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#region - - - License - - -
/ * Licensed under the MIT / X11 license .
* Copyright ( c ) 2006 - 2008 the OpenTK Team .
* This notice may not be removed from any source distribution .
* See license . txt for licensing details .
* /
#endregion
using System ;
using System.Diagnostics ;
using System.Drawing ;
using OpenTK ;
using OpenTK.Input ;
using OpenTK.Graphics ;
using OpenTK.Graphics.OpenGL ;
namespace Examples.Tutorial
{
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[Example("Framebuffer Objects", ExampleCategory.OpenGL, "FBO", Documentation="FramebufferObject")]
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public class SimpleFBO : GameWindow
{
public SimpleFBO ( )
: base ( 800 , 600 )
{
}
Font sans = new Font ( System . Drawing . FontFamily . GenericSansSerif , 16.0f ) ;
uint ColorTexture ;
uint DepthTexture ;
uint FBOHandle ;
const int TextureSize = 512 ;
#region Randoms
Random rnd = new Random ( ) ;
public const float scale = 3f ;
/// <summary>Returns a random Float in the range [-0.5*scale..+0.5*scale]</summary>
public float GetRandom ( )
{
return ( float ) ( rnd . NextDouble ( ) - 0.5 ) * scale ;
}
/// <summary>Returns a random Float in the range [0..1]</summary>
public float GetRandom0to1 ( )
{
return ( float ) rnd . NextDouble ( ) ;
}
#endregion Randoms
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protected override void OnLoad ( EventArgs e )
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{
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if ( ! GL . GetString ( StringName . Extensions ) . Contains ( "EXT_framebuffer_object" ) )
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{
System . Windows . Forms . MessageBox . Show (
"Your video card does not support Framebuffer Objects. Please update your drivers." ,
"FBOs not supported" ,
System . Windows . Forms . MessageBoxButtons . OK , System . Windows . Forms . MessageBoxIcon . Exclamation ) ;
Exit ( ) ;
}
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GL . Enable ( EnableCap . DepthTest ) ;
GL . ClearDepth ( 1.0f ) ;
GL . DepthFunc ( DepthFunction . Lequal ) ;
GL . Disable ( EnableCap . CullFace ) ;
GL . PolygonMode ( MaterialFace . Back , PolygonMode . Line ) ;
// Create Color Tex
GL . GenTextures ( 1 , out ColorTexture ) ;
GL . BindTexture ( TextureTarget . Texture2D , ColorTexture ) ;
GL . TexImage2D ( TextureTarget . Texture2D , 0 , PixelInternalFormat . Rgba8 , TextureSize , TextureSize , 0 , PixelFormat . Rgba , PixelType . UnsignedByte , IntPtr . Zero ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureMinFilter , ( int ) TextureMinFilter . Linear ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureMagFilter , ( int ) TextureMagFilter . Linear ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureWrapS , ( int ) TextureWrapMode . ClampToBorder ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureWrapT , ( int ) TextureWrapMode . ClampToBorder ) ;
// GL.Ext.GenerateMipmap( GenerateMipmapTarget.Texture2D );
// Create Depth Tex
GL . GenTextures ( 1 , out DepthTexture ) ;
GL . BindTexture ( TextureTarget . Texture2D , DepthTexture ) ;
GL . TexImage2D ( TextureTarget . Texture2D , 0 , ( PixelInternalFormat ) All . DepthComponent32 , TextureSize , TextureSize , 0 , PixelFormat . DepthComponent , PixelType . UnsignedInt , IntPtr . Zero ) ;
// things go horribly wrong if DepthComponent's Bitcount does not match the main Framebuffer's Depth
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureMinFilter , ( int ) TextureMinFilter . Linear ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureMagFilter , ( int ) TextureMagFilter . Linear ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureWrapS , ( int ) TextureWrapMode . ClampToBorder ) ;
GL . TexParameter ( TextureTarget . Texture2D , TextureParameterName . TextureWrapT , ( int ) TextureWrapMode . ClampToBorder ) ;
// GL.Ext.GenerateMipmap( GenerateMipmapTarget.Texture2D );
// Create a FBO and attach the textures
GL . Ext . GenFramebuffers ( 1 , out FBOHandle ) ;
GL . Ext . BindFramebuffer ( FramebufferTarget . FramebufferExt , FBOHandle ) ;
GL . Ext . FramebufferTexture2D ( FramebufferTarget . FramebufferExt , FramebufferAttachment . ColorAttachment0Ext , TextureTarget . Texture2D , ColorTexture , 0 ) ;
GL . Ext . FramebufferTexture2D ( FramebufferTarget . FramebufferExt , FramebufferAttachment . DepthAttachmentExt , TextureTarget . Texture2D , DepthTexture , 0 ) ;
#region Test for Error
switch ( GL . Ext . CheckFramebufferStatus ( FramebufferTarget . FramebufferExt ) )
{
case FramebufferErrorCode . FramebufferCompleteExt :
{
Console . WriteLine ( "FBO: The framebuffer is complete and valid for rendering." ) ;
break ;
}
case FramebufferErrorCode . FramebufferIncompleteAttachmentExt :
{
Console . WriteLine ( "FBO: One or more attachment points are not framebuffer attachment complete. This could mean there’ s no texture attached or the format isn’ t renderable. For color textures this means the base format must be RGB or RGBA and for depth textures it must be a DEPTH_COMPONENT format. Other causes of this error are that the width or height is zero or the z-offset is out of range in case of render to volume." ) ;
break ;
}
case FramebufferErrorCode . FramebufferIncompleteMissingAttachmentExt :
{
Console . WriteLine ( "FBO: There are no attachments." ) ;
break ;
}
/ * case FramebufferErrorCode . GL_FRAMEBUFFER_INCOMPLETE_DUPLICATE_ATTACHMENT_EXT :
{
Console . WriteLine ( "FBO: An object has been attached to more than one attachment point." ) ;
break ;
} * /
case FramebufferErrorCode . FramebufferIncompleteDimensionsExt :
{
Console . WriteLine ( "FBO: Attachments are of different size. All attachments must have the same width and height." ) ;
break ;
}
case FramebufferErrorCode . FramebufferIncompleteFormatsExt :
{
Console . WriteLine ( "FBO: The color attachments have different format. All color attachments must have the same format." ) ;
break ;
}
case FramebufferErrorCode . FramebufferIncompleteDrawBufferExt :
{
Console . WriteLine ( "FBO: An attachment point referenced by GL.DrawBuffers() doesn’ t have an attachment." ) ;
break ;
}
case FramebufferErrorCode . FramebufferIncompleteReadBufferExt :
{
Console . WriteLine ( "FBO: The attachment point referenced by GL.ReadBuffers() doesn’ t have an attachment." ) ;
break ;
}
case FramebufferErrorCode . FramebufferUnsupportedExt :
{
Console . WriteLine ( "FBO: This particular FBO configuration is not supported by the implementation." ) ;
break ;
}
default :
{
Console . WriteLine ( "FBO: Status unknown. (yes, this is really bad.)" ) ;
break ;
}
}
// using FBO might have changed states, e.g. the FBO might not support stereoscopic views or double buffering
int [ ] queryinfo = new int [ 6 ] ;
GL . GetInteger ( GetPName . MaxColorAttachmentsExt , out queryinfo [ 0 ] ) ;
GL . GetInteger ( GetPName . AuxBuffers , out queryinfo [ 1 ] ) ;
GL . GetInteger ( GetPName . MaxDrawBuffers , out queryinfo [ 2 ] ) ;
GL . GetInteger ( GetPName . Stereo , out queryinfo [ 3 ] ) ;
GL . GetInteger ( GetPName . Samples , out queryinfo [ 4 ] ) ;
GL . GetInteger ( GetPName . Doublebuffer , out queryinfo [ 5 ] ) ;
Console . WriteLine ( "max. ColorBuffers: " + queryinfo [ 0 ] + " max. AuxBuffers: " + queryinfo [ 1 ] + " max. DrawBuffers: " + queryinfo [ 2 ] +
"\nStereo: " + queryinfo [ 3 ] + " Samples: " + queryinfo [ 4 ] + " DoubleBuffer: " + queryinfo [ 5 ] ) ;
Console . WriteLine ( "Last GL Error: " + GL . GetError ( ) ) ;
#endregion Test for Error
GL . PushAttrib ( AttribMask . ViewportBit ) ;
{
GL . Viewport ( 0 , 0 , TextureSize , TextureSize ) ;
// clear the screen in red, to make it very obvious what the clear affected. only the FBO, not the real framebuffer
GL . ClearColor ( 1f , 0f , 0f , 0f ) ;
GL . Clear ( ClearBufferMask . ColorBufferBit | ClearBufferMask . DepthBufferBit ) ;
// smack 50 random triangles into the FBO's textures
GL . Begin ( BeginMode . Triangles ) ;
{
for ( int i = 0 ; i < 50 ; i + + )
{
GL . Color3 ( GetRandom0to1 ( ) , GetRandom0to1 ( ) , GetRandom0to1 ( ) ) ;
GL . Vertex3 ( GetRandom ( ) , GetRandom ( ) , GetRandom ( ) ) ;
GL . Color3 ( GetRandom0to1 ( ) , GetRandom0to1 ( ) , GetRandom0to1 ( ) ) ;
GL . Vertex3 ( GetRandom ( ) , GetRandom ( ) , GetRandom ( ) ) ;
GL . Color3 ( GetRandom0to1 ( ) , GetRandom0to1 ( ) , GetRandom0to1 ( ) ) ;
GL . Vertex3 ( GetRandom ( ) , GetRandom ( ) , GetRandom ( ) ) ;
}
}
GL . End ( ) ;
}
GL . PopAttrib ( ) ;
GL . Ext . BindFramebuffer ( FramebufferTarget . FramebufferExt , 0 ) ; // disable rendering into the FBO
GL . ClearColor ( . 1f , . 2f , . 3f , 0f ) ;
GL . Color3 ( 1f , 1f , 1f ) ;
GL . Enable ( EnableCap . Texture2D ) ; // enable Texture Mapping
GL . BindTexture ( TextureTarget . Texture2D , 0 ) ; // bind default texture
}
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protected override void OnUnload ( EventArgs e )
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{
// Clean up what we allocated before exiting
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if ( ColorTexture ! = 0 )
GL . DeleteTextures ( 1 , ref ColorTexture ) ;
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if ( DepthTexture ! = 0 )
GL . DeleteTextures ( 1 , ref DepthTexture ) ;
if ( FBOHandle ! = 0 )
GL . Ext . DeleteFramebuffers ( 1 , ref FBOHandle ) ;
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}
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protected override void OnResize ( EventArgs e )
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{
GL . Viewport ( 0 , 0 , Width , Height ) ;
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double aspect_ratio = Width / ( double ) Height ;
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OpenTK . Matrix4 perspective = OpenTK . Matrix4 . CreatePerspectiveFieldOfView ( MathHelper . PiOver4 , ( float ) aspect_ratio , 1 , 64 ) ;
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GL . MatrixMode ( MatrixMode . Projection ) ;
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GL . LoadMatrix ( ref perspective ) ;
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Matrix4 lookat = Matrix4 . LookAt ( 0 , 0 , 3 , 0 , 0 , 0 , 0 , 1 , 0 ) ;
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GL . MatrixMode ( MatrixMode . Modelview ) ;
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GL . LoadMatrix ( ref lookat ) ;
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base . OnResize ( e ) ;
}
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protected override void OnUpdateFrame ( FrameEventArgs e )
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{
base . OnUpdateFrame ( e ) ;
if ( Keyboard [ Key . Escape ] )
this . Exit ( ) ;
}
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protected override void OnRenderFrame ( FrameEventArgs e )
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{
GL . Clear ( ClearBufferMask . ColorBufferBit | ClearBufferMask . DepthBufferBit ) ;
GL . PushMatrix ( ) ;
{
// Draw the Color Texture
GL . Translate ( - 1.1f , 0f , 0f ) ;
GL . BindTexture ( TextureTarget . Texture2D , ColorTexture ) ;
GL . Begin ( BeginMode . Quads ) ;
{
GL . TexCoord2 ( 0f , 1f ) ;
GL . Vertex2 ( - 1.0f , 1.0f ) ;
GL . TexCoord2 ( 0.0f , 0.0f ) ;
GL . Vertex2 ( - 1.0f , - 1.0f ) ;
GL . TexCoord2 ( 1.0f , 0.0f ) ;
GL . Vertex2 ( 1.0f , - 1.0f ) ;
GL . TexCoord2 ( 1.0f , 1.0f ) ;
GL . Vertex2 ( 1.0f , 1.0f ) ;
}
GL . End ( ) ;
// Draw the Depth Texture
GL . Translate ( + 2.2f , 0f , 0f ) ;
GL . BindTexture ( TextureTarget . Texture2D , DepthTexture ) ;
GL . Begin ( BeginMode . Quads ) ;
{
GL . TexCoord2 ( 0f , 1f ) ;
GL . Vertex2 ( - 1.0f , 1.0f ) ;
GL . TexCoord2 ( 0.0f , 0.0f ) ;
GL . Vertex2 ( - 1.0f , - 1.0f ) ;
GL . TexCoord2 ( 1.0f , 0.0f ) ;
GL . Vertex2 ( 1.0f , - 1.0f ) ;
GL . TexCoord2 ( 1.0f , 1.0f ) ;
GL . Vertex2 ( 1.0f , 1.0f ) ;
}
GL . End ( ) ;
}
GL . PopMatrix ( ) ;
this . SwapBuffers ( ) ;
}
#region public static void Main ( )
/// <summary>
/// Entry point of this example.
/// </summary>
[STAThread]
public static void Main ( )
{
using ( SimpleFBO example = new SimpleFBO ( ) )
{
Utilities . SetWindowTitle ( example ) ;
example . Run ( 30.0 , 0.0 ) ;
}
}
#endregion
}
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}