Frame Scope and Debugging

Frame functions manage the active MGFX draw frame, rectangular clipping, queued command flush, and debug overlay. Coordinates are relative to the active frame.

Facade aliases: MGFX.StartPanel, MGFX.EndPanel, MGFX.StartScreen, MGFX.EndScreen, MGFX.PushClip, MGFX.PopClip, MGFX.DebugOverlay.

Scope

• Use startPanel / endPanel inside PANEL:Paint.
• Use startScreen / endScreen inside HUDPaint or screen-space overlays.
• pushClip / popClip are rectangular scissor clips, not arbitrary shape masks.

This Page

• startPanel - Start a panel-local MGFX frame and install panel clipping.
• endPanel - End the panel frame, replay queued commands, and clear frame state.
• startScreen - Start a screen-space frame, usually for HUDPaint.
• endScreen - End the screen-space frame and flush queued commands.
• pushClip - Push a frame-local rectangular scissor clip.
• popClip - Pop the current rectangular clip and restore the previous scissor.
• debugOverlay - Draw a small internal render statistics overlay.

Function Reference

startPanel

mgfx.api.startPanel(panel, w, h)

Starts a panel-local MGFX frame and immediately installs panel clipping.

Parameters

Parameter	Description
panel	VGUI panel. panel:LocalToScreen(0, 0) becomes the frame origin.
w, h	Optional frame size. If omitted, MGFX reads panel:GetSize().

Notes

• Call at the beginning of PANEL:Paint or another panel-local paint function.
• Later draw coordinates are panel-local, not screen coordinates.
• Always pair it with endPanel in the same paint pass.

Example

client fn paint(panel, w, h) {
  mgfx.api.startPanel(panel, w, h)
  mgfx.api.roundedBox(0, 0, w, h, 8, Color(20, 24, 32, 230))
  mgfx.api.endPanel()
}

endPanel

mgfx.api.endPanel()

Ends the current panel frame, replays queued text/clip commands, and clears frame state.

Notes

• Shapes and images normally draw immediately; text flushes here.
• Call after all MGFX panel drawing for the current frame.

Example

mgfx.api.startPanel(panel, w, h)
mgfx.api.text("Ready", "DermaDefault", 12, 12, color_white)
mgfx.api.endPanel()

startScreen

mgfx.api.startScreen(w = ScrW(), h = ScrH())

Starts a screen-space MGFX frame, usually for HUDPaint.

Parameters

Parameter	Description
w, h	Optional screen frame size. Defaults to ScrW() and ScrH().

Notes

• Coordinates are already screen-space with the origin at the top left.
• Use for HUD layers, not panel paint.

Example

hook.Add("HUDPaint", "MyHud", () => {
  mgfx.api.startScreen()
  mgfx.api.ring(ScrW() - 72, 72, 28, 5, Color(80, 210, 170))
  mgfx.api.endScreen()
})

endScreen

mgfx.api.endScreen()

Ends the current screen frame and flushes queued commands.

Notes

• Pair with startScreen.
• If text appears behind shapes, issue the text calls later before endScreen.

pushClip

mgfx.api.pushClip(x, y, w, h)

Pushes a rectangular scissor clip relative to the active frame.

Parameters

Parameter	Description
x, y	Clip origin in active frame-local pixels.
w, h	Clip size. Non-positive size becomes an empty clip.

Notes

• This is rectangular clipping only, not a shape mask stack.
• Nested clips intersect with parent clips.

popClip

mgfx.api.popClip()

Pops the current rectangular clip and restores the previous scissor rectangle.

Notes

• Every pushClip should be matched by one popClip.
• An unbalanced clip stack can affect later draws in the same frame.

debugOverlay

mgfx.api.debugOverlay(x = 8, y = 8)

Draws a small internal render statistics overlay.

Parameters

Parameter	Description
x, y	Optional overlay position.

Notes

• Useful during development for draw count, fallback count, and text stats.
• It uses ordinary GMod text and is not intended as production UI.

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