I'm doing a game like tetris. There are objects which are falling from the top to the bottom of the screen. When the pile of object reach the line, the game is over.
I tried to set a boolean to detect when the object pass 2 time in the line the game ends, but it don't work like that so I don't really know how to do this.
Maybe we can detect if the object stands on the line more than 2 seconds ?
Thanks
EDIT:
To simplify the problem I put the line of the top of the screen (self.frame.height), and I spawn the objects under this line, so they never cross the line before the game is over.
The problem now is I have to spawn the objects 40 pixels below the line, or a collision is detected at the spawn point. (It does nothing if I set usesPreciseCollisionDetection = true).
So the 40 pixels collision detection are normal ?
Why would the item pass the line 2 times? Items always move down. So really, once an item is past the line, you know it will never go above (Well, OK, that's not true -- since you can rotate an item, you could get a long one horizontal and then rotate it to vertical ... do Tetris items come out horizontally?).
So really, your test would be more "does it never fully cross the line". E.g. if you know that an item moves at speed X, you could probably just calculate the time it should take to move from top to past the line, then wait that long, then see if it still intersects the top area above the line. If it does, the game is lost.
Alternately, you could set a flag when an item comes to rest on another item. If that flag is set, and the item still intersects the area above the line, the game is lost.
PS - Keep in mind that Tetris is a brand name. Be sure to name your game something else. :-)
Related
i'm new in the development of swift ios game using spirtekit and i need help. I want to develop a vertical 2d endless run, where with a swipe you are able to move the player in direction and if there is an obstacle, it is created in a position calculate with the position of the player. Once create the obstacle i would like to make it falling down but alway with the same relation with the player (this means that it has to move only on y axis).
Can you suggest me some ideas on how to manage this?
This book teaches you exactly how to make what you are looking for:
https://www.amazon.com/Getting-Started-SpriteKit-Jorge-Jordan-ebook/dp/B01891X7TM
This is the end product:
https://itunes.apple.com/lr/app/inside-the-hat/id1076967804?mt=8
You can get it for free here (with trial):
https://www.packtpub.com/application-development/getting-started-spritekit
The source code for this is around somewhere on the web, but I forgot where :( I bought the book a year ago and can't find it now.
Basically, you have a long background that is .moveTo .. in .update you check the position of the background, then reset it based on its XY position (it basically just goes all the way down, warps to the top position, then falls)
Also in .update you check for score, or a timer, or just a random check, then spawn an enemy, obstacle, etc. You give the enemy / obstacle SKActions to move towards the player, and let .didBegin(contact:) handle scoring, sound effects, death, etc.
I'm making a platformer using Actionscript 2. I got the jumping and gravity and everything going, but I'm limited to one "ground". As one might imagine, platformers require multiple "grounds" for jumping onto and falling off of. I tried editing the "ground" movie clip so that it was several blocks with nothing between them, but when I try this, my character will jump, land at the peak of its jump, and repeat the process until it lands on the top of the ground movie clip, then behave regularly, jumping and landing on top of the ground movieclip, even if there's no part of the ground movieclip to land on.
Here's my ground-gravity code.
if(this.hitTest(_root.ground))
{
this._y -= gravity;
gravity = 0;
jumping = false;
}
When you use hitTest between two MovieClips, it doesn't matter if there's nothing inside the movieclip, as long as the hittesting movieclip is INSIDE the bounding box (the blue outer rectangle of a movieclip when you select it) of the other movieclip.
To solve your problem, but still have many grounds in the same MovieClip, you have to use the second usage of hitTest, hitTest(x, y, shapeFlag) -- this will not check if two movieclips are hittesting each other, but rather if a MovieClip is touching a POINT (just an x and a y coordinate). But the real advantage of using this is the third parameter, shapeFlag, which is a Boolean value (either true or false) -- if it's false, then the hitTest will take the whole movieclip into account, meaning that even if there are empty spaces, those will be included in the hitTest, WHILE, if it's true, then only the actual shape of the MovieClip will be considered during the hitTest.
First of all, you have to get inside your Character's MovieClip and move him so that the registration point of the movieclip (you know that small plus sign), is at the BOTTOM of your character. Then, change your code to this:
if(_root.ground.hitTest(this._x, this._y, true))
{
this._y -= gravity;
gravity = 0;
jumping = false;
}
This will check if the SHAPE of the ground MovieClip (meaning only the platforms, NOT the empty spaces between them) are touching the registration point of your MovieClip, which is located at the bottom, at the feet, of your character. So, whenever the feet of your character are touching any of the platforms inside the ground movieclip, the code will be executed and your character wil stop.
Hope this helps :)
i'm creating simple iOS game with Cocos2D and Box2D. In my game user has to create full word by shooting to squares with letters. If shooted letter is correct the square should explode, otherwise the square should fall down. I have created simple contact listener and I can detect collision between bullet and square but the problem is how to avoid collision force when letter is incorrect? I that situation (incorrect letter) i want square to simply fall down without applying collision force to the square.
Maybe I can delete the square and create new one at the position of deleted, but i think it's not the best idea :)
One suggestion I would make would be on collision, if the letter is incorrect, set the bodies x and z velocities to 0. This way when they collide with incorrect squares they will simply fall.
Another thing you could do would be to set the target square's body as fixed ( or rigid, I can't remember what it's called in Box2d off the top of my head). So even if an incorrect letter collides with it, it will not budge but the letter will bounce off it. And it the letter is correct, you can explode it as normal.
The solution I would advice is to set the velocity of the bullet to 0 in both directions in the PreSolve callback of the contact listener. Obviously you do a check in the PreSolve function. This way as the function is called PreSolve, the collision calculation have not happened yet. so setting velocity to 0 will make the bullet to have no effect on the square in terms of force.
In my Corona SDK game I would like an item to drop from the sky and bounce up and down a few times before settling, at a randomly designated point on the screen. Say I'll drop an item at X=500 and Y=0. I then designate a drop-off point at Y=700, where the item will drop all the way til Y=700, bounce back up, then down, and after a few times (depending on bounciness), settle down and stay there.
This game is 2.5D, so having a static physics ground at the bottom would not work.
To do this, I came up with two options, neither which worked well:
Make a temporary invisible, 2x1 physics platform at the point where I would want the item to hit and bounce back up and down. This platform is created the moment I drop the item, and deleted when the item has settled down (fell asleep).
Inject force or change the linear velocity when the item passes a certain point.
However, because my gravity has been set to 40 (normal gravity of 9.8 was too floaty), the item will literally vibrate once it has stopped bouncing at the platform, and oscillate between velocities of 20 to -40 (varies) and not go to sleep.
The Injecting force method has also caused weird results, because the code checks the velocites per enterFrame event, so the results are not consistent.
I think the invisible bar is what makes the most sense. I would consider lowering the gravity back to something closer to normal and play with the bounce and density to get the bouncy that you want.
I discovered a lot of new info since I posted this question so I have completely rewritten it:
I have run into some problems while implementing gravity and jumping in my tile-based game.
Sometimes when my character lands between tiles after a jump, the characters falls through them.
The problem certainly is not that my speed is too high since my max speed is the same as my tile-size. Also, the problem does not occur after every time the character jumps. I can often make a jump, get to max velocity, and still land well. But sometimes the character just falls through.
My level exists of layers of tiles. Each layer has it's own collision-type. So every tile in the same layer, follows the same rules for collision.
In my current set-up all layers use per-pixel collision.
This is how I update the player coordinates
http://pastebin.com/qVc6gv6T
This is the class where I calculate my collissions.
http://pastebin.com/7GqrFih6
In the update I just do:
controls.Update(player);
physicsEngine.HandleCollissions(levelManager, player);
I imagine that the problem could be because the player gets moved to another tile after collission. Collides with the other tile. But that doesn't count since the other tile already has been checked for collision?
Or could it be because I use foreach instead of for-loops?
You say the error occurs after jumping. So, your character falls toward a tile (has some positive velocity.Y) and hits it. The collision code executes the // the player comes FROM ABOVE and collides with the tile block. You run a loop that sets player velocity to zero and moves the player out of collision. This loops calls a function using a term tile as an argument. I assume you loop through a set of tiles in order to collide with more than a single square. Am I right?
If I am, then the problem occurs after that first collision and correction. Now your player has a velocity.Y of 0, but they are colliding with a new tile. So in spite of your comment about the meaning of your else block, you may have more position changes happening:
if (player.Velocity.Y > 0)
else // if (moveVector.Y < 0) // what you commented
else // if (moveVector.Y <= 0) // what your else really means
Now sometimes (only when you have slightly mis-alligned per-pixel collisions) you have course corrections happening the the wrong direction. That would produce a fall-through effect. You could try setting a break point in the // the player comes FROM UNDER and collides with the tile block, and then running the program in a scenario that shouldn't cause player.WorldPositionY += 1; to happen. If it happens when it wasn't supposed to, then you have your culprit.
I am doing a lot of speculation here. I think you should post more code so that we can know for sure. But perhaps a paste bin would be appropriate place for it.