I am trying to do some web work and am utilizing leap motion. Does anyone know how to detect when you are touching the edge of the HTML5 canvas you are working in? And if so do you also know how to grab and store that data?
You have to create a mapping between the 3D, real-world coordinate system of the Leap and the 2D, pixel coordinate system of the web page or canvas object. You could, for example, decide that one real-world millimeter equals one pixel and that you are going to ignore the Leap's Z-axis. Then if a finger is 200mm to the right of the origin, then that could mean that the corresponding position on the HTML canvas is 200 pixels to the right of the center of the image.
See https://developer.leapmotion.com/documentation/skeletal/javascript/devguide/Leap_Coordinate_Mapping.html for more information on this topic.
As for getting the 3D finger position in the first place:
* Get a Frame object
* Get a Finger object from the Frame
* Get the tipPosition from the Finger
You will also have to decide when a finger qualifies as touching at all.
Related
The position and rotation of Vuforia's ARcam are determined by their algorithms to give the AR effect. I'd like to know how to do the following:
When some object is clicked the camera goes to some specific position (for that I need to somehow take control of the camera).
Also have to possibility to yield control of the camera back to Vuforia.
You'll want to use a second camera in this instance. Position the second camera at the AR Camera position, then adjust the depths to make the new camera the view that you see. Then you can tween its position to the predefined one you have.
Do the reverse to get control back to the AR Camera.
I am working on a tilemap based game in cocos2d in which the player moves in four directions and I have used four images for the movement of player for example left,right,top and down. My problem is that when my background map change its position or move to other position then my sprite does not change its position. Can anyone tell me how to move a sprite with the movement of background.
Use a CCNode to contain both the background and the sprites for your players. Instead of moving the background, move that node.
There are a couple of ways to handle tilemap based games, and neither of them are very convenient. One way is to leave your character in the center of the screen at all times and move the background underneath it. If your character moves 'right', you simply slide the background to the left, and vice versa. This will give the illusion that the character moves around the map, when in reality it remains centered. Under this paradigm you must remember to convert all detection / collisions into the world's space, and not just the screen space. If you don't convert everything, then your 'range' of collision / detection is limited to the size of the screen.
The second method is to pan the camera over the world. You still keep the character in the middle of the screen, but it actually moves around in the world, and the camera follows. This makes the most intuitive sense to me because it allows you to view the game world as you see the real world. It is also much easier to deal with collisions because the position of the character and the world 'just work' and don't have to be converted. The downside here is that Cocos2D doesn't make it easy to use CCCamera, and the documentation is a little thin in that respect.
In your particular case, it sounds like you have a CCLayer problem. If your character is inside the layer you are moving, it will indeed remain in the same place relative to the map (as you are describing). Instead, float the character in a different layer on top of the map.
You could use a scrolling Parallex and then add the sprite onto the same layer as the background. They will move together.
How should I go about adding camera collision to a terrain in three.js.
The terrain is from 'mrdoob's three.js' examples and is randomly generated and I am currently converting it to height map.
I am thinking of implementing the collision as follows:
Create a 'box' object around the camera
If the box object is not touching the terrain, move the camera down.
If the box object IS touching the terrain, keep the Y axis of the camera.
How should I go about doing this?
The theory is that you send a ray from the location you are (camera position) straight down. You find the intersection point and based on the distance you decide what to do. Implementation wise I cannot help you but THREE.Ray should help you.
I am trying to develop an iOS app to make any given image (UIImage) warp on selected locations.
So for this task to be accomplished what should be the rightmost way going forward, for now i'm doing some research on doing this on OpenGL (frankly any heads up on the framework would be nice too).
So finally the requirement is to get the UIImage warp on some given locations. (If x, y coordinates are there)
If you're sufficiently familiar with (or willing to learn) OpenGL, then you could do this:
Create a flat, rectangular grid of points to be a mesh that will be displayed with OpenGL.
Apply the image to the mesh as a texture.
When distorting the image at a particular location, you can just decide which points on the mesh will be affected by the distortion, and move them.
You can push points out from the center, or in toward a center, or shift them all in the same direction. If the distortion affects a large area, then you change a lot of points (possibly changing those in the center by more than those near the edges of the affected area).
Not sure what you mean by 'warp'. Do you mean skew it in 3 dimensions? If so you can adjust the CGAffineTransform for the UIImageView you are displaying it in to get that effect.
If you mean some kind of image processing warp, and you are using iOS 5, you can use Core Image for that.
I do not really understand the way I'm suppose to render a side-scroller? How do I know what to render when my character move? What kind of positionning should I use for the characters?
I hope my question is clear
The easiest way i've found to do it is have a characterX and characterY variable [integer or float, whatever you want] Then have a cameraX and cameraY variable. Every object in the scene is drawn at theObjectX-cameraX, theObjectY-cameraY...
CameraX/CameraY are tweened by a similar-to-midpoint formula so eventually they'll reach playerx/playery[Cx = (Cx*99+Px)/100] ... yeah
By doing this, every object moves in the stage's space, and is transformed only on render [saving you from headaches]
Use a matrix to define a camera reference frame.
Use space partitioning to split up your level into screens/windows.
Think of your player sprite as any other entity, like enemies and interactive objects.
Now what you want is the abstraction of a camera. You can define a camera as a 3x3 matrix with this layout:
[rotX_X, rotY_X, 0]
[rotX_Y, rotY_Y, 0]
[transX, transY, 1]
The 2x2 sub-matrix in the top-left corner is a rotation matrix. transX and transY defines the translation part, i.e the origin. You also get scaling for free. Just simply scale the rotation part with a scalar, and you have yourself a zoom.
For this to work properly with rotation, your sprites need to be polygons/primitives, say like triangles or quads; you can't just apply the matrix to the positions of the sprites when drawing. If you don't need rotation, just transforming the center point will work fine.
If you want the camera to follow the player, use the player's position as the camera origin. That is the translation vector [transX, transY]
So how do you apply the matrix to entity positions and model vertices? You do a vector-matrix multiplication.
v' = vM^-1, where v' is the new vector, v is the old vector, and M^-1 is the matrix inverse. A camera needs to be an inverse transform because it defines a local coordinate system. An analogy could be: If you are in front of me and I turn left from my reference frame, I am turning your right. This applies to all affine and linear transformations, like scaling, rotation and translation.
Split up your level into sub-parts so you can cull objects and scenery which does not need to be rendered. Your viewport is of a certain size/resolution. Only render scenery and entities which intersect with your viewport. Instead of checking each and every entity against the viewport bounds, assign each entity to a certain sub-screen and test the bounds of the sub-screen against the viewport and camera bounds. If your divide your levels into parts which are the same size as your viewport, then the maximum number of screens visible
at any particular time is:
2 if your camera only scrolls left and right.
4 if your camera scrolls left, right, up and down.
4 if your camera scrolls in any direction, and additionally can be rotated.
A screen-change is an event you can use to activate entities belonging to that screen. That could be enemies, background animations, doors or whatever you like.
If this is your first foray into writing a side-scroller, I'd suggest considering using an already existing game engine (like Construct or Gamemaker or XNA or whatever fits your experience level) so you don't have to worry about what order to render things and how to make it all work. Mess with that a bit--probably exploring a few of them--to get a feel for how they do things then venture out to your own once you've gotten used to it.
Not that there's anything wrong with baptism by fire but it can get pretty overwhelming in my opinion.