Image buffer for BlitzMax

timagebuffer.bmx

Type TImageBuffer
	Field rb:Int[1]
	Field fb:Byte[1]
	Field origX:Int, OrigY:Int
	Field origW:Int, OrigH:Int
	Field width:Int, height:Int
	Field glTextureId:Int

	Method Create:TImageBuffer( image:TImage, frameNo:Int = 0 )
		_initBuffer( image.width, image.height, TGLImageFrame( Image.frame( frameNo ) ).name )
		Return Self
	EndMethod

	Method _initBuffer( width:Int, height:Int, glTextureId:Int )
		Self.width = width
		Self.height = height
		Self.glTextureId = glTextureId
		
		_generateFBO()
	EndMethod
	
	Method _generateFBO()
		Local w:Int = width
		Local h:Int = height
		
		AdjustTexSize( W , H )
		
		glGenFramebuffersEXT( 1, fb )
		glGenRenderbuffersEXT( 1 , rb )
		
		glBindTexture( GL_TEXTURE_2D, glTextureId )
		glBindFramebufferEXT( GL_FRAMEBUFFER_EXT , fb[0] )
		
		glFramebufferTexture2DEXT( GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D,  glTextureId, 0 )
		glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, rb[0] )
		glRenderbufferStorageEXT( GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, W, H )
		glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT , GL_DEPTH_ATTACHMENT_EXT , GL_RENDERBUFFER_EXT , rb[0] )
		
		Local status:Int =  glCheckFramebufferStatusEXT( GL_FRAMEBUFFER_EXT )
		
		Select status
			Case GL_FRAMEBUFFER_COMPLETE_EXT
				Print( "OK" + " : " + Status )
			Case GL_FRAMEBUFFER_UNSUPPORTED_EXT
				Print( "GL Framebuffer Unsupported - choose different formats" )
			Default
				End
		EndSelect
	EndMethod

	Method Bind()
		GetViewport( OrigX, OrigY, OrigW, OrigH )
		glBindFramebufferEXT( GL_FRAMEBUFFER_EXT , fb[0] )
		glMatrixMode( GL_PROJECTION )
		glLoadIdentity()
		glOrtho( 0, width, 0, width, -1, 1 )
		glMatrixMode( GL_MODELVIEW )
		glViewport( 0, 0, width, height )
		glScissor( 0, 0, width, height )
	EndMethod

	Method Unbind()
		glBindFramebufferEXT( GL_FRAMEBUFFER_EXT , 0 )
		glMatrixMode( GL_PROJECTION )
		glLoadIdentity()
		glOrtho( 0, OrigW, Origh, 0, -1, 1 )
		glMatrixMode( GL_MODELVIEW )
		glViewport( 0, 0, OrigW, OrigH )
		glScissor( 0, 0, OrigW, OrigH )
	EndMethod
EndType