This is an improved implementation of "Fast Indirect Illumination Using Two Virtual Spherical Gaussian Lights" on Microsoft MiniEngine. It roughly approximates virtual point lights (VPLs) with two virtual spherical Gaussian lights (VSGLs) for real-time single-bounce indirect illumination.

• Approximate diffuse-to-diffuse, diffuse-to-glossy, glossy-to-diffuse, and glossy-to-glossy reflections
• Completely dynamic, no precomputation and no lookup tables
• Specialized for scenes locally lit by a spotlight

1. Generate VPLs by rendering a reflective shadow map
2. Approximate the VPLs into a diffuse VSGL and glossy VSGL
3. Compute lighting from the two VSGLs

• Light leaks
• No indirect shadows
• Lack of illumination details due to the rough approximation

• Windows 10 version 2004
• Visual Studio 2019 with Windows 10 SDK version 2004

1. Open ModelViewer/ModelViewer.sln
2. Select configuration: Debug (full validation), Profile (instrumented), Release
3. Build and run

• Forward/Backward/Strafe: left thumbstick or WASD (FPS controls)
• Up/Down: triggers or E/Q
• Yaw/Pitch: right thumbstick or mouse

• Forward/Backward/Strafe: left thumbstick or WASD (FPS controls) + left mouse button
• Up/Down: triggers or E/Q + left mouse button
• Yaw/Pitch: right thumbstick or mouse + left mouse button

• Toggle slow movement: click left thumbstick or lshift
• Open debug menu: back button or backspace
• Navigate debug menu: dpad or arrow keys
• Toggle debug menu item: A button or return
• Adjust debug menu value: dpad left/right or left/right arrow keys

This software is released under the MIT License, see LICENSE.txt.