Fast 2D gradients?

Graphics 640,480,0,0

Repeat

	x:Float = rnd(0,GraphicsWidth())
	y:Float = rnd(0,GraphicsHeight())
	w:Float = rnd(1,GraphicsWidth())
	h:Float = rnd(1,GraphicsHeight())

	r0:Float = rnd(0,255)
	g0:Float = rnd(0,255)
	b0:Float = rnd(0,255)

	r1:Float = rnd(0,255)
	g1:Float = rnd(0,255)
	b1:Float = rnd(0,255)

	direction:Int = Rand(0,1)

	DrawGradient(x,y,w,h,r0,g0,b0,r1,g1,b1,direction)

	Flip

Until KeyHit(KEY_ESCAPE)
End

Function DrawGradient(x:Float,y:Float,w:Float,h:Float,r0:Float=255.0,g0:Float=0.0,b0:Float=0.0,r1:Float=255.0,g1:Float=255.0,b1:Float=0.0,direction:Int=0)

	r0 = r0/255.0
	g0 = g0/255.0
	b0 = b0/255.0
	
	r1 = r1/255.0
	g1 = g1/255.0
	b1 = b1/255.0

	glBegin GL_QUADS
		glColor3f r0,g0,b0
		glVertex2f x,y

		If direction = 0
			glColor3f r0,g0,b0
		Else
			glColor3f r1,g1,b1
		EndIf
		glVertex2f x+w,y

		glColor3f r1,g1,b1
		glVertex2f x+w,y+h

		If direction = 0
			glColor3f r1,g1,b1
		Else
			glColor3f r0,g0,b0
		EndIf
		glVertex2f x,y+h
	glEnd
	
EndFunction