Tracking 3D cube position OpenGL? - iphone

SHORT INTRO:
I'm having trouble with a 3D cube on a plane. The plane is a grid of squares. The ID number of the square that the cube currently occupies on is stored in a storage-variable. This is so that I can tell whether or not adjacent squares are free for the cube to move onto. When I move the cube, the storage-variable is updated to reflect the ID number of the new square.
PROBLEM:
The problem is that sometimes when I am moving the cube, the cube is moved too far or in the wrong direction and the square in the storage-variable does not match the actual square the cube is drawn on...This causes problems like the cube not detecting collisions and even going through objects it is not supposed to....
Cube is drawn in a drawView method in an iPhone OpenGL ES EAGLView at a rate of 24 times per second...Could the fast drawing be the cause of this???? How can I fix this? My job depends on it...
Somebody please help.

Well, not a lot to go on... But I doubt that the display refresh rate has any bearing on where the cube is going. Sounds like you have a good old fashioned logic error. But again, that's only going off what you've given.

Have you tried checking to make sure each storage-variable maps correctly onto each square in your plane? Try debugging, drawing a square at a time to make sure it's drawing each one where you think it's supposed to be.

Related

Why can I see the inside of a room as soon as I cross it, in Unity?

I am currently working on a 3d game in Unity, and I am working on the level design using ProBuilder. I basically created a huge cube which I "flipped normal", and a second one way smaller
which, as the other one, I flipped normal, but as soon as I crossed it while turning backward I could weirdly see through the small cube, which makes it feel unfinished. How could I fix this issue?
Normally in 3d games triangles can only be seen from one side. Usually this is not a problem because walls have some thickness. Since you clearly have paper thin walls made of only one layer of triangles this is exactly the result you should expect.
In short add the other side to your walls. The simples way is to duplicate the existing triangles and flipping them. Walls will still be paper thin of course. Later you should probably make them thicker.

How to make a terrain that acts like the globe?

I want to make a terrain where the ending point is also the starting point. So, like on the earth you could just go on walking straight and you would reach the point where you started again after some time.
Thanks for your help!
Unity's Terrain system can only create square regions of terrain. So this can't be done as such.
However, you can approximate it, and I'll tell you how I've done it in my project to some success.
Figure out how much terrain you need to cover the "globe", we'll say it takes NxN chunks of terrain we'll call a "tile".
What you do next is you make 9 of those NxN tiles, and arrange them in a 3x3 grid. Put the camera in the center tile of the grid, and whenever the camera leaves that tile, determine where it is on the tile it is on, then change its position to the corresponding position on the center tile.
This will give you a "toroidal" world. I found this was the easiest solution to get the player to see things on the other "corner" of the world map, and then cross into it without graphical issues.
If you have other objects residing on the world, that presents some additional challenges. One thing you can start with is duplicating them 9x and start them at the same relative position of each tile. If they only interact with the player, that should be fine, just whenever the player interacts with 1, the other 8 do whatever that 1 does.
If the other residents of the globe have to interact with each other, you'll need a way to figure out how to make all 9 copies of everything behave consistently, but that's too broad of a question to address here.

Infinite plane background

How would i go about creating as a background for a 3d scene a plane with a texture that stretches into the horzon? I have tried a skybox but i think a skybox will also be needed "behind" the infinite plane.
It depends whether you need to have an actual geometry that will be seen from close up - if not, you can bake it into the skybox.
In some cases (i.e. when the user has stereoscopic display on their head) you will need to have actual geometry.
Its not exactly clear from your question if you want to create a 'floor' or a 'wall', but in both cases I would link it with player position somehow. A floor could follow players X an Z, while a 'wall' could be made a child to the camera, this way it would never leave the viewport.
Skybox would still be the cheapest by a significant margin, we can give more advice if you provide some additional information. i.e. what are you trying to achieve

How to roll a cube on it's edges on Unity 3D

I want to move a cube by making it roll on it's edges. The cube will be standing on a x-z grid and each movement it takes will make it stand on a different square of the grid.
The player will controll the movement and will only be able to make the cube roll on one direction at a time (left, right, forward or back), but the cube must always stand exactly on top of one of the grid's squares.
I don't think applying a force to the cube will help cause it could move it a little bit too much or too little. I want to achieve something like this: https://www.youtube.com/watch?v=yaAIUYuNi84 but only on the x-z plane. Notice how on each corner the cube can stop and change direction with ease, because it never moves too much or too little.
Any ideas on how to approach this?
If you are new to the Unity it will be useless to trowing you a bunch of codes so i am telling you the way of doing it so you can implement your own codes.
You can create 4 empty game object which will always follow the cube on the floor and when you want to roll the cube you will rotate the cube around the empty objects.
You can find the codes for following the cube and rotating the cube on youtube, and for the starters searching is allways good.
So i hope you can manage it out, if you cant please write me again where did you stuck and i will be happy to answer you :)

How to override physical marker in vuforia AR Camera in runtime?

How can I override the physical marker in unity to just make the physical marker invisible in camera while detecting any object.
Like in this video:
https://m.youtube.com/watch?v=R_F1LvK5gCk
And many other videos.
This maybe isn't the correct answer but, I'll put my ideas here because sadly it doesn't fit in the comment section.
I just watch the video and some of the reels they show as his works.
First, yes, in deed they make the marker a sort of invisible marker, but if you look closely, like a 0.25 speed and pushing space bar very fast to look it in slowmo, you can see a kind of "artifact" in between the girl's fingers that makes me think there's no invisible marker but a texture that are covering the marker. Maybe a cylinder that gets his texture from the video camera input.
Now, how I do that?
There are several ways to get the pixels from the webcamera, even Unity has one function. The trouble is, I dont want all the pixels but a little tiny part of the camera render, specifically the one's around my marker.
In my experience, and in his examples, they are using OpenCV, another unity plugin, so they can track anything, from faces, hands, or markers, so I can't be quite sure they are using Vuforia alone or in combination.
My idea is, with OpenCV you can catch your marker and his contour, then ask for the pixels outside the contour of your marker, those pixels will be the skin tone of the person and latter apply them as a texture over some plane or 3d model that can cover your marker. You can have the pixels at right side and left side of the marker and use a average function betwen them so it could look nice or if you like the adventures you can try to use some kind of digital images processing method to get bether results.
I'm not sure if you can have the pixels arround a marker just using just Vuforia. Honestly I've never try it before.
Well, that's my idea.
If you can get it better I'll like to hear about it.