Project Report

Please read "Dynamic Pixel Perfect Shadows In 2D Scenes.pdf" to learn more about the project.

Usage

The main components of this light and shadow casting example are:

• lights/lightsource.script - Attach this script to any game object that should act as a lightsource. Modify the exposed script properties to control the light properties:
  • radius [number] - Radius of the lightsource in pixels
  • color [vector4] - Color of the lightsource (RGBA)
  • arc_angle [number] - Arc angle of the lightsource. Can be used to generate a cone of light up to an arc angle of 180 degrees. Anything above 180 degrees will result in a full circle.
  • static [boolean] - Use this for static lights that do not move or rotate to skip updates of light position and rotation each frame.
  • falloff [number] - This controls the light intensity. With a falloff of 1.0 the light intensity gradually decreases until there is no light right at the edge. With a falloff of 2 the light intensity decreases twice as fast.
  • enabled [boolean] - Set to false to disable the light.
• lights/render/light_quad.go - A game object with a basic model quad, used as a render target when drawing lights and shadows.
• lights/render/lights.render and lights/render/lights.render_script - The render file and render script used when drawing lights and shadows (and also all of the standard Defold components such as sprites, particles, tilemaps etc)
• lights/materials/light_occluder_*.material - Materials to use for sprite, tilemaps and other components that should occlude light and cast shadows.

Step 1 - Render script

Open game.project and scroll down to Bootstrap and change Render file to lights/render/lights.render. This render script works like the default render script with the addition of also drawing lights and shadows.

Step 2 - Add light quad

Add the lights/render/light_quad.go to a collection where lights and shadows should be calculated.

Step 3 - Add lightsources

Attach the lights/lightsource.script to any game object that should act as a lightsource.

Configure the lightsource properties to your liking.

Step 4 - Add light occluders

Change the material for any component that should cast shadows when lit by a lightsource. Select a material from lights/materials/ matching the component type casting shadows.

Example

There is an example included in this repository. It sets up a few lightsources and occluders and lets you move around the scene.