phase

Overlay

phase Overlay

Overlay runs after Render and after every engine-owned drawing system (sprites, lights, the scene's shows menu), so a handler … phase Overlay paints on top of the finished world: health bars, score, prompts, a boss bar. With @ClearColor the engine owns the clear and the present, so an Overlay handler only draws — no Screen.clear, no Screen.show. Like Render, it should read the world and never change it.

Example

program OverlayExample {
  property Position { column: int = 0, row: int = 0 }
  model Player { Position }

  const TILE_SIZE: int = 16
  var score: int = 0

  handler PlacePlayer phase Start {
    spawn Player { Position { column: 5, row: 6 } }
  }

  @ClearColor(Color.MidnightBlue)
  handler DrawWorld phase Render {
    for (current_position) in query [Position, {Player}] {
      Screen.fill_rectangle(
        x: current_position.column * TILE_SIZE,
        y: current_position.row * TILE_SIZE,
        width: TILE_SIZE, height: TILE_SIZE, color: Color.LimeGreen)
    }
  }

  handler DrawHud phase Overlay {
    Screen.draw_text(x: 6, y: 4, text: "SCORE", color: Color.White, scale: 1)
    Screen.draw_number(x: 52, y: 4, value: score, color: Color.Gold, scale: 1)
  }
}

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