Implement Two-Level Detail Cloud Modeling

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akadmin/NemesisEngine#24

akadmin commented

2026-01-18 14:22:25 +00:00

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Description:
Implement the cloud sampling technique from Horizon paper using low-frequency base shape and high-frequency detail.
Tasks:

Create cloud sampler function in shader
Sample base shape from 128³ Perlin-Worley texture
Implement height gradient for cloud types (cumulus, stratus, stratocumulus)
Apply coverage parameter to base shape
Erode base shape with 32³ Worley detail texture
Apply detail only at cloud edges
Invert Worley at cloud base for wispy bottoms
Apply 2D curl noise distortion
Add cloud type parameter (blend between height gradients)
Add coverage parameter
Test transitions between cloud types
Verify billowing, cauliflower-like shapes appear

Acceptance Criteria:

Clouds have realistic billowing shapes
Cloud types (cumulus, stratus) visually distinct
Coverage parameter controls cloud amount naturally
Wispy bottoms and rounded tops visible
Detail erosion adds realism without artifacts

Related Issues: Depends on #22, #23
Resources:

Horizon Zero Dawn paper (modeling section)

Estimated Time: 5-6 days

Description: Implement the cloud sampling technique from Horizon paper using low-frequency base shape and high-frequency detail. Tasks: - [x] Create cloud sampler function in shader - [x] Sample base shape from 128³ Perlin-Worley texture - [x] Implement height gradient for cloud types (cumulus, stratus, stratocumulus) - [x] Apply coverage parameter to base shape - [x] Erode base shape with 32³ Worley detail texture - [x] Apply detail only at cloud edges - [x] Invert Worley at cloud base for wispy bottoms - [x] Apply 2D curl noise distortion - [x] Add cloud type parameter (blend between height gradients) - [x] Add coverage parameter - [x] Test transitions between cloud types - [x] Verify billowing, cauliflower-like shapes appear Acceptance Criteria: Clouds have realistic billowing shapes Cloud types (cumulus, stratus) visually distinct Coverage parameter controls cloud amount naturally Wispy bottoms and rounded tops visible Detail erosion adds realism without artifacts Related Issues: Depends on #22, #23 Resources: Horizon Zero Dawn paper (modeling section) Estimated Time: 5-6 days

akadmin added this to the Volumetric Clouds - Part 1 (Basic Ray Marching) milestone

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akadmin added this to the Horizon Zero Dawn Clouds project

akadmin referenced this issue

2026-01-18 14:23:24 +00:00

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akadmin referenced this issue from a commit