A configurable sunrise over a curved planetary horizon, built with Compose Multiplatform.

Android · Desktop/JVM · iOS · Explore presets · Run the demo · Effect reference

Horizon Bloom combines atmospheric light, a glowing sun, aurora, stars, clouds, and subtle lens effects in a single Compose scene. Drag to shift the view; tap to trigger an aurora glow. Every effect can be adjusted independently.

Latest release: v0.1.1 · Core on Maven Central · Demo on Maven Central.

Dawn → Twilight → Aurora → custom · Watch in full resolution

Dawn	Twilight	Aurora

Every preview above was captured from the actual Compose renderer. These are showcase variants derived from presets, not untouched preset defaults. They vary sun placement, size, horizon height, and light while keeping planet curvature consistent.

The 0.1.1 release is published under the shared Maven group io.github.velord.horizonbloom. Add the renderer (core) to your Kotlin Multiplatform module's build.gradle.kts:

commonMain.dependencies {
    implementation("io.github.velord.horizonbloom:core:0.1.1")
}

Render it anywhere inside a Compose UI:

import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.ui.Modifier
import com.velord.horizonbloom.HorizonBloom
import com.velord.horizonbloom.HorizonBloomConfig

HorizonBloom(
    config = HorizonBloomConfig.DAWN,
    modifier = Modifier.fillMaxSize(),
)

Expand a preset to see a ready-to-use configuration. For a live, adjustable scene, use the demo application.

HorizonBloom(config = HorizonBloomConfig.DAWN)

HorizonBloom(config = HorizonBloomConfig.TWILIGHT)

HorizonBloom(config = HorizonBloomConfig.AURORA)

All presets are ordinary HorizonBloomConfig values. Use copy() to fine-tune them:

val config = HorizonBloomConfig.AURORA.copy(
    flare = 0.4f,
    stars = 1.0f,
    speed = 0.7f,
    interactive = true,
)

HorizonBloom(config = config)

import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.velord.horizonbloom.HorizonBloom
import com.velord.horizonbloom.HorizonBloomConfig

@Composable
fun HorizonSample() {
    val configState = remember { mutableStateOf(HorizonBloomConfig.DAWN) }

    Column {
        Row {
            TextButton(onClick = { configState.value = HorizonBloomConfig.DAWN }) {
                Text("Dawn")
            }
            TextButton(onClick = { configState.value = HorizonBloomConfig.TWILIGHT }) {
                Text("Twilight")
            }
            TextButton(onClick = { configState.value = HorizonBloomConfig.AURORA }) {
                Text("Aurora")
            }
        }

        HorizonBloom(
            config = configState.value,
            modifier = Modifier.fillMaxWidth().height(280.dp),
        )
    }
}

Sun position, size, horizon, atmosphere, spread, bloom, sunburst and flare adjusted live · Watch the full video

The custom scene derives from Twilight with a shifted sun and tuned light:

The included demo lets you switch presets, edit colors, adjust effect strengths, pause animation, and test pointer interaction. The interactive editor is an optional, published Compose Multiplatform artifact. Add it to commonMain:

commonMain.dependencies {
    implementation("io.github.velord.horizonbloom:demo:0.1.1")
}

Call HorizonDemoApp(onBackClick) from your Compose navigation host. The demo resolves the matching core artifact transitively; you do not need to declare both unless you also consume core directly. Version 0.1.0 contains only the original renderer under the legacy Maven coordinates.

Building from source requires JDK 21; Android also needs an Android SDK, and iOS requires macOS with Xcode.

Set interactive = false to disable tap and drag input. See the effect reference for how each control affects the renderer.

Supported targets: Android (API 26+), Desktop/JVM, iOS ARM64 devices, and Apple Silicon iOS simulators.

Apache License 2.0. Source and demo are in this repository. The :horizon-bloom and :demo modules are published on Maven Central. See the publishing guide for the release process.