Home▸Game Development▸Field of View (2D) — Shadow-Casting Visibility Polygon

👁️ Field of View (2D) — Shadow-Casting Visibility Polygon

Interactive 2D top-down field-of-view simulator. Cast rays across an NPC's vision cone toward every obstacle corner, trim each ray at the nearest wall, and build the exact visibility polygon in real time.

Game Development2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

Details

CategoryGame Development

RenderingCanvas 2D

DifficultyModerate

Target FPS60

ControlsDrag the NPC (cyan dot) to move it, Click empty space in Move mode to face the NPC there, Switch to Add Wall mode and click-drag to draw a rectangular obstacle, Drag an existing wall to reposition it, Clear Walls button removes all obstacles, FOV angle slider sets the vision cone width (10°-360°), View distance slider sets the maximum sight range, NPC turn speed slider controls auto-rotation speed (0 freezes facing)

game-airaycastingvisibility-polygonstealthshadow-castingline-of-sight

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⚙ Under the hood

A top-down 2D field-of-view simulator. It casts rays from an NPC toward every obstacle corner inside its vision cone, stops each ray at the first wall it hits, and connects the ordered hit points into a precise visibility polygon. Adjust the field-of-view angle and view distance, drag the NPC to aim it, and draw or move rectangular walls to watch the polygon update and see when the target enters its sight.

game-airaycastingvisibility-polygonstealthshadow-castingline-of-sight

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install