Develop Reference

Rotating field of view with player

So I have trying to create a system that looks for a ledge to climb. I have a vertical field of view that looks for these ledges and I have, so far, got it to rotate with the analogue stick's direction, so I can find a ledge and move to it where my analogue is pointing. (Look up, find ledge, move up, etc). My problem is, while the the field of view moves where I need it to move, it stays fixed on one axis and does not rotate with the player.
In the picture the cone is facing where it should be, and rotates around the player as I want it to, but as you can see, the cone faces the X-Axis and does not move from there. I want it to rotate with the player.
In the below code, the returned Vector's y value makes the cone point upwards. I have tried all manner of functions in the x and z values, but nothing is sticking.
public Vector3 DirFromAngle(float angleInDegrees, bool angleIsGlobal)
{
if(!angleIsGlobal)
{
angleInDegrees += (viewDir + 90);
}
Vector3 newValue = new Vector3(0, Mathf.Sin(angleInDegrees * Mathf.Deg2Rad), Mathf.Cos(angleInDegrees * Mathf.Deg2Rad));
return newValue;
}
The viewDir value makes the cone rotate with my analogue stick, to make the cone rotate with my player, I assume that something needs to be done with either the x or z values, or both, but for the life of me, I can't figure it out.
Thank you for any help on this issue. Apologies if my explanation isn't very good.
void OnSceneGUI()
{
LedgePointSearch lps = (LedgePointSearch)target;
Handles.color = Color.white;
Handles.DrawWireArc(lps.transform.position, lps.transform.forward * 90, Vector3.up, 360, lps.viewRadius);
Vector3 viewAngleA = lps.DirFromAngle(-lps.viewAngle / 2, false);
Vector3 viewAngleB = lps.DirFromAngle(lps.viewAngle / 2, false);
Handles.DrawLine(lps.transform.position, lps.transform.position + viewAngleA * lps.viewRadius);
Handles.DrawLine(lps.transform.position, lps.transform.position + viewAngleB * lps.viewRadius);
}
This is the editor script that displays the field of view.
The circle simply represents the radius of the field of view, how far it goes out.
https://www.dropbox.com/s/k9siha2aog9vj8o/fov.mp4?dl=0
In the video, the circle rotates with the player, and the cone rotates with my left analogue movements. I want the cone to be like the circle, with it rotating as my player does, but still matching my analogue movements.

One way to approach this is to find the Y rotation of the player and apply it to newValue before returning it.
public Vector3 DirFromAngle(float angleInDegrees, bool angleIsGlobal)
{
if(!angleIsGlobal)
{
angleInDegrees += (viewDir + 90);
}
Vector3 newValue = new Vector3(0, Mathf.Sin(angleInDegrees * Mathf.Deg2Rad), Mathf.Cos(angleInDegrees * Mathf.Deg2Rad));
// get Y rotation of player
yRotationAngle = player.transform.rotation.eulerAngles.y;
// convert to Quaternion using only the Y rotation
Quaternion yRotation = Quaternion.Euler(0f, yRotationAngle + 90f, 0f);
// Apply yRotation
newValue = yRotation * newValue;
return newValue;
}

MonoGame/XNA rotating an image

This code is to draw the tower. Square locations are the top left of the square. TILE_SIZE is simply the dimensions of the square.
SpriteBatch.Draw(TowerImage, new Rectangle(square.X * TILE_SIZE, square.Y * TILE_SIZE, TILE_SIZE, TILE_SIZE), null, Color.White, myTower.Rotation,
new Vector2(TILE_SIZE - 35, TILE_SIZE - 35), SpriteEffects.None, (float)0.0);
This code is how I determine the rotation
public void FaceTarget(Vector2 center, Vector2 enemyCenter)
{
Vector2 direction = center - enemyCenter;
direction.Normalize();
this.Rotation = (float)Math.Atan2(-direction.X, direction.Y);
}
I did this based on:
http://www.riemers.net/eng/Tutorials/XNA/Csharp/Series2D/Rotation.php
http://www.riemers.net/eng/Tutorials/XNA/Csharp/Series2D/Direction_to_Angle.php
The rotation is being really weird, here is how it looks normally:
But when it rotates it goes like this:
Finally when it looks down, it goes complete off path, it's not rotating by its center, but the entire image is moving why is it doing that?
Only the first image is actually the tower in the correct position
It seems like it is rotating of the top left point and I don't know why. Can anyone help?

Apparently, your sprite is taking into consideration as the origin of rotation a Vector2.Zero (or Vector2(0,0)) point. That means the upper left point of the Texture2D file.
I see that you are setting the origin in the Draw method to TILE_SIZE - 35 which makes me wonder, is the tile a square of 70 pixels W/H?
What happens if you replace the substraction with new Vector2(TowerImage.Width / 2, TowerImage.Height / 2)?
I'll leave you an example from this site which explains easily how to rotate an image following the mouse position at all times:
Update method:
MouseState mouse = Mouse.GetState();
mousePosition = new Vector2(mouse.X, mouse.Y);
Vector2 direction = mousePosition - position;
direction.Normalize();
rotation = (float)Math.Atan2(
(double)direction.Y,
(double)direction.X);
Draw method:
spriteBatch.Begin();
spriteBatch.Draw(
rocket,
position,
null,
Color.White,
rotation,
new Vector2(
rocket.Width / 2,
rocket.Height / 2),
1.0f,
SpriteEffects.None,
1.0f);
spriteBatch.End();
Check that in the posted code the rotation angle is calculated slightly different than yours, but the important piece of code is the calculation of the origin point in the Draw method.

Make a point follow a rotating sprite

I have a rectangle with a square at its bottom. I also have code that makes the rectangle rotate around its origin which is at the top of this rectangle. Im trying to make the square at the bottom to always stay at the end of this rectangle even when its rotated. Hers a picture to illustrate my problem:
I see now that it wasn't such a good idea to make the square at the bottom white. So when i rotate the rectangle upwards to the right or upwards to the left, I want the square to keep staying at the end of this rectangle. Maybe there is a simple solution, but my knowledge isn't as good as it should be on this subject. Hope someone could point me in the right direction.

Something like this aught to get you there.
float pendulumAngle;
Vector2 origin;
Vector2 squareTLcorner;//top left corner of square
Vector2 squareOffset;
void Reset()
{
pendulumAngle = 0;
origin = new Vector2(?.?f, ?.?f);// set to whatever you need
squareTLcorner = new Vector2(?.?f, ?.?f); // set to whatever you need
squareOffset = squareTLcorner - origin;
}
void UpdatePendulum(float angleMovedSinceLastFrame)
{
pendulumAngle += angleMovedSinceLastFrame;
}
void UpdateSquarePosition()
{
squareTLcorner = Vector2.Transform(squareOffset, Matrix.CreateRotationZ(pendulumAngle) + origin;
}
void DrawSquare()
{
spriteBatch.Draw(sqTex,squareTLcorner, , ,pendulumAngle, , , , );// overload 6 of 7
}

The easiest way is passing a transformation matrix to the sprite batch.
Rectangle Black = new Rectangle(0,0, 20, 100);
Rectangle White = new Rectangle( Black.Left, Black.Bottom, Black.Width, Black.width);
Vector2 Pivot= new Vector(100,100);
vector2 Origin = new Vector2( 10,10);
Matrix transform = Matrix.CreateTranslation(-Origin.X, -Origin.Y)
* Matrix.CreateRotationZ(angle)
* Matrix.CreateTranslation(Pivot);
SpriteBatch.begin(...., transform)
SpriteBatch.Draw( Texture, Black, Color);
SpriteBatch.Draw( Texture, White, Color);
SpriteBatch.end();
Basically you are working in a different space that is rotated ans translated as you need, realize that Black rectangle location is (0,0).
Code it's not tested but should work as expected. ;)

Positioning situation in XNA

I've been trying to fix this problem, but I have no idea. I know before I've asked about origin, but I don't really know how to fix this.
red dot = coordinates x-y
yellow dot = origin used in spritebatch.draw
origin = new vector(img.width/2, img.height/2);
position = new rectangle(400, 200, img.width, img.height);
center_x = position.center.x
center_Y= position.center.y
I noticed that even though I placed the origin when using spritebatch.draw, the positioning is still done from the 0,0 origin instead of the Yellow dot. How can I change this? I noticed it when I check both the center for Y and X on the position rectangle and compared it with the actual coordinates. The center was higher than the coordinates its self. I want it so that the center coordinates are the same from the position's X & Y. Example, I assign 200 for X and 200 fro Y in the position rectangle. When I go check the center of that rectangle, I want it to be 200 on both X and Y. Also, I'm using a rectangle for positioning cause I'm also testing out so collision stuff.
An example would be nice, thanks in advance

You are passing to positioning a rectangle, use a Vector2 to positioning instead:
Vector2 origin = new Vector2(img.Width, img.Height) * 0.5f;
Vector2 pos = new Vector2(400,200) + origin;
spriteBatch.Draw(img, pos, null, Color.White, 0, origin, SpriteEffects.None, 0)
This works for sure.
EDIT:
if you want to work with rectangles be sure that origin is related to the texture size.
Rectangle bounds = new (400,200, img.Width, img.Height);
Vector2 origin = new Vector2(img.Width, img.Height) * 0.5f;
spriteBatch.Draw(img, bounds, null, Color.White, 0, origin, SpriteEffects.None, 0)
This works too.
The position of the yellow dot will be (400,200)
if you don't use origin, the red dot position will be (400,200)

i don't see position on our example of spriteBatch. try using it with all properties.
SpriteBatch.Draw (Texture2D, ImgPosition, ImgRect, ImgColor, ImgRotate, ImgOrigin, Scale, SpriteEffects, Layer)
http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.graphics.spritebatch.draw.aspx

If you're trying to draw a sprite setting its Origin in its center you're doing it right. Your yellow dot is at position (400, 200) and the dot in the screenshot is reasonably in that position, considering the screen dimension of 800x480. But if you want that the upperleft corner of your sprite has that position you need to change your Draw call.
When specifying the Origin, try using Vector2 position instead of Rectangle for the second parameter of Draw to set the positin of your sprite.
Specify Vector2 Position and Origin:
origin = newVector2(img.Width, img.Heigth) / 2;
pos = new Vector2(400, 200) + origin;
spriteBatch.Draw(img, pos, null, Color.White, 0, origin, SpriteEffects.None, 0);
Or use only the position Rectangle:
posRect = new Rectangle(400, 200, img.Width, img.Heigth);
spriteBatch.Draw(img, posRect, Color.White);

Rotate a Texture2D with the Draw method in XNA?

I have a problem with rotating. I know that I can rotate a Texture2D object with the draw method.
My goal is to rotate a texture by 180°. For example, if I make a picture of a human with the camera where the head is at the bottom, I want to be able to rotate it so that the head is at the top again.
Here is the code or the rotation:
spriteBatch.Draw(Texture, Position, null, Color.White, MathHelper.Pi, new Vector2(), 1.0f, SpriteEffects.None, 0f);
The rotation works fine, but I have another problem:
If I add the texture to position 0,0 after rotating it, it's not visible anymore.
How do I rotate or maybe reflect the object, so that the red point will be at the top-left corner again?

http://msdn.microsoft.com/en-us/library/ff433989.aspx
public void Draw (
Texture2D texture,
Vector2 position,
Nullable<Rectangle> sourceRectangle,
Color color,
float rotation,
Vector2 origin,
Vector2 scale,
SpriteEffects effects,
float layerDepth)
//Using:
var origin = new Vector2()
{
X = texture.Width / 2,
Y = texture.Height/ 2
};
spriteBatch.Draw(texture, Vector2.Zero, null, Color.White, MathHelper.Pi, origin, 1f, SpriteEffects.None, 0f)`