recrownedgtk/RecrownedAthenaeum/Render/Camera2D.cs

86 lines
3.2 KiB
C#

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System;
namespace RecrownedAthenaeum.Render
{
/// <summary>
/// A virtual 2D camera that wraps the normal <see cref="BasicCamera"/>. Default projection is orthographic.
/// </summary>
public class Camera2D : BasicCamera
{
/// <summary>
/// The width of the view of the camera.
/// </summary>
public int viewWidth;
/// <summary>
/// The height of the view of the camera.
/// </summary>
public int viewHeight;
/// <summary>
/// The 2D position.
/// </summary>
public Vector2 Position { get { return new Vector2(position.X, position.Y); } set { position.X = value.X; position.Y = value.Y; } }
/// <summary>
/// Places camera in the center given the corner position.
/// </summary>
public Vector2 ConrnerPosition { set { position.X = value.X + viewWidth / 2f; position.Y = value.Y + viewHeight / 2f; } }
/// <summary>
/// A 2D camera from the generic <see cref="BasicCamera"/>.
/// </summary>
/// <param name="height">Width of camera view.</param>
/// <param name="width">Height of camera view.</param>
/// <param name="basicEffect">A basic effect that will be updated with the correct matrice information everytime <see cref="Apply"/> is called. Can be null and thus will not be used.</param>
public Camera2D(int width, int height, BasicEffect basicEffect = null) : base(basicEffect)
{
this.viewWidth = width;
this.viewHeight = height;
upDirection = Vector3.Down;
ConrnerPosition = new Vector2(0, 0);
Apply();
}
/// <summary>
/// Applies for 2D.
/// Sets where the camera is looking for the view matrix to the position of the camera.
/// </summary>
public override void Apply()
{
projectionMatrix = Matrix.CreateOrthographic(viewWidth, viewHeight, 0, 1);
position.Z = 0;
lookAt = new Vector3(Position, 1f);
base.Apply();
}
/// <summary>
/// Lerps to the given position.
/// </summary>
/// <param name="alpha">The multiplier for difference in distance.</param>
/// <param name="targetPosition">The target position to lerp to.</param>
/// <param name="delta">Time between this frame and the previous frame.</param>
public void LinearInterpolationToPosition(float alpha, Vector2 targetPosition, float delta)
{
if (alpha <= 0 && alpha > 1f) throw new ArgumentException("Alpha can't be greater than 1f, less than or equal to 0.");
Vector2 distance = targetPosition - Position;
distance *= (float)(1.0f - Math.Pow(1 - alpha, delta / 0.02f));
Position += distance;
}
/// <summary>
/// Moves the camera.
/// Apply needs to be called.
/// </summary>
/// <param name="move">Magnitude of how much to move per axis.</param>
public void MoveCamera(Vector2 move)
{
Position += move;
}
}
}