axiosengine/axios/PrimitiveBatch.cs

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2012-03-19 23:57:59 +00:00
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
namespace FarseerPhysics.DebugViews
{
public class PrimitiveBatch : IDisposable
{
private const int DefaultBufferSize = 500;
// a basic effect, which contains the shaders that we will use to draw our
// primitives.
private BasicEffect _basicEffect;
// the device that we will issue draw calls to.
private GraphicsDevice _device;
// hasBegun is flipped to true once Begin is called, and is used to make
// sure users don't call End before Begin is called.
private bool _hasBegun;
private bool _isDisposed;
private VertexPositionColor[] _lineVertices;
private int _lineVertsCount;
private VertexPositionColor[] _triangleVertices;
private int _triangleVertsCount;
/// <summary>
/// the constructor creates a new PrimitiveBatch and sets up all of the internals
/// that PrimitiveBatch will need.
/// </summary>
/// <param name="graphicsDevice">The graphics device.</param>
public PrimitiveBatch(GraphicsDevice graphicsDevice)
: this(graphicsDevice, DefaultBufferSize)
{
}
public PrimitiveBatch(GraphicsDevice graphicsDevice, int bufferSize)
{
if (graphicsDevice == null)
{
throw new ArgumentNullException("graphicsDevice");
}
_device = graphicsDevice;
_triangleVertices = new VertexPositionColor[bufferSize - bufferSize % 3];
_lineVertices = new VertexPositionColor[bufferSize - bufferSize % 2];
// set up a new basic effect, and enable vertex colors.
_basicEffect = new BasicEffect(graphicsDevice);
_basicEffect.VertexColorEnabled = true;
}
#region IDisposable Members
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
#endregion
public void SetProjection(ref Matrix projection)
{
_basicEffect.Projection = projection;
}
protected virtual void Dispose(bool disposing)
{
if (disposing && !_isDisposed)
{
if (_basicEffect != null)
_basicEffect.Dispose();
_isDisposed = true;
}
}
/// <summary>
/// Begin is called to tell the PrimitiveBatch what kind of primitives will be
/// drawn, and to prepare the graphics card to render those primitives.
/// </summary>
/// <param name="projection">The projection.</param>
/// <param name="view">The view.</param>
public void Begin(ref Matrix projection, ref Matrix view)
{
if (_hasBegun)
{
throw new InvalidOperationException("End must be called before Begin can be called again.");
}
//tell our basic effect to begin.
_basicEffect.Projection = projection;
_basicEffect.View = view;
_basicEffect.CurrentTechnique.Passes[0].Apply();
// flip the error checking boolean. It's now ok to call AddVertex, Flush,
// and End.
_hasBegun = true;
}
public bool IsReady()
{
return _hasBegun;
}
public void AddVertex(Vector2 vertex, Color color, PrimitiveType primitiveType)
{
if (!_hasBegun)
{
throw new InvalidOperationException("Begin must be called before AddVertex can be called.");
}
if (primitiveType == PrimitiveType.LineStrip ||
primitiveType == PrimitiveType.TriangleStrip)
{
throw new NotSupportedException("The specified primitiveType is not supported by PrimitiveBatch.");
}
if (primitiveType == PrimitiveType.TriangleList)
{
if (_triangleVertsCount >= _triangleVertices.Length)
{
FlushTriangles();
}
_triangleVertices[_triangleVertsCount].Position = new Vector3(vertex, -0.1f);
_triangleVertices[_triangleVertsCount].Color = color;
_triangleVertsCount++;
}
if (primitiveType == PrimitiveType.LineList)
{
if (_lineVertsCount >= _lineVertices.Length)
{
FlushLines();
}
_lineVertices[_lineVertsCount].Position = new Vector3(vertex, 0f);
_lineVertices[_lineVertsCount].Color = color;
_lineVertsCount++;
}
}
/// <summary>
/// End is called once all the primitives have been drawn using AddVertex.
/// it will call Flush to actually submit the draw call to the graphics card, and
/// then tell the basic effect to end.
/// </summary>
public void End()
{
if (!_hasBegun)
{
throw new InvalidOperationException("Begin must be called before End can be called.");
}
// Draw whatever the user wanted us to draw
FlushTriangles();
FlushLines();
_hasBegun = false;
}
private void FlushTriangles()
{
if (!_hasBegun)
{
throw new InvalidOperationException("Begin must be called before Flush can be called.");
}
if (_triangleVertsCount >= 3)
{
int primitiveCount = _triangleVertsCount / 3;
// submit the draw call to the graphics card
_device.SamplerStates[0] = SamplerState.AnisotropicClamp;
_device.DrawUserPrimitives(PrimitiveType.TriangleList, _triangleVertices, 0, primitiveCount);
_triangleVertsCount -= primitiveCount * 3;
}
}
private void FlushLines()
{
if (!_hasBegun)
{
throw new InvalidOperationException("Begin must be called before Flush can be called.");
}
if (_lineVertsCount >= 2)
{
int primitiveCount = _lineVertsCount / 2;
// submit the draw call to the graphics card
_device.SamplerStates[0] = SamplerState.AnisotropicClamp;
_device.DrawUserPrimitives(PrimitiveType.LineList, _lineVertices, 0, primitiveCount);
_lineVertsCount -= primitiveCount * 2;
}
}
}
}