Java implemetation of the approximate ray/beam casting algorithm for a discrete 2D tilemaps.
For a square 2D map that consists of tiles (NxN tiles), where each tile can be either empty, or contain light source or obstacle, this algorithm calculates approximate brightness of each tile, taking into account positions of the light sources and occlusion from the obstacles.
(image was generated with LightingTest)
- JS demo
- More detailed description by Kevin Granade
If the input field is NxN tiles:
- worst case
O(N³)(for the number of light sources between N and N²) - best case is
O(N²)(for constant number of light sources) - CPU cache friednly (all data structures are accessed sequentially)
Naive ray/shadowcasting implementation is O(N⁴) in worst case
(O(N²) for each of O(N²) light sources).
This algorithm is O(N³) worst case (and it really matters when N >= 100).
See benchmarks.
Maven is used for building. Java 17 or newer is a prerequisite.
- Build and run tests:
./mvnw clean install - Run benchmarks after build:
java -jar target/benchmarks.jar - For specific benchmarks:
java -jar target/benchmarks.jar [benchmark class name](e.g.,java -jar target/benchmarks.jar LightingBenchmark)
- Lighting.java Class that implements the lighting calculation
- LightingBenchmark.java JMH benchmark for lighting
- Rotation.java Utility class for matrix rotations
- RotationBenchmark.java Rotations benchmark
- LightingTest.java Simple unit test for lighting. Additionally generates PNG with the results.
Copyright © 2018 Ivan Zaitsev (https://github.com/Aivean/efficient-2d-raycasting)
