From dbf0218371ce006b674b0ede8e6a4d97932ff2c6 Mon Sep 17 00:00:00 2001
From: Leonardo Bishop <me@leonardobishop.com>
Date: Tue, 1 Aug 2023 01:31:25 +0100
Subject: Add footprints

---
 code/entity/Footprint.cs | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 code/entity/Footprint.cs

(limited to 'code/entity')

diff --git a/code/entity/Footprint.cs b/code/entity/Footprint.cs
new file mode 100644
index 0000000..8941e95
--- /dev/null
+++ b/code/entity/Footprint.cs
@@ -0,0 +1,55 @@
+using System;
+
+namespace MurderGame;
+
+using Sandbox;
+// It's just a square with a material slapped onto it.
+public class Footprint : RenderEntity
+{
+	public Material SpriteMaterial { get; set; }
+
+	public float SpriteScale { get; set; } = 18f;
+
+	public bool Enabled { get; set; } = true;
+	
+	public Color Color { get; set; }
+
+	private TimeSince TimeSinceCreated = 0;
+	
+	[GameEvent.Tick.Client]
+	public void OnTick()
+	{
+		if ( !(TimeSinceCreated > Math.Clamp(MurderGame.MaxFootprintTime, 0, 30)) )
+		{
+			return;
+		}
+
+		Enabled = false;
+		Delete();
+	}
+	
+	public override void DoRender(SceneObject obj)
+	{
+		if (!Enabled) return;
+
+		// Allow lights to affect the sprite
+		Graphics.SetupLighting(obj);
+		// Create the vertex buffer for the sprite
+		var vb = new VertexBuffer();
+		vb.Init(true);
+
+		// Vertex buffers are in local space, so we need the camera position in local space too
+		var normal = new Vector3( 0, 0.01f, 100 );
+		var w = normal.Cross(Vector3.Down).Normal;
+		var h = normal.Cross(w).Normal;
+		float halfSpriteSize = SpriteScale / 2;
+
+		// Add a single quad to our vertex buffer
+		vb.AddQuad(new Ray(default, normal), halfSpriteSize*w, h*halfSpriteSize);
+		
+		Graphics.Attributes.Set( "color",  Color);
+		
+		// Draw the sprite
+		vb.Draw( SpriteMaterial );
+	}
+}
-- 
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