BlitzMax 135 Up!

Rem
bbdoc: Grab an image from the back buffer with Virtual support
about:
Copies pixels from the back buffer to an image frame.

Only images created with the DYNAMICIMAGE flag can be grabbed.
End Rem
Function VirtualGrabImage(image:TImage, X:Int, Y:Int, Frame:Int = 0)

	Local gcr:Int, gcg:Int, gcb:Int
	GetMaskColor(gcr, gcg, gcb)
	
	Local gcw:Float = VirtualResolutionWidth() / GraphicsWidth()
	Local gch:Float = VirtualResolutionHeight() / GraphicsHeight()
	Local pixmap:TPixmap = _max2dDriver.GrabPixmap(X / gcw, Y / gch, image.width / gcw, image.Height / gch)
	
	If image.flags&MASKEDIMAGE 
		pixmap = MaskPixmap(pixmap, gcr, gcg, gcb)
	EndIf
	
	image.SetPixmap(Frame, pixmap)
	
End Function

Rem
bbdoc: Set Virtual drawing viewport
about:
The current ViewPort defines an area within the back buffer that all drawing is clipped to. Any
regions of a DrawCommand that fall outside the current Virtual ViewPort are not drawn.
End Rem
Function SetVirtualViewport(X:Int, Y:Int, Width:Int, Height:Int)
	
	Local gcw:Float = VirtualResolutionWidth() / GraphicsWidth()
	Local gch:Float = VirtualResolutionHeight() / GraphicsHeight()
	
	X:/gcw
	Y:/gch
	Width:/gcw
	Height:/gch
	
	SetViewport(X, Y, Width, Height)
	
End Function

Rem
bbdoc: Get Virtual dimensions of current Viewport.
returns: The horizontal, vertical, width and height values of the current Virtual Viewport in the variables supplied.
End Rem
Function GetVirtualViewport(X:Int Var, Y:Int Var, Width:Int Var, Height:Int Var)

	Local gcw:Float = VirtualResolutionWidth() / GraphicsWidth()
	Local gch:Float = VirtualResolutionHeight() / GraphicsHeight()

	GetViewport(X, Y, Width, Height)

	X:*gcw
	Y:*gch
	Width:*gcw
	Height:*gch
	
End Function

SetGraphicsDriver GLMax2DDriver()

Graphics(640, 480)
SetVirtualResolution(1024.0, 768.0)

Local CW:Float = 250.0
Local CH:Float = 141.0

SetBlend(LIGHTBLEND)
SetAlpha(0.75)

While Not KeyHit(KEY_ESCAPE)
	
	' Press SPACE to cycle various virtual resolution
	If KeyHit(KEY_SPACE)
		Select VirtualResolutionWidth()
			Case 1280.0
				SetVirtualResolution(640.0, 480.0)
			Case 1024.0
				SetVirtualResolution(1280.0, 1024.0)
			Case 640.0
				SetVirtualResolution(800.0, 600.0)
			Case 800.0
				SetVirtualResolution(1024.0, 768.0)
		End Select
	End If
	
	If KeyHit(KEY_ENTER)
		If CW = 250.0
			CW = 320.0
			CH = 240.0
		Else
			CW = 250.0
			CH = 141.0
		End If
	EndIf
	
	Cls()

	SetColor(128, 128, 255)
	drawCamera(VirtualMouseX(), VirtualMouseY(), CW, CH)
	
	'Draw the viewport in the middle of the screen
	SetColor(128, 255, 128)
	drawCamera((VirtualResolutionWidth() - CW) / 2.0, (VirtualResolutionHeight() - CH) / 2.0, CW, CH)
	
	'Draw the viewport at 0,0
	SetColor(255, 128, 128)
	drawCamera(0.0, 0.0, CW, CH)

	SetColor(255, 255, 255)
	drawCamera(0.0, 0.0, VirtualResolutionWidth(), VirtualResolutionHeight())

	SetScale(VirtualResolutionWidth() / GraphicsWidth(), VirtualResolutionHeight() / GraphicsHeight ())
	DrawText("Press SPACE to cycle virtual resolution and ENTER to change camera size", 10.0, 10.0)
	DrawText("Virtual Resolution:" + Int(VirtualResolutionWidth()) + "x" + Int(VirtualResolutionHeight()), 10.0, 32.0)
	SetScale(1.0, 1.0)
	
	Flip()
	
Wend


Rem
bbdoc: Simply draw a viewport Camera with border line
End Rem
Function drawCamera(camX:Float, camY:Float, camWidth:Float, camHeight:Float)

	SetVirtualViewport(camX, camY, camWidth, camHeight)
	
	' Reset View Port Origin for Layer Rendering
	SetOrigin (camX, camY)

	DrawLine(0.0, 0.0, camWidth - 1.0, 0.0)
	DrawLine(0.0, 0.0, 0.0, camHeight - 1.0)
	DrawLine(0.0, camHeight - 1.0, camWidth - 1.0, camHeight - 1.0)
	DrawLine(camWidth - 1.0, 0.0, camWidth - 1.0, camHeight - 1.0)

End Function


Rem
bbdoc: Set Virtual drawing viewport
about:
The current ViewPort defines an area within the back buffer that all drawing is clipped to. Any
regions of a DrawCommand that fall outside the current Virtual ViewPort are not drawn.
End Rem
Function SetVirtualViewport(X:Int, Y:Int, Width:Int, Height:Int)
	
	Local gcw:Float = VirtualResolutionWidth() / GraphicsWidth()
	Local gch:Float = VirtualResolutionHeight() / GraphicsHeight()
	
	X:/gcw
	Y:/gch
	Width:/gcw
	Height:/gch
	
	SetViewport(X, Y, Width, Height)
	
End Function

Function SetVirtualViewport(X:Int, Y:Int, W:Int, H:Int)
	Local xx:Float = GraphicsWidth()/VirtualResolutionWidth()
	Local yy:Float = GraphicsHeight()/VirtualResolutionHeight()
	x=Floor(xx*x)
	y=Floor(yy*y)
	w=Floor(xx*w)
	h=Floor(yy*h)
	SetOrigin x/xx,y/yy	
	SetViewport x,y,w+2,h+2
End Function