korender

Kotlin Multiplatform 3D graphics rendering engine based on OpenGL / OpenGL ES / WebGL.

Korender uses declarative approach that seamlessly integrates 3D viewport into Compose Multiplatform UI. Same Korender code runs on all supported platforms.

@Composable
fun App() = Korender(appResourceLoader = { Res.readBytes(it) }) {
  camera = camera(Vec3(0f, 5f, 30f), -1.z, 1.y)
  Frame {
    Pass {
      DirectionalLight(Vec3(1f, -1f, -1f))
      Sky(fastCloudSky())
      Renderable(
        standart {
          baseColor = Green
          pbr.metallic = 0.3f
          pbr.roughness = 0.5f
        },
        mesh = sphere(2f),
        transform = translate(-0.5f.y)
      )
    }
    Pass {
      Screen(water(), fastCloudSky())
      Billboard(fire { yscale = 10f; xscale = 2f }, position = 6.y, transparent = true)
      Gui {
        Filler()
        Text(text = "FPS ${frameInfo.avgFps}", height = 50, color = Red, fontResource = "font/orbitron.ttf", id = "fps")
      }
    }
  }
}

Live web demo: https://zakgof.github.io/projects/korender/wasm/

Korender is BETA - APIs may change without notice.

Supported platforms

Platform	3D API
Desktop (Windows/Linux)	OpenGL 3.3
Android	OpenGL ES 3
Web	WebGL 2

Examples showcase app

• Web live demo https://zakgof.github.io/projects/korender/wasm/
• JVM Desktop Windows: https://github.com/zakgof/korender/releases/download/0.3.0/korender-demo-0.3.0.zip
• Android APK: https://github.com/zakgof/korender/releases/download/0.3.0/korender-demo-0.3.0.apk

Examples source code

Features

• Physically Based Rendering (PBR) metallic-roughness model
• Rendering opaque and transparent objects
• Directional and point lights
• Projection shadow maps with percentage close soft shadows
• Texturing with normal mapping support
• Predefined and custom meshes
• Wavefront .obj and .gtlf/.glb file loading
• Billboards (sprites)
• Batching (instancing)
• Simple heightfield (terrain)
• Textured or shader sky
• On-screen basic GUI
• Custom shaders support
• Multi-pass rendering and screen-space shaders (filters)
• Simple effects
  • smoke
  • fire
  • water

Quick start

• Check out QuickStart application available at https://github.com/zakgof/korender/tree/main/quickstart

or, create an application from scratch:

• Generate a new KMP application using Kotlin Multiplatform Wizard. Select Android and Desktop platforms.
• Add Korender dependency com.github.zakgof:korender:0.3.0
• Add the above code to commonMain
• Run on desktop: .\gradlew composeApp:run

Further reading

Explore the Korender Wiki