I'm working on making a new app in xcode and have run into two problems that always seem to be a problem when I program large projects.
Basically, I want the user of this app to be able to input specifics like size, position, color, and possibly speed and/or direction.
These inputs will create a square of specific size, position, and color which will move around the screen and interact with other squares the user has created.
Now here are my problems:
First: I have absolutely no idea how to create something in code. I know I almost certainly have to do this in a class, but I've never figured out how to do this in a single programming language.
Second: Interaction between the squares. How do I detect collisions between the possibly dozens or hundreds of squares the user creates.
I'd really like to figure out how to do this, especially because I'm sure it'll be helpful in not only this, but many other future projects.
Thanks
I would recommend using sprite kit for the collision detection and creation of the squares. You'll probably want to subclass SKSpriteNode to define the properties for your squares.
https://developer.apple.com/library/ios/documentation/GraphicsAnimation/Conceptual/SpriteKit_PG/Introduction/Introduction.html
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I just don't get it. For example: I'm making a game with enemies. I made some pics and put it into atlas. I want an enemy to stand still before he will collide with hero and then implement an animation. Should I add first pic from atlas to represent an enemy at first and then somehow add all atlas to that pic to animate it? Also, if I want to make the size of an enemy as twice the hero size: do I need to code it only for the first sprite (if I need to add it first) or for every sprite one after another or even the whole atlas itself? I can't understand how to interact with them!
Also, I'm trying to make game universal, is that correct to name sprites like enemy001#1x.png; enemy001(at)2x.png; enemy001(at)3x.png and put it in one atlas? I'll appreciate any help with this, thanks!
I'm coding it with swift if that matters.
Your question is too confusing in what your are specifically asking.
"I can't understand how to interact with them!"
is not a good question. You need to be more precise and break it down into several questions if need be. However, below are some pointers which might clarify some issues for you.
You typically preload a texture atlas to avoid delays during your game play.
When you init a SKSpriteNode you can either use a texture (preferred when using an atlas) or an image.
To animate a sprite you run a sequence of images. There are several ways of accomplishing that. For example: -(SKAction *)animateWithTextures:(NSArray *)textures timePerFrame:(NSTimeInterval)sec would run an animation sequence of images placed into the NSArray.
Sizing for different screen sizes has been asked numerous times on StackOverflow. Do a search and see what comes up.
New user to the site, but I have used it in the past so I felt it best to ask my question here, for the best chance of getting a response.
What I'm dealing with is one object, this being the sprite for my latest app, which I need to check for when it comes in to contact with another object, in this case, a tunnel which will curve.
Now, I'm aware of CGRectIntersectsRect, however I can't see that being helpful, as if I've got 2 UIImages, that being the top and bottom of a "mountain", and said pieces curving, there's no doubt that the sprite would touch the "rectangle".
What I need is something to trigger when the sprite hits the actual wall, however my limited knowledge of Objective-C isn't helping my case.
I imagine someone out there will know what I can do to resolve this, as for all I know it could be a simple solution.
Thank you in advance everyone!
First, I'd probably not build these basic pieces yourself. For iOS 7, you can use SpriteKit, which is built-in. If you want to support older versions of iOS, look at cocos2d (it's good for iOS 7, too).
But to the question, one approach for detecting arbitrary overlaps is to draw both objects into a buffer and check if there are any overlapping pixels (for instance, by drawing one in in pure red, and another in pure green, and then looking for pixels that have both). For a discussion of how to do this kind of thing in Core Graphics, see Clipping a CGRect to a CGPath, which provides sample code for the simplest version (checking for the intersection of a rectangle and curve), but the same approach can be used more generally. Note that this drawing can get expensive if you're doing it constantly, so usually you first check whether the bounding rectangles overlap. That tells you whether it's even worth the trouble to look closer.
But first I'd look at SpriteKit.
let's say I want to display a customizable (2D, cartoon-like) character, where some properties e.g. eye color, hair style, clothing etc can be chosen from a predefined set of options. Now I want to animate the character. What's the best way to deal with the customization?
1) For example, I could make a sprite sheet for each combination of properties. That's not very memory efficient and not very flexible, but probably gives the best performance.
2) I could compose the character from various layers, where each property only affects one layer. Thus, I could make a sprite-sheet for the body, a collection of sprite-sheets for the eyes (one for each eye color) etc.
2a) In that case, I could merge the selected sprite-sheets in order to generate a single sprite-sheet containing the animation of the customized character.
2b) Alternatively, I could keep the sprite-sheets separate and try to animate them simultaneously as layers. I fear, that this might become a problem performance-wise.
3) I could try to modify the layers programmatically, e.g. use a sprite-sheet for the eyes as a mask and map some texture on it before merging it down to a single sprite-sheet. I would think this is a very flexible approach when it comes to simple properties like eye colors, but might become difficult for things like hair-style. I am aware that this depends much on the character and probably a general answer is difficult.
I assume that my problem is not new, so there is probably a standard approach to it.
Concerning the platform, I'm particularly interested in iOS and try to avoid OpenGL (well, I'm open-minded). Maybe there is a nice framework that can help me here?
Thanks!
Depending on what your working on, you might want to animate part/all of the animations outside in another tool, such as flash. It is much easier to work with a visual environment.
Then there are tools that take swf files, and create sprite sheets that you would then animate in cocos2d.
That is a common game creation workflow.
You problably want to take a look on how to create sprites at cocos2d.
Cocos2d comes with a set of tools that help you to animate single parts and offers abstractions to compose parts (like CCBatchNode or CCNode). Also, it comes with tools that helps you to pack sprites into sprite sheets (e.g Texture Packer) and develop levels (e.g Level Helper).
Cocos2d is an open source framework and it is widely used. You also have cocos3d but I never used it :).
I am making a game where bullets are involved. Its a machine gun, so there will be more than one bullet on the screen at the same time. How to I write the code for the properties and actions of one bullet and apply that to all of them, like multiple instances of the one bullet?
The key point to making a game is the concept of sprite, i.e., a light-weight object that has a graphical representation and that you can move around (managing collisions, etc).
You could try to implement sprites on top of CALayers, using Core Animation, or you might decide to use a game framework like Cocos2D.
For the first approach have a look at this short tutorial. This could also help you if you want to implement your sprites using UIImageViews, although you have to keep in mind that CALayer are light-weight, UIView are not, so if you plan to have many of them that could make a difference.
As to the question of replicating the bullet, basically the key suggestion would be using some form of caching, so that you do not end up replicating the same image in memory multiple times. A very basic caching mechanism is available with the UIImage class if you use the convenience constructor imageNamed.
Again, if you plan to make a full fledged game with a good performance (say 40-60 fps), the best suggestion is using Cocos2D, which will offer you all the power of Open GL graphics wrapped in a simple interface.
Have you tried subclassing UIImageView? That way you can have a function createBullet that creates a subclassed UIImageView and adds it to the screen, and in the subclass it can contain functions and properties for animating etc...
Right now I have coded about 80% of my game and the remaining 20% is the actual game part of it. I need to know how I should go upon actually making the game part.
Pretty much it will be somewhat similar to Doodle Jump. There will be gravity, the accelerometer, and a spawn system for platforms. I need to know if I should use UIKit or Cocos2D for this.
I know I can do gravity and use the accelerometer easily using UIKit but I am worried about the platform part. My 'Doodle Jump character' is not a regular square or rectangle so should I just crop it as best I can? The reason I am worried is because say the character falls on a platform, so his body could be a little off since CGRectIntersectsRect does not have pixel collision detection, so do you think it is fine the way it is?
If you need more info or aren't sure what I am trying to do, just let me know. In the end I just need to know if I should use Cocos2D or UIKit.
Please let me know your thoughts.
Thanks!
My answer would be that, while you may be able to develop the game in UIKit, my suspiction is that it will be better in the long run to do it in Cocos2D. Not only will you have tools which are better for doing stuff like collision detection, you can also use a Physics Engine to handle the gravity and things like that. Basically, Cocos2d was made to do exactly the kinds of things you want to do, and UIKit wasn't...it was made for user interfaces.
Still, the collision detection you do will, mostly likely, not need to be down the level of individual pixels. One rectangle might be enough, or perhaps you can use several to get more accuracy. So can you pull it off in UIKit...maybe, but I bet your game will turnout better overall if you use Cocos2d.