http://kiyavashkandar.com/clustered-forward-lighting
- C++ OpenGL lighting technique using GPU computing.
- Suitable for large numbers of lights in a scene.
- Crytek Sponza scene is used to demonstrate.
WARNING: ASSIMP LOAD TIMES FOR SPONZA TAKE ~35 SECONDS
Requires OpenGL 4.5 or above.
- Splits screen into a 3 dimensional grid.
- Assigns a light to a tile if the light's sphere intersects with it.
- Fragment shader in lighting pass calculates which tile it belongs to and applies all lights that collide with it to the fragment colour.
Uses an additional culling stage.
- One screen space sized cube is used.
- Any lights that do not collide with it are not considered for the algorithm above.
- Real time shadows + soft shadows.
- Screen space ambient occlusion.
- Bloom.
- Motion blur
- PBR (on PBR branch)
- Transparency
See Game/run.cpp
See Game/GLConfig
Global settings can be modified in GLConfig.h and GLConfig.cpp. Any changes that are made to the grid and lights here are then written to Shaders/Compute/configuration.glsl on start-up (before shaders are compiled). This is included/added in the required compute shaders and lighting pass.
GLConfig:
//...
static const int NUM_X_AXIS_TILES = 10;
static const int NUM_Y_AXIS_TILES = 10;
static const int NUM_Z_AXIS_TILES = 10;
static constexpr int NUM_TILES = NUM_X_AXIS_TILES * NUM_Y_AXIS_TILES * NUM_Z_AXIS_TILES;
static const int NUM_LIGHTS = 100;
//...configuration.glsl
const int numTiles = 1000;
const int numLights = 100;
const vec3 tilesOnAxes = vec3(10, 10, 10);Some preset scenes and configurations are provided to assist with performance analysis including:
- A more visually appealing scene.
- 100 lights.
- 512 lights.
- 1024 lights.
- 2048 lights.
To choose a preset, uncomment the macro in GLConfig.h
#define DEMO_PRETTY
//#define DEMO_100_LIGHTS
//#define DEMO_512_LIGHTS
//#define DEMO_1024_LIGHTS
//#define DEMO_2048_LIGHTS- WASD = Move.
- C = Move down.
- Space = Move up.
- R = Recompile and link shaders.
- P = Display profiler.
- O (when profiler enabled) = Display light positions.
- J = Move lights every frame.
- T = Enabled tiled view. This displays the number of lights intersecting with each tile.