How to clip part of a sprite based on its position? - objective-c

I'm designing a game in Cocos2d, and at one point I have coins shooting out on a platform from a zelda-ish perspective. I'd like to display the coin's shadow sprite (a different sprite from the coin) on the platform, but mask or clip the shadow sprite on the edge of the platform. The coin can continue off the edge of the platform, but the shadow should stop at the edge. The platform also moves, so I need the shadow sprite to track with the platform's movement.
I thought it could work to use a CCClippingNode for this, but I can't add it as a child of anything in a spriteBatchNode which is how I'm making my platform. Without having the shadow as a child of the platform, I'll mess up z-order and the shadow movement won't track correctly. I also checked out Ray Wenderlich's tutorial on masking a sprite but I don't think that'll work since it looks like it masks an individual sprite texture and not an area of the view where the sprite shouldn't be displayed. Any ideas on how to solve this?

Related

Create scene in blender

How can one create a scene/terrain like clash royal's game scene in blender? The game scene seems like top view but is not exactly top view. At what angle should the camera be placed to get that effect?
You would be looking for isometric projection or maybe 2.5D, also called 3/4 perspective. You can find several isometric tutorials on youtube.
While I'm not sure if there are any strict rules to follow unless you are making graphics that must fit in an existing game, it is common to use an orthographic camera at about a 45 degree angle.
Clash Royale looks like it could be close to a 45 degree orthographic camera angle.

Solution for relative position of nodes in Sprite kit scene editor?

I am just a beginner in game developing. Right now I am developing a game using Apple's Sprite kit and found out that the best way to position nodes on the scene is to provide percentages of width and height of the window boundaries as it makes sure all the nodes maintain their positions almost regardless of change in device display size. Using pixels to position nodes is not a peculiar idea as with the change in device display size of iPhone, nodes are either cut off or the scene squeezes leaving empty space around the scene boundary. I have watched how Apple recommend using scene editor but my issue is, using scene editor it allows you to position nodes by choosing pixels and not relative to to scene width or height. Am I making a mistake in understanding the scene editor capability. If I position all my nodes using scene editor as its saves a lot of time, how can I avoid problem with different iPhone sizes. I appreciate your help.
This is an age old problem, from all media formats.
You must decide, personally, what your favourite and most desirable target device is, and then make choices best for both it, and your creative process.
After making that decision you'll have to make your own decisions on how compromised you become on other devices, or how much you compromise your creative and production processes to benefit other device sizes and aspect ratios.
It's a balancing act.
And I strongly suggest favouring your favourite device and putting off all consideration of adaptation to other devices until after you've made something great.
Others will disagree.

How to move the sprite with the movement of background?

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.

Three.js: Camera Collision on Terrain

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.

How to recognize the touch of a non regular sprite image?

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.