Firmament

Performance release: more frames, the same look.

Performance

• Nether and End: the unused sun shadow map is no longer rendered at all.
• Overworld shadows: a depth-only shadow pass; water and clear glass no longer reach the shadow rasterizer.
• Cloud shadows: read from a small map computed once per frame instead of several noise octaves per lit pixel. Sunlit surface lighting costs less than half as much as in 0.1.1.
• Fog and light shafts: cheaper shadow lookups along each ray (about 1.2×).
• Sky: clouds and stars are rendered after the terrain. Stars are drawn only where the sky is visible; in caves and sealed rooms, clouds hidden by terrain cost much less (about 2.4× for a cave view with a strip of sky).
• Ambient occlusion: open, unoccluded areas skip the reconstruction filter.
• The figures are isolated GPU pass timings measured against 0.1.1 on an RTX 4060 Laptop GPU at 2560 × 1440 with the High preset, not frame rates. In-game FPS depends on the scene, render distance and hardware.

Compatibility

• The same 29 Minecraft Java versions as 0.1.1: 1.18.2; 1.19, 1.19.1, 1.19.2 and 1.19.4; 1.20–1.20.6; 1.21–1.21.11; 26.1, 26.1.1, 26.1.2, 26.2 and 26.3.
• Use the Iris and Sodium builds matching your Minecraft version; 26.2 and 26.3 target the OpenGL renderer. Recorded gameplay evidence remains 1.21.1 / NeoForge 21.1.228 / Iris 1.8.12 / Sodium 0.6.13 with 0.1.0-alpha.2.

Known issues

• After reloading chunks with F3+A, shadows of blocks outside your view appear once you look at them: Iris only builds chunks the camera sees.

Notes

• Rendering, presets and options are unchanged from 0.1.1; automated OpenGL comparisons match it within the project's equivalence limits.
• Keep the ZIP intact, place it in shaderpacks, select Firmament in Iris, start with High and adjust the preset for your setup.