Rectangle2D.cs :  » Game » RealmForge » Axiom » Graphics » C# / CSharp Open Source

using System;
using Axiom.Core;
using Axiom.Graphics;
using Axiom.MathLib;

namespace Axiom.Graphics{
  /// <summary>
  ///    Allows the rendering of a simple 2D rectangle
  ///    This class renders a simple 2D rectangle; this rectangle has no depth and
  ///    therefore is best used with specific render queue and depth settings,
  ///    like <see cref="RenderQueueGroupID.Background"/> and 'depth_write off' for backdrops, and 
  ///    <see cref="RenderQueueGroupID.Overlay"/> and 'depth_check off' for fullscreen quads.
  /// </summary>
  public class Rectangle2D : SimpleRenderable {

    const int POSITION = 0;
    const int TEXCOORD = 1;

    static float[] texCoords = new float[] {0, 0, 0, 1, 1, 0, 1, 1};

    public Rectangle2D() : this(false) {}

    public Rectangle2D(bool includeTextureCoordinates) {
      vertexData = new VertexData();
      vertexData.vertexStart = 0;
      vertexData.vertexCount = 4;

      VertexDeclaration decl = vertexData.vertexDeclaration;
      VertexBufferBinding binding = vertexData.vertexBufferBinding;

      decl.AddElement(POSITION, 0, VertexElementType.Float3, VertexElementSemantic.Position);

      HardwareVertexBuffer buffer =
        HardwareBufferManager.Instance.CreateVertexBuffer(
          decl.GetVertexSize(POSITION),
          vertexData.vertexCount,
          BufferUsage.StaticWriteOnly);

      binding.SetBinding(POSITION, buffer);

      if(includeTextureCoordinates) {
        decl.AddElement(TEXCOORD, 0, VertexElementType.Float2, VertexElementSemantic.TexCoords);

        buffer =
          HardwareBufferManager.Instance.CreateVertexBuffer(
          decl.GetVertexSize(TEXCOORD),
          vertexData.vertexCount,
          BufferUsage.StaticWriteOnly);

        binding.SetBinding(TEXCOORD, buffer);

        buffer.WriteData(0, buffer.Size, texCoords, true);  
      }

      // TODO: Fix
      material = MaterialManager.Instance.GetByName("BaseWhite");
      material.Lighting = false;
    }

    #region SimpleRenderable Members

    public override float BoundingRadius {
      get {
        return 0;
      }
    }

    public override float GetSquaredViewDepth(Camera camera) {
      return 0;
    }

    public override void GetRenderOperation(RenderOperation op) {
      op.vertexData = vertexData;
      op.useIndices = false;
      op.operationType = OperationType.TriangleStrip;
    }

    public override void GetWorldTransforms(Axiom.MathLib.Matrix4[] matrices) {
      // return identity matrix to prevent parent transforms
      matrices[0] = Matrix4.Identity;
    }


    public override bool UseIdentityProjection {
      get {
        return true;
      }
    }

    public override bool UseIdentityView {
      get {
        return true;
      }
    }

    public override Quaternion WorldOrientation {
      get {
        return Quaternion.Identity;
      }
    }

    public override Vector3 WorldPosition {
      get {
        return Vector3.Zero;
      }
    }


    #endregion SimpleRenderable Members

    #region Methods

    /// <summary>
    ///    Sets the corners of the rectangle, in relative coordinates.
    /// </summary>
    /// <param name="left">Left position in screen relative coordinates, -1 = left edge, 1.0 = right edge.</param>
    /// <param name="top">Top position in screen relative coordinates, 1 = top edge, -1 = bottom edge.</param>
    /// <param name="right">Position in screen relative coordinates.</param>
    /// <param name="bottom">Position in screen relative coordinates.</param>
    public void SetCorners(float left, float top, float right, float bottom) {
      float[] data = new float[] {
        left, top, -1,
        left, bottom, -1,
        top, right, -1,
        right, bottom, -1
      };

      HardwareVertexBuffer buffer = 
        vertexData.vertexBufferBinding.GetBuffer(POSITION);

      buffer.WriteData(0, buffer.Size, data, true);

      box = new AxisAlignedBox();
      box.SetExtents(new Vector3(left, top, 0), new Vector3(right, bottom, 0));
    }

    #endregion Methods
  }
}