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.
Related
Hello everyone There is such a problem - I have a bottle sprite and a sprite showing the water level in this bottle. But, as you understand, if you start rotating the bottle, the level will remain the same. How to make the water rotate realistically? (was always downstairs)
As far as I understand, you probably need a shader, but I'm not strong at all.
I tried to make water in small circles with physics, but it works unstable and the balls periodically slip through the wall.
What I need
What I have
So long as you don't care about liquid sloshing and the volume staying consistent you can use a simple sprite mask.
Note that the box collider isn't necessary, it was just added to illustrate the underlying sprite size.
I'm trying to make a car (or any object) in rotate when sitting on a plane surface or inside a tube shape. Currently the car acts like it has 0 grip on those surfaces (even tough the car moves without any problems when accelerating, but the objects don't move the car)
What I've tried so far:
putting a Physics Material on the tube & plane but has no effect
tuning the parameters of the Physics Material, no effect
marking the animation's Update Mode of the tube and plane as "Animate Physics", no effect
increasing the traction of the car (uses RCC), no effect
increasing the mass of the car..nothing
increasing mass of wheels, nothing
tried googling the problem, either didn't write the right terms or just couldn't find anything
Any help would be appreciated.
Thanks!
You need to rotate the plane and the tube using their Rigidbody with the AddTorque method or similar. If you just rotate them via their transform it has no effect on the physics system.
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.
Hello everyone I an very new to cocos2d, so I apologize if this is a simple question. I would like to create to sprites that collide when they hit each other.
For instance, one sprite, spriteA, is in a fixed position on the screen. And another sprite, spriteB, is moving around the screen. SpriteB will collide with spriteA. If that doesn't make sense or you don't understand it, tell me and I will elaborate further. Any help is appreciated. Thank YOU!
Try using Chipmunk or Box2d physics systems. These are included with Cocos2d and work by having a physics simulation that updates with every time the graphics change on screen.
The physics simulation will tell you if two objects are overlapping, and will provide physical attributes like weight, slipperiness (friction), speed and direction, which creates reactions like bouncing, sliding, realistic loss of speed and changes of direction on impact.
If you are new to physics simulation, here's a 30 second run down:
Create "bodies" in the physics simulation that represent each graphical sprite
Bodies are usually defined more simply than their graphical counterparts, like a circle, square or simple polygon shape
In order to update the graphics on the screen accurately, first you establish a pixels to meters ratio. Meters are notional (i.e. made up) measurement that is used in the physics sim
Each time the physics simulation "ticks", you update the graphics on screen accordingly
So if a body in the physics sim moves 1 meter, you might transform the pixel sprite 32 pixels
Here's a good tute on collision detection using Box2d.
http://www.raywenderlich.com/606/how-to-use-box2d-for-just-collision-detection-with-cocos2d-iphone
enjoy
Its actually very simple:
Just schedule a timer: [self schedule:#selector(checkForCollision:)];
Specify the method: - (void)checkForCollision:(ccTime)dt {}
In the curly braces, make CGRects for each sprite using CGRectMake.
Then in the same method, just call: if (CGRectIntersectsRect) {}
That easy!
Well technically speaking when the 2 sprites interact, or share at least one common point, then they are colliding. I'm a little confused by your question. Are you asking for direction on how to make the sprite move on screen, or are you asking how to handle the actual collision(such as calling a method if they collide)?
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