BizHawk/Bizware/BizHawk.Bizware.BizwareGL/MatrixStack.cs

89 lines
4.0 KiB
C#

using System.Drawing;
using System.Collections.Generic;
using OpenTK;
namespace BizHawk.Bizware.BizwareGL
{
//note: the sense of these matrices, as well as pre- and post- multiplying may be all mixed up.
//conceptually here is how we should be working, in the example of spinning a sprite in place
//1. sprite starts with top left at origin
//2. translate half size, to center sprite at origin
//3. rotate around Z
//4. translate to position in world
//this class is designed to make that work, that way. the takeaways:
//* Use the scale, translate, rotate methods in the order given above
//* Use PostMultiplyMatrix to apply more work to a prior matrix (in the manner described above) since I am calling this all post-work
public class MatrixStack
{
public MatrixStack()
{
LoadIdentity();
IsDirty = false;
}
public static implicit operator Matrix4(MatrixStack ms) { return ms.Top; }
public static implicit operator MatrixStack(Matrix4 m) { return new MatrixStack(m); }
public MatrixStack(Matrix4 matrix) { LoadMatrix(matrix); }
public bool IsDirty;
readonly Stack<Matrix4> stack = new Stack<Matrix4>();
/// <summary>
/// This is made public for performance reasons, to avoid lame copies of the matrix when necessary. Don't mess it up!
/// </summary>
public Matrix4 Top;
/// <summary>
/// Resets the matrix stack to an empty identity matrix stack
/// </summary>
public void Clear()
{
stack.Clear();
LoadIdentity();
IsDirty = true;
}
/// <summary>
/// Clears the matrix stack and loads the specified value
/// </summary>
public void Clear(Matrix4 value)
{
stack.Clear();
Top = value;
IsDirty = true;
}
public void LoadMatrix(Matrix4 value) { Top = value; IsDirty = true; }
public void LoadIdentity() { Top = Matrix4.Identity; IsDirty = true; }
public void Pop() { Top = stack.Pop(); IsDirty = true; }
public void Push() { stack.Push(Top); IsDirty = true; }
public void RotateAxis(Vector3 axisRotation, float angle) { Top = Top * Matrix4.CreateFromAxisAngle(axisRotation, angle); IsDirty = true; }
public void Scale(Vector3 scale) { PreMultiplyMatrix(Matrix4.CreateScale(scale)); IsDirty = true; }
public void Scale(Vector2 scale) { PreMultiplyMatrix(Matrix4.CreateScale(scale.X, scale.Y, 1)); IsDirty = true; }
public void Scale(float x, float y, float z) { PreMultiplyMatrix(Matrix4.CreateScale(x, y, z)); IsDirty = true; }
public void Scale(float ratio) { Scale(ratio, ratio, ratio); IsDirty = true; }
public void Scale(float x, float y) { Scale(x, y, 1); IsDirty = true; }
public void RotateAxis(float x, float y, float z, float degrees) { PreMultiplyMatrix(Matrix4.CreateFromAxisAngle(new Vector3(x, y, z), MathHelper.DegreesToRadians(degrees))); IsDirty = true; }
public void RotateY(float degrees) { PreMultiplyMatrix(Matrix4.CreateRotationY(MathHelper.DegreesToRadians(degrees))); IsDirty = true; }
public void RotateX(float degrees) { PreMultiplyMatrix(Matrix4.CreateRotationX(MathHelper.DegreesToRadians(degrees))); IsDirty = true; }
public void RotateZ(float degrees) { PreMultiplyMatrix(Matrix4.CreateRotationZ(MathHelper.DegreesToRadians(degrees))); IsDirty = true; }
public void Translate(Vector2 v) { Translate(v.X, v.Y, 0); IsDirty = true; }
public void Translate(Vector3 trans) { PreMultiplyMatrix(Matrix4.CreateTranslation(trans)); IsDirty = true; }
public void Translate(float x, float y, float z) { PreMultiplyMatrix(Matrix4.CreateTranslation(x, y, z)); IsDirty = true; }
public void Translate(float x, float y) { Translate(x, y, 0); IsDirty = true; }
public void Translate(Point pt) { Translate(pt.X, pt.Y, 0); IsDirty = true; }
public void PostMultiplyMatrix(MatrixStack ms) { PostMultiplyMatrix(ms.Top); IsDirty = true; }
public void PostMultiplyMatrix(Matrix4 value) { Top = value * Top; IsDirty = true; }
public void PreMultiplyMatrix(Matrix4 value) { Top = Top * value; IsDirty = true; }
}
}