Procedural space skyboxes for Built-in, URP and HDRP. Paint nebulae, stars and your own NASA photos into HDR cubemaps, then render them with a 3-layer parallax skybox shader.tool generate a cubemap dds texture witch may use in any RPBuild deep-space skyboxes inside Unity, in seconds, without ever leaving the editor.WEBGL DemoCosmic SkyBox Generator is a procedural cubemap authoring tool and a parallax space shader in one package. You stack nebula layers, star layers and image layers in a dedicated editor window, watch a live 256 px preview update as you drag sliders, then bake the result to an HDR cubemap and render it through a skybox shader that ships for Built-in, URP and HDRP.DROP IN ANY IMAGE YOU LIKEEvery sky can carry your own textures. Take a public-domain NASA plate, a Hubble galaxy, a painted nebula, a planet render, a logo — assign it to a Textured Layer, set its angular size and position on the sphere, pick a blend mode, and it is projected straight into the cubemap alongside the procedural content. Black is treated as fully transparent, so cut-outs need no alpha work. Layers can be drawn before the nebulae, before the stars, or on top of everything.PARALLAX THAT ACTUALLY MOVESThe included parallax skybox shader samples three separate cubemaps — deep space, far stars, near stars — and shifts each one by its own amount as the camera turns. The result is a sky with real depth: distant nebulae sit still while foreground star fields drift across them. No script, no companion component, no per-frame setup. The effect is driven entirely from the view matrix, so it works in the editor, in play mode, and in builds identically.ONE CLICK, THREE LAYERSAssign each layer a parallax group — Background, Middle or Foreground — and the generator splits the bake automatically. Four cubemaps are written and dropped straight into the right material slots. You keep authoring one sky; the tool sorts out the depth separation for you.ALL THREE PIPELINESBuilt-in, URP and HDRP each get their own shader variant exposing identical parameters. The HDRP version registers as a native sky type through the volume framework, complete with a custom sky renderer, correct sun injection and seam-free reflection baking. Each shader declares its package requirement, so uninstalled pipelines are skipped instead of throwing import errors.BUILT FOR ITERATIONSettings save and load as JSON presets. The generator runs cube-face rasterisation on Parallel.For. Auto Update Preview re-bakes a fast 256 px sky half a second after your last slider move, so tuning a nebula feels immediate. When you like it, hit Generate and get the full-resolution cubemap.Output is a proper RGBAHalf DDS cubemap with a DX10 header, so nothing is clipped, HDR bloom has real values to work with, and the file imports cleanly into Unity 6.Full source included. C# and HLSL, readable, no DLLs.Procedural nebulae — Perlin, Fractal, Ridged and FBM noise, HDR gradient mapping, spiral twirl with adjustable arm count, contrast, threshold, octaves, lacunarity, persistenceProcedural star fields — count, HDR colour, size range, soft halo, and 8-point diffraction raysTextured layers — project any image onto the sky sphere; angular size, spherical position, blend mode and draw stage per layer; black reads as transparentUnlimited layers of every type, freely reordered6 blend modes — Normal, Screen, Clamp, Replace, Multiply, Lerp3-layer parallax skybox shader with independent parallax strength and HDR tint per layerAutomatic split bake — tag layers Background / Middle / Foreground and get three cubemaps wired into the material in one clickBuilt-in, URP and HDRP shader variants with identical parametersNative HDRP sky type via volume override, with sun injection and parallax disabled during reflection bakes to avoid seamsAnimated star twinkle with speed, intensity, density and cell-size controlSun disc with soft edge, HDR corona and a rotating ray texture of your choiceMotion blur and auto rotation for warp and drift effectsPer-channel colour grading, contrast, brightness and exposure directly on the sky materialLive 256 px preview with optional auto-update on every parameter changeJSON presets — save, load and share entire skiesRGBAHalf DDS cubemap export with DX10 header, any face resolutionMultithreaded generation via Parallel.ForDemo camera controller (orbit and free flight, mouse, keyboard and touch) and a runtime skybox switcherFull C# and HLSL source, no third-party dependencies
