How can I do this kind of 3D camera movement in Unity? - c#

This is a school project. I have a big cube which is like a planet. I have a small cube that can move on every side of the cube planet. The player moves forward automatically on its local z axis and I rotate it by 90 or -90 degrees to move left or right- but the player can control it like it's an up-down-left-right movement (made a script so they don't have to rotate the cube with 2 keys). It's like a Tron game so if I press the up key, I can't press down immediately because I leave a trail so I have to press the left or right keys. I have a problem with my camera movement. The camera follows the little cube from above, but I want it to lean a little when the little cube player gets close to the edge of a side so it lets me see the other side - where I'm planning to go.
I have a script where I use the center of the cube planet and the player's center as the direction vector and multiply it with the camera-player distance.
Vector3 direction = (target.position - center.position).normalized;
transform.position = target.position + direction * distance;
Then I point my camera's forward vector to the player cube's direction. I tried two codes but none of them worked perfectly. First I tried to rotate the camera with:
transform.rotation = Quaternion.LookRotation(-direction);
Shown in video. The problem with this is that since I don't tell the program the Up and Right vectors (I think), it sets them for itself to some random numbers so the camera sometimes do its own thing like it does a pirouette.
Next I tried this:
Quaternion rot = Quaternion.FromToRotation(transform.forward, -direction);
transform.Rotate(rot.eulerAngles, Space.World);
Shown in video. It's almost good but as the little cube moves, the camera starts steering slightly in the beginning and it gets worse and worse.
Do you have any ideas how can I make it work? I hope you understand what I would like to achieve. I'm trying to set the camera as to always show that when I press Up, my cube moves upward, when I press Right my cube always goes right etc. and when I reach the edge of my side the camera leans a bit towards the side I'm moving to.

Use dot product to find which orthogonal direction of your cube is closest to the camera's current up.
Vector3 closestToUp;
float greatestDot = 0f;
foreach (Vector3 dir in new Vector3[]{
target.forward, target.right, -target.forward, -target.right})
{
float curDot = Vector3.Dot(dir,transform.up);
if (curDot > greatestDot)
{
greatestDot = curDot;
closestToUp = dir;
}
}
Than, use that direction as the second parameter of Quaternion.LookRotation. This will keep its local up direction as aligned with the cube's "top" as possible given whatever new forward direction:
transform.rotation = Quaternion.LookRotation(-direction, closestToUp);

Related

Problem with 3rd person camera rotation in unity

I'm trying to make the camera rotate around an object according to the movement of the mouse, and this is what I've come up with:
void Start()
{
direction = new Vector3(1f,0f,0);
direction.Normalize();
Debug.Log(direction);
mousePosCurr = Input.mousePosition;
}
void Update()
{
mousePosPrev = mousePosCurr;
mousePosCurr = Input.mousePosition;
mouseVector = (mousePosCurr - mousePosPrev);
mouseVector = mouseVector * sensitivity;
direction = Quaternion.Euler(mouseVector.y, mouseVector.x, 0) * direction;
direction.Normalize();
Debug.Log(direction);
this.transform.position = (target.position + tOffset + (direction * distance));
transform.LookAt(target.position + tOffset, Vector3.up);
}
Now, I'm sure that there are at least a million problems with this code, however the main one I'm facing right now is that the x rotation does not work correctly, unless the y rotation is in a specific direction.
What's happening is basically that the more I rotate in the y axis the more "inprecise" the x movement becomes. So for example, when the camera is south of the object I'm rotating it around, the x rotation works exactly as it should, you move the mouse up, and the camera points up and viceversa, but when it's west of it the movement of the mouse required for the vertical rotation is no longer vertical, but diagonal, and when it's north of the object the movement is inverted: moving the mouse up makes the camera point down and viceversa.
This seems most likely caused by the fact that regardless of the horizontal rotation of the direction vector, I'm still rotating along the x axis in the same direction, as if the camera was south of the object.
However, even having (hopefully) identified the problem, I'm still clueless as to how to solve it, so I'm asking for help here.
Note: I just noticed that I probably used the term "rotation" wrong in this post. When I write "rotation of the camera", I'm actually referring to the rotation of the "direction" vector.
alright so I am not the best in Unity so this might be completely useless but when I try to rotate my camera around an object I create an empty game Object and make the camera a child of it, like this
so that I can just just rotate the Game Object to rotate the camera around a fixed point maybe your code will work

Make GameObject's Y Rotation be the same as the camera's

I have a Cinemachine Freelook camera and i want it similar to Skyrim, where the character's rotation follows where the camera is pointing, but only on the Y axis so that i can move my mouse and look at the character from up and down;
This video demonstrates how MrKrabs can move in 3 dimensions, but won't turn.
I already tried creating a blank object and putting it at the center of the character, then using transform.LookAt(Camera) to make it point to where the camera is, and finally getting the Y value of the object's rotation, inverting it with -transform.position.y and applying it to MrKrabs, but it didn't work: it was jittery and overall just a bad user experience, is there a way to turn the gameobject based on the camera's rotation? (having the camera always watching his back)
Something like this should do the trick.
transform.rotation = Quaternion.Euler(0, Camera.main.transform.eulerAngles.y, 0);
Beware that if your camera is a child of your object it will rotate with it.

Control player z axis with mouse x axis

I'm trying to move the player to the position of the mouse in my game.
Right now movement along the x axis works fine, but I want the mouse y axis to control the characters movement along the z axis (because of my top-down camera's y being world z).
Right now mouse y controls player y, which looks like this in game.
And the code for it looks like this:
public Vector2 mousePos;
private Vector3 playerPos;
void update()
{
// Get mouse position from player
mousePos = Input.mousePosition;
// Move player with mouse
playerPos = new Vector3(mousePos.x, 0, mousePos.y);
transform.position = Camera.main.ScreenToWorldPoint(playerPos);
}
I then tried to just swap the y and z like this
playerPos = new Vector3(mousePos.x, mousePos.y, 0);
But instead of allowing me to control the z axis this snippet instead causes the player to lose all movement.
I'm very new to coding so I might be missing something completely obvious. What am I doing wrong?
Unity version: 2018.4.21f1
The example you gave isn't working because you're providing a z coordinate of 0 and when called on a perspective camera, Camera.ScreenToWorldPoint does some vector math, so in your scene view, your player is probably floating right on top of your camera. I can't explain the actual math because I don't understand it, but luckily for both of us, we don't need to! Essentially, the z coordinate is saying how far away from the camera to place the point, and since the view frustum of a perspective camera gets narrower closer to the camera, placing it at 0 means there's nowhere for it to go. how moving the object farther from the camera requires it to move farther to match the mouse position.
The bigger problem is that your method is wrong and there's a better way. Camera.ScreenToWorldPoint converts a mouse coordinate to a world space coordinate depending on what the camera is looking at, so you're essentially flippng the y and z coordinate, then feeding it into a method that figures out what coordinates need to be flipped.
It looks like this script is attached to your player gameObject, so it should look like this:
Camera cam;
[Range(1,10)] //this just creates a slider in the inspector
public int distanceFromCamera;
void Start()
{
//calling Camera.main is a shortcut for
//FindGameObjectsWithTag("MainCamera")
//so you should avoid calling it every frame
cam = Camera.main;
}
void Update()
{
//This will work for both perspective and orthographic cameras
transform.position = cam.ScreenToWorldPoint(
Input.mousePosition + new Vector3(0,0,distanceFromCamera));
}
If your camera is going to move closer or farther from the plane, make sure to add something that keeps the distance from camera updated.
That said, for most games having the player tied to the mouse cursor isn't usually what you're looking for. Generally you want some kind of input to move the player in some direction a certain amount. If that's what you're looking for, this part of the space shooter tutorial is a good introduction to player movement (though the code itself may be outdated).

How to rotate around a corner when the distance is unknown

I feel like this is a solvable problem but I am just to stupid to solve it.
I want to able to move a player around a cube in third person in a 3D game. Before I worry about the corners where 3 edges of the cube meet I would first like to be able to move around two edges. If I use the LookAt method while jumping around a corner some problems occur with the vertical rotation of the player. So if he enters the trigger of the edge he turns around 180 degree somehow. That is why I am searching for a different solution.
(Green rectangle is the player. The dotted area is a trigger.)
So what I am given on the entry of the trigger is the edge position P2 and obviously the player position P3. The player should be able to stop the velocity while being mid air, so he could just fall down to the edge thanks to the gravity. That means that I can not just lerp it from the entry point to some exit point. The entry and exit points are dynamic.
What I already calculated is the distance from the player to the edge. Therefore I could tell if the player is closer to the right surface or the left surface judging by whether X or Y is higher.
But if the player enter on a higher position the numbers are also higher.
I am very confused about how to solve this. I need to lerp rotate the player around the corner P2 as long as he is within the two dotted lines.
Here's something to get you started. This will rotate your player so that their down is pointing at the edge, and their forward vector tries to remain unchanged as much as possible. This will mean that moving in playerTransform.forward will move them where they are facing but will rotate them so that as they move around the edge, they will rotate around it.
transform playerTransform;
Vector3 edgeWorldDirection;
Vector3 edgeWorldPosition;
Vector3 playerWorldPosition;
// Determine up direction
Vector3 player2Edge = edgeWorldPosition - playerWorldPosition;
Vector3 playerUpDirection = (
Vector3.Dot(player2Edge, edgeWorldDirection) * edgeWorldDirection
- player2Edge).normalized;
// rotate player to align local up with playerUpDirection and forward with
// previous forward as much as possible.
Vector3 playerRightDirection = Vector3.Cross(playerUpDirection, playerTransform.forward);
// handle player looking "up"
if (playerRightDirection == Vector3.zero) playerRightDirection = player.Transform.right;
Vector3 playerForwardDirection = Vector3.Cross(playerRightDirection, playerUpDirection);
playerTransform.rotation = Quaternion.LookRotation(playerForwardDirection, playerUpDirection);
For corners it's actually easier because your up is based on the location of the corner, you don't have to calculate the closest point on a line.
transform playerTransform;
Vector3 cornerWorldPosition;
Vector3 playerWorldPosition;
// Determine up direction
Vector3 playerUpDirection = (playerWorldPosition - cornerWorldPosition).normalized;
// rotate player to align local up with playerUpDirection and forward with
// previous forward as much as possible. Same logic here as previously.
Vector3 playerRightDirection = Vector3.Cross(playerUpDirection, playerTransform.forward);
// handle player looking "up"
if (playerRightDirection == Vector3.zero) playerRightDirection = player.Transform.right;
Vector3 playerForwardDirection = Vector3.Cross(playerRightDirection, playerUpDirection);
playerTransform.rotation = Quaternion.LookRotation(playerForwardDirection, playerUpDirection);
Depending on how you're handling movement & player orientation, you may not actually want to rotate the player's transform, but with the results of Quaternion.LookRotation(...) you can multiply the local direction the player tries to go by that rotation to get the world direction that would correspond to.:
Vector3 localDesiredMove;
Quaternion boxOrientationQuat = Quaternion.LookRotation(
playerForwardDirection,
playerUpDirection);
Vector3 worldBoxOrientedMove = boxOrientationQuat * localDesiredMove;

XNA Monogame Mouse Projectile Click

I am coding for a game and I have it running fine and all, but I ran into the issue of projectiles. I have no idea of how to calculate the mouse position and send a projectile over. I've looked though many stackoverflow tutorials and many youtube videos, but they are either too vague or very very complex. Could someone please explain the process? I have been coding in C# for 2 years now, so I do have background knowledge. Please Help!
Well, you don't tell what kind of game you are working on and what the projectile you want to "send over", whatever that means but here are a few pointers, maybe one will help:
#1: If you are doing a 2D game, and you want to send a projectile from some point toward the mouse cursor, then you simply get the position of the mouse by calling GetState() on your MouseState instance, and reading it's X and Y properties, then get the direction of the projectile by subtracting the location of the origin of the projectile from the mouse position. Then you can move the projectile along that line by storing the time you launched it, subtracting that every frame from the actual time to get how long it has been on its way and then adding that many times it's speed times the normalized direction to its origin coordinates.
Example:
For this I assume you have a Projectile class that has Vector2 field called origin, one called direction, one called position, a float called speed and an int called startTime and you have an instance of it with origin and speed already set. Modify as necessary for your actual code.
MouseState ms = new MouseState();
in your Update method:
ms.GetState();
projectile.direction = new Vector2(ms.X, ms.Y) - projectile.origin;
projectile.direction.Normalize();
projectile.position = projectile.origin + projectile.speed * (gameTime.TotalGameTime.TotalMilliseconds - projectile.stratTime) * projectile.direction;
And then in the Draw method you just draw the projectile to the coordinates in projectile.position.
#2: You are doing a 3D game and want to shoot a projectile originating from your camera and directed toward whatever your mouse is pointing at. You will need to generate a Ray with something like this:
private Ray getClickRay(Vector2 clickLocation, Viewport viewport, Matrix view, Matrix projection)
{
Vector3 nearPoint = viewport.Unproject(new Vector3(clickLocation.X, clickLocation.Y, 0.0f), projection, view, Matrix.Identity);
Vector3 farPoint = viewport.Unproject(new Vector3(clickLocation.X, clickLocation.Y, 1.0f), projection, view, Matrix.Identity);
Vector3 direction = farPoint - nearPoint;
direction.Normalize();
return new Ray(nearPoint, direction);
}
From there you can get the position of your projectile the same way as above, only using Vector3-s instead of Vector2-s.
#3: You want to simulate some sort of launcher and do a physical simulation on the trajectory of the projectile. Since I find this less likely than the first two I'll just describe the idea: you set a minimum and maximum rotation for your launcher along 2 axes, link each rotation to the ratio of the full width and length of your screen to the mouse position, and then use the angles and whatever other variables you have to calculate the direction and speed of the projectile at launch, then simulate physics each frame.
I hope one of these will help.

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