#region LGPL License
/*
Axiom Game Engine Library
Copyright (C) 2003 Axiom Project Team
The overall design, and a majority of the core engine and rendering code
contained within this library is a derivative of the open source Object Oriented
Graphics Engine OGRE, which can be found at http://ogre.sourceforge.net.
Many thanks to the OGRE team for maintaining such a high quality project.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#endregion
using System;
using System.Runtime.InteropServices;
using Axiom.Core;
using Axiom.Graphics;
using Tao.OpenGl;
namespace Axiom.RenderSystems.OpenGL{
/// <summary>
/// Summary description for GLHardwareIndexBuffer.
/// </summary>
public class GLHardwareIndexBuffer : HardwareIndexBuffer {
#region Fields
/// <summary>
/// Saves the GL buffer ID for this buffer.
/// </summary>
private int bufferID;
#endregion
#region Constructors
/// <summary>
/// Constructor.
/// </summary>
/// <param name="type">Index type (16 or 32 bit).</param>
/// <param name="numIndices">Number of indices in the buffer.</param>
/// <param name="usage">Usage flags.</param>
/// <param name="useShadowBuffer">Should this buffer be backed by a software shadow buffer?</param>
public GLHardwareIndexBuffer(IndexType type, int numIndices, BufferUsage usage, bool useShadowBuffer)
: base(type, numIndices, usage, false, useShadowBuffer) {
// generate the buffer
Gl.glGenBuffersARB(1, out bufferID);
if(bufferID == 0)
throw new Exception("Cannot create GL index buffer");
Gl.glBindBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, bufferID);
// initialize this buffer. we dont have data yet tho
Gl.glBufferDataARB(
Gl.GL_ELEMENT_ARRAY_BUFFER_ARB,
sizeInBytes,
IntPtr.Zero,
GLHelper.ConvertEnum(usage));
}
#endregion
#region HardwareIndexBuffer Implementation
/// <summary>
///
/// </summary>
/// <param name="offset"></param>
/// <param name="length"></param>
/// <param name="locking"></param>
/// <returns></returns>
protected override IntPtr LockImpl(int offset, int length, BufferLocking locking) {
int access = 0;
if(isLocked) {
throw new Exception("Invalid attempt to lock an index buffer that has already been locked.");
}
// bind this buffer
Gl.glBindBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, bufferID);
if(locking == BufferLocking.Discard) {
// commented out to fix ATI issues
/*Gl.glBufferDataARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB,
sizeInBytes,
IntPtr.Zero,
GLHelper.ConvertEnum(usage));
*/
// find out how we shall access this buffer
access = (usage == BufferUsage.Dynamic) ?
Gl.GL_READ_WRITE_ARB : Gl.GL_WRITE_ONLY_ARB;
}
else if(locking == BufferLocking.ReadOnly) {
if(usage == BufferUsage.WriteOnly) {
LogManager.Instance.Write("Invalid attempt to lock a write-only vertex buffer as read-only.");
}
access = Gl.GL_READ_ONLY_ARB;
}
else if (locking == BufferLocking.Normal || locking == BufferLocking.NoOverwrite) {
access = (usage == BufferUsage.Dynamic) ?
Gl.GL_READ_WRITE_ARB : Gl.GL_WRITE_ONLY_ARB;
}
IntPtr ptr = Gl.glMapBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, access);
if(ptr == IntPtr.Zero) {
throw new Exception("GL Vertex Buffer: Out of memory");
}
isLocked = true;
return new IntPtr(ptr.ToInt32() + offset);
}
/// <summary>
///
/// </summary>
public override void UnlockImpl() {
Gl.glBindBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, bufferID);
if(Gl.glUnmapBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB) == 0) {
throw new Exception("Buffer data corrupted!");
}
isLocked = false;
}
/// <summary>
///
/// </summary>
/// <param name="offset"></param>
/// <param name="length"></param>
/// <param name="src"></param>
/// <param name="discardWholeBuffer"></param>
public override void WriteData(int offset, int length, IntPtr src, bool discardWholeBuffer) {
Gl.glBindBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, bufferID);
if(useShadowBuffer) {
// lock the buffer for reading
IntPtr dest = shadowBuffer.Lock(offset, length,
discardWholeBuffer ? BufferLocking.Discard : BufferLocking.Normal);
// copy that data in there
Memory.Copy(src, dest, length);
// unlock the buffer
shadowBuffer.Unlock();
}
if(discardWholeBuffer) {
Gl.glBufferDataARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB,
sizeInBytes,
IntPtr.Zero,
GLHelper.ConvertEnum(usage));
}
Gl.glBufferSubDataARB(
Gl.GL_ELEMENT_ARRAY_BUFFER_ARB,
offset,
length,
src);
}
/// <summary>
///
/// </summary>
/// <param name="offset"></param>
/// <param name="length"></param>
/// <param name="dest"></param>
public override void ReadData(int offset, int length, IntPtr dest) {
if(useShadowBuffer) {
// lock the buffer for reading
IntPtr src = shadowBuffer.Lock(offset, length, BufferLocking.ReadOnly);
// copy that data in there
Memory.Copy(src, dest, length);
// unlock the buffer
shadowBuffer.Unlock();
}
else {
Gl.glBindBufferARB(Gl.GL_ELEMENT_ARRAY_BUFFER_ARB, bufferID);
Gl.glGetBufferSubDataARB(
Gl.GL_ELEMENT_ARRAY_BUFFER_ARB,
offset,
length,
dest);
}
}
/// <summary>
/// Called to destroy this buffer.
/// </summary>
public override void Dispose() {
Gl.glDeleteBuffersARB(1, ref bufferID);
}
#endregion HardwareIndexBuffer Implementation
#region Properties
/// <summary>
/// Gets the GL buffer ID for this buffer.
/// </summary>
public int GLBufferID {
get {
return bufferID;
}
}
#endregion
}
}
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