Bloom

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Bloom adds a glow around the parts of an HDR texture brighter than a threshold. It is rendered after the scene and before the Tonemapper.

Bloom

Creates a Bloom for the HDR texture format. More mipLevels give a wider glow.

val bloom = Bloom(device, TextureFormat.RGBA16_FLOAT, mipLevels = 6)
bloom.threshold = 1f
bloom.softKnee = 0.5f
bloom.intensity = 0.3f
bloom.radius = 1f

Rendering

Render bloom on the HDR texture after the scene pass ends and then tonemap it. The HDR texture needs the RENDER_ATTACHMENT and TEXTURE usages and must not be multisampled.

onUpdate { dt ->
    renderFrame { frame, commandEncoder ->
        val scenePass = ... // HDR render pass
        modelBatch.render(model, camera, environment)
        modelBatch.flush(scenePass, camera, dt)
        scenePass.end()

        bloom.render(commandEncoder, hdrTarget.view, hdrTarget.width, hdrTarget.height)

        val surfacePass = ... // surface render pass
        tonemapper.render(surfacePass, hdrTarget.view)
        surfacePass.end()
    }
}

onRelease {
    bloom.release()
}

Emissive Materials

An emissive PBRMaterial glows once its emissiveFactor goes over the threshold.

val material =
    PBRMaterial(
        device,
        baseColorTexture = Textures.textureWhite,
        emissiveFactor = Vec3f(4f, 1f, 0.5f),
    )

HDR

Bloom needs colors brighter than 1.0, so it requires HDR and Tonemapping.

val hdrFormat = TextureFormat.RGBA16_FLOAT
val modelBatch =
    ModelBatch(device).apply {
        addPipelineProvider(PBRMaterialPipelineProvider())
        colorFormat = hdrFormat
    }
val bloom = Bloom(device, hdrFormat)
val tonemapper = Tonemapper(device, graphics.preferredFormat)

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