + mapHeading);
while (offsetHeading > 360.0) {
offsetHeading -= 360.0;
}
CGFloat headingInRadians = offsetHeading * M_PI / 180;
annotationView.layer.affineTransform = CGAffineTransformMakeRotation(headingInRadians);
}
And then, this is called in regionDidChange etc.
Unfortunately, this solution doesn't rotate while the user is rotating the map, but it corrects itself afterwards to make sure it has the proper heading. I wrap some of the affineTransform into an animation block to make it look nice.
Hopefully this can help, or maybe help get you pointed in the right direction.
Related
I am working on an iOS application that works like Uber. When the device moves I am moving the car marker as well. But am not able to turn it as per turns on road like Uber does. How can I make it possible?
Also how can I keep this car marker only on road?
You can calculate bearing then rotate marker based on the calculated bearing.
Use this function to calculate bearing:
+(float)getBearing:(CLLocationCoordinate2D)locations1 andSecond:(CLLocationCoordinate2D)locattion2
{
float fLat = degreesToRadians(locations1.latitude);
float fLng = degreesToRadians(locations1.longitude);
float tLat = degreesToRadians(locattion2.latitude);
float tLng = degreesToRadians(locattion2.longitude);
float degree = radiansToDegrees(atan2(sin(tLng-fLng)*cos(tLat), cos(fLat)*sin(tLat)-sin(fLat)*cos(tLat)*cos(tLng-fLng)));
if (degree >= 0) {
return degree;
} else {
return 360+degree;
}
}
Then rotate the marker itself using rotation property
marker.rotation = CALCULATED_BEARING - 180;
Take a look at rotating the marker alongside the update or the moving of locations with regards to the bearing. Not really sure how you can achieve with keeping the marker on the road since you are relying on the gps to provide exact location where you will place your marker.
Take a look at this SO as a sample.
I'm trying to make a game where the sprite will always move to the right when hit by an object. However since the Sprite rotates constantly and the zero radians rotates with the Sprite causes my calculated magnitude to go the opposite direction if the sprite is facing left and hits the object. Is there a way to keep the direction of the magnitude always pointing to the right even if the zero is facing left?
// referencePoint = upper right corner of the frame
let rightTriangleFinalPoint:CGPoint = CGPoint(x: referencePoint.x, y: theSprite.position.y)
let theSpriteToReferenceDistance = distanceBetweenCGPoints(theSprite.position, b: referencePoint)
let theSpriteToFinalPointDistance = distanceBetweenCGPoints(theSprite.position, b: rightTriangleFinalPoint)
let arcCosineValue = theSpriteToFinalPointDistance / theSpriteToReferenceDistance
let angle = Double(acos(arcCosineValue))
let xMagnitude = magnitude * cos(angle)
let yMagnitude = (magnitude * sin(angle)) / 1.5
Not sure if this works for you:
I would use an orientation constraint to rotate the sprite. The movement can be done independent from the orientation in that case.
I made an tutorial some time ago: http://stefansdevplayground.blogspot.de/2014/09/howto-implement-targeting-or-follow.html
So I figured out what was going on.
It seems like the angle doesn't rotate with the Sprite like I originally thought and the vector that I am making is working with the code above. THE problem that I had was that I also set the collision bit for the objects which is wrong. If I only set the contact bit for the objects against the sprite the my desired outcome comes true.
I have a BIG problem!! I want to make something like old space shooter games like “Asteroids”, where the ship, when going out of the screen, is reappearing at the other side. For example, when the ship go out at the top of the screen, it come back at the bottom. But in my game, there’s a camera following the player, showing only a quarter of the world, and I want to simulate an infinite world this way! Here’s a picture showing what I mean :
What I thought doing was simulate the scroll by only moving game objects, stored in an array, but not the player, and calculating at every frame if the objects are out of the world boundary and re-adding them at the other end of the world (i.e going out at the left would add it back at the right).
But I don’t really like that way of doing… I’d like something more… intuitive..?
Do you guys have any idea of how doing it? Like, any tutorial on the web or just the right words to explain what I mean so I could do a bright research on google (I’m french, so I had a really hard time writing that question)!
Thank you in advance!
Knowing the players position, x,y check to see if the player is within the bounds of the area. If the player has left those bounds, set the player's position to the opposite bounds, possibly adding width/height. I'll do it here for the Y coordinate only:
const float minWarpAreaY( 0 );
const float maxWarpAreaY( 400 );
//if (player.y < minWarpAreaY) { player.y = maxWarpAreaY - player.height; }
//if (player.y > maxWarpAreaY) { player.y = minWarpAreaY + player.height; }
if (player.y < minWarpAreaY) { WarpPlayer(0.0f, (maxWarpAreaY - minWarpAreaY)); }
if (player.y > maxWarpAreaY) { WarpPlayer(0.0f, -(maxWarpAreaY - minWarpAreaY)); }
void WarpPlayer(float amountX, float amountY)
{
player.x += amountX;
player.y += amountY;
for (eachObject in World)
{
eachObject.x += amountX;
eachObject.y += amountY;
}
}
Something along those lines should help.
I am working with quaternions and the XNA skinned model example(for weeks now......). I am received two sets of quaternions from some open source sensor boards that you can buy these days on the net. I was able to write some code so that I receive these quaternions and I am able to rotate limbs with them. Now my problem is the following. I am using the upper right arm and lower right arm in my example and I am able to rotate them separately. My initial position is the one depicted below, which perfect.
http://i.imgur.com/c7qei.png "initial position"
Now when I want to rotate my right arm forward I should have my final position as shown below on the right in this figure. But somehow the result is the one position of the left but my real "physical" arm is pointing forward.
http://i.imgur.com/tXCp6.png "ideal final position(right), real wrong position(left)"
Some how the lower arm does not compensate for the rotation of the upperarm. I am sure I am missing one small step. Here below I have put the crucial part of the code I am using
protected override void Update(GameTime gameTime)
{
HandleInput();
UpdateCamera(gameTime);
// Read gamepad inputs.
float initposition = currentGamePadState.ThumbSticks.Right.X;
float armRotation = Math.Max(currentGamePadState.ThumbSticks.Right.Y, 0);
// these quaternions are received from bluetooth
Upper.Z = Fq1;
Upper.Y = -Fq2;
Upper.X = -Fq3; // set 1 quaternions
Upper.W = Fq4;
//***************************
forearm.Z = Uq1;
forearm.Y = -Uq2;
forearm.X = -Uq3;
forearm.W = Uq4; // set 2 quaternions
// set initial position
if (initialpos == true)
{
initposition = 0.9f;
R_forTransform = Matrix.CreateRotationY(initposition);
R_forarminderinit = skinningData.BoneIndices["R_UpperArm"];
L_forTransform = Matrix.CreateRotationY(-initposition);
L_forTransform = Matrix.CreateRotationX(-initposition);
L_forTransform = Matrix.CreateRotationZ(-initposition);
L_forarminderinit = skinningData.BoneIndices["L_UpperArm"];
}
// Create rotation matrices for the upper and lower arm bones.
Matrix upperarmTransform = Matrix.CreateFromQuaternion(Upper);
Matrix forearmTransform = Matrix.CreateFromQuaternion(forearm);
animationPlayer.GetBoneTransforms().CopyTo(boneTransforms, 0);
if (initialpos == true)
{
boneTransforms[R_forarminderinit] = R_forTransform * boneTransforms[R_forarminderinit];
boneTransforms[L_forarminderinit] = L_forTransform * boneTransforms[L_forarminderinit];
}
int forearmindex = skinningData.BoneIndices["R_Forearm"];
int upperarmindex = skinningData.BoneIndices["R_UpperArm"];
boneTransforms[upperarmindex] = upperarmTransform * boneTransforms[upperarmindex];
boneTransforms[forearmindex] = (forearmTransform) * boneTransforms[forearmindex];
animationPlayer.UpdateWorldTransforms(Matrix.Identity, boneTransforms);
animationPlayer.UpdateSkinTransforms();
UpdateBoundingSpheres();
base.Update(gameTime);
}
I would like to ask you if you could help me solve this mystery. I hope I have been as clear as possible in describing my problem. Furthermore I would like to thank you in advance for you effort.
Yours
Dave
It looks to me like you have some mixed-up reference frames. Here's what I think I'm seeing:
Your external sensors report their orientation relative to the world. Your rendering code, on the other hand, deals with the lower arm in the upper arm's reference frame.
If we assume that the initial orientations are q_u = [0,0,0,1] and q_l=[0,0,0,1], when you rotate your arm to point forward, the new orientations are both [0,.707,0,.707], or something like that because both arm segments have experienced a rotation of π/2 relative to the world.
When you render the arm, you rotate the entire arm (not just the upper arm) by q_u. This makes sense, since you want to make sure that the elbow stays connected. But then you rotate the lower arm by q_l and it has rotated twice as far as it should because it holds the shoulder's rotation. If you were to hold your arm straight, but turn your body around, you would see the same thing happen: the upper-arm would rotate by the amount of body rotation and the lower-arm would rotate by that much again.
Perhaps the easiest way to deal with this is to remove q_u from q_l. If q_k is the rotation of the lower arm relative to the upper arm, then q_k = q_u' * q_l where q_u' is the inverse quaternion (just negate the w component).
I'm currently trying to make a basic platformer with XNA and I'm wondering how to create a "jumping effect." I currently have basic keyboard input which allows for sideways movement, but I would like my sprite to slowly progress into a jump rather than instantly teleporting there (right now I have something like Rectangle.Y += 40 every time I jump, making the sprite instantly appear there). Does anyone have any insight?
I'm not totally across how to implement this in XNA/C#, but in Flash games I've made I just added a vertical velocity property. I'll try write everything as C# as I can..
Example; create the velocity property:
float verticalVelocity = 0;
Vertical velocity should be constantly reduced (by gravity). Set up a gravity property somewhere accessible from your player:
float Gravity = 2.5;
And in your update() method for the player, increment the verticalVelocity by Gravity. Also increment the Y position of your player by the verticalVelocity. This will simulate falling:
verticalVelocity += Gravity;
Position.Y += verticalVelocity; // this may be -= in XNA, not sure where the y axis beings
When you hit a surface, the velocity should be reset to 0.
And finally, to jump, simply subtract a given value from verticalVelocity:
public void Jump(float height)
{
// Only jump if standing on a surface.
if(verticalVelocity == 0)
verticalVelocity -= height;
}
You'll eventually want to add gravity and possibly other forces to your game, so I highly recommend you save yourself a lot of pain and implement some kind of basic force system. This can be done using Vector2s, as you can just add them to the speed of your character. Then just apply an instantaneous force to your character to push it up.
If you really don't want to use a physics engine, you can make a Vector2 with the high point of the jump for the Y and the characters X, and then use the Vector2.Lerp method to interpolate between the characters position and the end point of the jump.
This is generally a very bad system to use, and I highly recommend you either use an existing physics engine, or make your own simple one.
use a sinusoidcode should look something like this:
float ground = 0.0f;
float angle = 330.0f;
jump(){
if(ground == 0.0f)ground = Rectangle.Y;
if(Rectangle.Y <= ground)
{
Rectangle.Y+=Math.Sin(angle/(Math.Pi*180));
angle++;
}
}
You can accurately create a gravity effect if you modify the ySpeed dynamically, as opposed to just adding 40.
You want to declare a ySpeed
ySpeed = 0;
Then you want to use an acceleration variable
acceleration = 0.25;
Okay, now that we've done that, let's add gravity, provided that our player isn't touching the floor.
if(playerLocationY + playerHeight > floorLocationY)
{
gravity = false;
}
else
{
gravity = true;
}
if(gravity)
{
ySpeed += acceleration;
}
Now that we've got that down, we want to include something that allows us to jump.
if(KeyPressed == UP)
{
ySpeed -= acceleration;
}
This will move our player in the upward direction
We now want to make sure we actually move, so let's add one last line and we're done.
playerLocationY += ySpeed;
Congratulations, you made it.