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.
Related
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.
So, how can I do this?
For example, my person goes right and camera starting to move to persons coordinates with acceleration, when he stoppes - camera moves to persons coordinates with deceleration. Of cource, I can make it by myself, but is there any library that can help me with it?
I'd suggest using Universal Tween Engine. You could add a short deleay and proper math equations to smooth out the camera transitions.
http://www.aurelienribon.com/blog/projects/universal-tween-engine/
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.
I have a sprite and if it is touched the touch should be recognized. I used the coordinates to do so. I took the coordinates (min x, min y, max x , max y)of the sprite image. But The sprite image is not a rectangular shape. So, even if I touch the coordinates outside the sprite and inside the rectangular bounds the sprite is recognized.
But for my application I need only the sprite to be recognized. So, I have to take only the coordinates of the sprite, but it is not regular shape. I am using CCSprite in my program.
So, what can I do to for only the sprite to be selected ? Which classes should use for this?
Thank You.
You could try one of the following...
Create a bounding box smaller than the absolute extents of the sprite image. Yes it will be smaller than the sprite. This will eliminate the dead space click detection of the sprite the trade off being parts of your sprite which look selectable won't be
Use a circular bounding area to detect if the user has clicked on your sprite. Again you will have the dead space problem in my first suggestion but the sphere may give you some better coverage area over the sprite giving you better results on touch detection
This is a standard problem in physics collision detection systems which often end up using circles or rectangles as their collision bodies. I would go with the either a circle or rectangle smaller than the size of your sprite as your bounding area. Going finer detail than that you could generate bounding area polygons. This would however introduce a whole bunch of new issues and concerns.
I am building a Cocos2D game right now and what I am doing is first I step through my sprites and see which sprites the touch hit (they overlap in my app)
Then, for each sprite hit I use [sprite convertTouchToNodeSpace] to get an X,Y co-ordinate inside the sprite, which I can use (although the Y axis is flipped) to reference the CGImage I created the sprite with.
If the pixel at the touch point is 'clear' ie alpha 0, then the sprite was not really touched, and I check the next sprite in the z-order to see if it has color where it was touched.
Sometimes I think I should be using a two color mask image to go along with each sprite, not the sprite image. But, I am mr. make it work, then make it fast.
I realise this is not super efficient, but I do not have very many sprites and I do this only for touches.