Make SMBX's screen smaller

viewport.lua

local viewport = {}

viewport.width, viewport.height = 640,480

local cam = Camera.get()[1]
local buffer = Graphics.CaptureBuffer(cam.width,cam.height)

function viewport.onInitAPI()
	registerEvent(viewport,"onCameraUpdate")
end

function viewport.onCameraUpdate()

	local boundary = player.sectionObj.boundary
	
	local pHeight = player:getCurrentPlayerSetting().hitboxHeight
	
	local midX = player.x + player.width/2
	local midY = player.y + player.height - pHeight/2
	
	local x = {min = midX - viewport.width /2, max = midX + viewport.width /2}
	local y = {min = midY - viewport.height/2, max = midY + viewport.height/2}
	
	if x.min < boundary.left then
		x.max = x.max + (boundary.left - x.min)
		x.min = boundary.left
	elseif x.max > boundary.right then
		x.min = x.min - (x.max - boundary.right)
		x.max = boundary.right
	end
	
	if y.min < boundary.top then
		y.max = y.max + (boundary.top - y.min)
		y.min = boundary.top
	elseif y.max > boundary.bottom then
		y.min = y.min - (y.max - boundary.bottom)
		y.max = boundary.bottom
	end
		
	x.min = (x.min - cam.x)/cam.width
	x.max = (x.max - cam.x)/cam.width
	y.min = (y.min - cam.y)/cam.height
	y.max = (y.max - cam.y)/cam.height
	
	buffer:captureAt(-0.2)
	Graphics.glDraw{
		texture = buffer,
		vertexCoords = {
			0,         0,
			cam.width, 0,
			cam.width, cam.height,
			0,         cam.height
		},
		textureCoords = {
			x.min, y.min,
			x.max, y.min,
			x.max, y.max,
			x.min, y.max
		},
		primitive = Graphics.GL_TRIANGLE_FAN, 
		priority = -0.1
    }
end

return viewport