I'm developing a game with large obstacle and sprites(in cocos2d+box2d for iPhone), then after zooming out my sprites and layer (by increasing cameraZ), I make my game to play by user, which causes some problem in touch detection of dynamic objects.
Can it be said a good approach to work with? If No then what will be the solution to work properly(consider that I have traveled so far with this approach)?
NOTE:[self.camera setEyeX:0 eyeY:0 eyeZ:180]; (i'm using this line for zooming out, putting camera far from my sprites by increasing z)
If you use a camera for zooming then cocos2d will no longer correctly convert your touch locations to opengl coordinates, since it doesn't invert the camera transform. I would recommend using scale on the layer that your objects reside on to implement zooming. This gives you precise control over the zoom factor and touches will be correctly transformed when you use methods to convert touches from screen space to node space.
Related
I am trying to wrap my head around Vuforia's capabilities. I want to make an app which lets me place a 3D object into a camera view and have that 3D object stick to the world. I've been learning how to use Vuforia in Unity3D, and Vuforia seems to be slightly capable of this, but is severely limited by its craving for "Targets". It doesn't seem to be able to do much if I don't give it some sort of target.
One workaround I've found is to set the ARCamera's World Center Mode to DEVICE_TRACKING. This seems to let me place a 3D object into the world (in Unity) and have this object overlay into the camera feed, almost making it seem like it's anhcored to the real world. This doesn't work perfectly though: it tracks properly when I angle the device up/down/left/right (rotation), but it does not seem to track the device's translational motion; that is, when I move the device forward/back/left/right, the overlaid object doesn't get closer/farther nor does it rotate as I move around it.
Is it possible to get this sort of tracking out of Vuforia, or am I better off switching to something like Google Tango?
The difficulty with setting World Center Mode to CAMERA in Vuforia is that apparently 3D objects rotate around the camera based on its accelerometer/gyroscope changes. This doesn't allow for objects to be anchored to the environment. Instead they follow with the camera.
Kudan is a good markerless tracking option.
What's the best method for pulling back to show more of a view in a 2D OpenGL iPhone game? For instance, in Tiny Wings, when the bird flies toward the top of the screen the bird and the scenery pull back to simulate the bird going higher in the sky. Would this effect be better achieved by scaling all the sprites proportionally, or by using glOrthof? In any case, I'm assuming that the zoom-out factor is inversely proportional to the player's y position.
You almost certainly want to use glOrthof so all you're changing is how the camera sees the scene. This avoids recomputing all the normals and such in the scene, saving quite a bit of work. It's also easier for you to implement.
We are trying to achieve the following in an iphone game:
Using 2d png files, set-up a scene that seems 3d. As the user moves the device, the individual png files would warp/distort accordingly to give the effect of depth.
example of a scene: an empty room, 5 walls and a chair in the middle. = 6 png files layered.
We have successfully accomplished this using native functions like skew and scale. By applying transformations to the various walls and the chair, as the device is tilted moved, the walls would skew/scale/translate . However, the problem is since we are using 6 png files, the edges dont meet as we move the device. We need a new solution using a real engine.
Question:
we are thinking of instead of applying skew/scale transformations, that if given the freedom to move the vertices of the rectangular images, we could precisly distort images and keep all the edges 100% aligned.
What is the best framework to do this in the LEAST amount of time? Are we going about this the correct way?
You should be able to achieve this effect (at least in regards to the perspective being applied to the walls) using Core Animation layers and appropriate 3-D transforms.
A good example of constructing a scene like this can be found in the example John Blackburn provides here. He shows how to set up layers to represent the walls in a maze by applying the appropriate rotation and translation to them, then gives the scene perspective by using the trick of altering the m34 component of the CATransform3D for the scene.
I'm not sure how well your flat chair would look using something like this, but certainly you can get your walls to have a nice perspective to them. Using layers and Core Animation would let you pull off what you want using far less code than implementing this using OpenGL ES.
Altering the camera angle is as simple as rotating the scene in response to shifts in the orientation of the device.
If you're going to the effort of warping textures as they would be warped in a 3D scene, then why not let the graphics hardware do the hard work for you by mapping the textures to 3D polygons, then changing your projection or moving polygons around?
I doubt you could do it faster by restricting yourself to 2D transformations --- the hardware is geared up to do 3x3 (well, 4x4 homogenous) matrix multiplication.
I'm making an iPhone game in cocos2d.
I was wondering how I would make the camera / the view follow a specific sprite?
would I use the CCCamera class?
Yes, CCCamera would work. However, it has some drawbacks that make it undesirable for some uses. Moving the layers respectively all other objects relative to that sprite may be a better solution. It depends on the game.
First, read up what the different approaches and their drawbacks are, you can get a lot out of this cocos2d forum thread:
http://www.cocos2d-iphone.org/forum/topic/5363
It would be helpful if you could describe what your game is about and why you need the camera attached to that sprite.
For example, if you're thinking of a running game like Canabalt, i would not use the camera to scroll over the world, but instead scroll everything relative to the player (towards him) with the player sticking at about the same x coordinate while running. Perfect examples of games where you would not move the camera at all are the iCopter games, they are basically simplified versions of Canabalt. Notice that the player sprite always stays at the exact same x coordinate, and the game world just scrolls
Scrolling the camera itself in my opinion makes the most sense if you have a large game world that the player can traverse in all directions, and the number of objects are simply too numerous and also moving about in various directions, so updating their positions individually each frame would be both overkill and prone to errors. And since the game world is so huge, you would want to use the camera's position to limit what is drawn on screen.
use CCFollow actions
Like these :-
[self runAction:[CCFollow actionWithTarget:(u r hero) worldBoundary:CGRectMake(0,0,1050,350)]];
it will helps
im developing a 2d game on iphone in which i want to maginify the views on the screen to give the effect that the user is looking through the sniper whenever the user taps the screen..
i am required to show that the objects which the player wants to shoot should be moving...so im incremeting their position as well as increasing their size...
so i want this magnified image to show the updated positions of the moved objects at runtime to give the effect that the user is looking through the snpier...
scaling the images didnt help me cause it slowed my application a llot as the objects position is updated every 0.01 sec...
please help
Is it a 2d game, or are you using OpenGL ES? If the latter, you can always render your scene to a texture and use the hardware to scale that for you. That shouldn't slow down the game too much...
If 2d, it's always faster to scale one single image than a lot of individual objects, so here it also may be beneficial to render to an image first, and later scale and draw it on the screen.