feat: SDF per-pixel ground blend + expanded biomes on a 2x world #221

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panda wants to merge 1 commit from feat/world-new-biomes into main

pull from: feat/world-new-biomes

merge into: marco:main

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marco:feat/biome-props

marco:feat/world-terrain

Conversation 2 Commits 1 Files changed 125 +8327 -1599

panda commented 2026-07-29 19:30:39 +02:00

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Summary

The old dual-grid tile transitions between biomes looked bad — checkerboarding, dark seams and stair-stepped borders where two biomes met. I wanted the biomes to melt into each other instead of showing tile edges.

This PR replaces the discrete dual-grid ground with a per-pixel Signed-Distance-Field blend running in a shader, expands the biome set from the cleaned E:\Asset art, and doubles the world to 768×576 so the biomes and the titanic redwood forest have room to breathe.

Rendering — SDF ground blend (client/IsoMmo.Client.Core/TerrainBlendField.cs, GroundBlendRenderer.cs, Content/ground_blend.fx):

• Per-biome signed distance fields (exact EDT) → smoothstep weights; 12 slots (three RGBA texture sets) so busy junctions never drop a biome.
• Global graph-colouring of the biome co-occurrence graph → each biome uses one slot map-wide, so bilinear weight interpolation stays valid across chunk borders (kills the chunk seams / bright streaks).
• Wrap-guttered biome atlas (no tile-boundary bleed), low-frequency domain-warp on the tiling (breaks the per-cell grid), linear-space mixing.
• A light Gaussian blur on the SDFs rounds boundary corners, so there are no sharp dark spikes where a jagged biome pokes into a lighter one.

Content:

• New biomes from E:\Asset: the four redwood floor types (mossy / bark / humus / mixed), dirt + snow roads (snow only over arctic ground), typed beaches; scripts/genland.py turns the raw art into the repo's seamless tile format.
• World doubled to 768×576; the coastal volcano now sits on solid land (was half-submerged); redwood giants scattered with a minimum spacing so their crowns don't overlap into a wall.

Fix:

• Static flicker: the cull margin now accounts for tall/wide sprites, so a titanic redwood's canopy stays drawn when its foot scrolls off-screen.

Screenshots / recording

Captured by piloting the client via the debug harness (login test, /tp <x> <y> through chat, screenshot):

Before — dual-grid tiles	After — per-pixel SDF blend (2× world)

Redwood forest — the titanic giants spread with gaps and clearings (not an overlapping wall):

A biome boundary that used to show a hard dark spike — now rounded:

The coastal volcano, now on solid, walkable land:

How it was tested

• New unit tests against the pure field logic: TerrainBlendFieldTests + EdtTests (interior purity, border blend, ∑weights = 1, cross-chunk slot consistency, overflow, determinism). Client.Core 130 green.
• dotnet test IsoMmo.slnx — whole solution green.
• Whole solution builds with 0 warnings; dotnet csharpier check . clean.
• Drove the client to a classic beach, the multi-biome coast, the redwood forest, the volcano and the worst 8-biome junction; screenshotted each (attached).

Checklist

• just lint passes (CSharpier + analyzers, zero warnings)
• just test is green
• The whole solution builds (client and tools included)
• Multi-platform preserved (MonoGame DesktopGL + .NET; the shader is ps_3_0/GLSL via MGCB — no OS-specific deps)
• Tests added/updated for this change
• Linked the related issue — no single issue; the transition system was designed and iterated live

Notes / follow-ups (before merge)

• docs/architecture.md still to document the SDF ground blend.
• The old DrawDualTile path is kept behind a flag (GroundBlend != null) as a fallback; can be removed.
• scripts/genscatter.py (redwood/arena prop re-scatter) still lives in a scratchpad; should move into scripts/ and be decoupled from the git-HEAD baseline.
• The 768² field + blur adds a few seconds to client startup — candidate for optimisation.

## Summary The old dual-grid tile transitions between biomes looked bad — checkerboarding, dark seams and stair-stepped borders where two biomes met. I wanted the biomes to melt into each other instead of showing tile edges. This PR replaces the discrete dual-grid ground with a **per-pixel Signed-Distance-Field blend** running in a shader, expands the biome set from the cleaned `E:\Asset` art, and **doubles the world to 768×576** so the biomes and the titanic redwood forest have room to breathe. **Rendering — SDF ground blend** (`client/IsoMmo.Client.Core/TerrainBlendField.cs`, `GroundBlendRenderer.cs`, `Content/ground_blend.fx`): - Per-biome signed distance fields (exact EDT) → smoothstep weights; **12 slots** (three RGBA texture sets) so busy junctions never drop a biome. - **Global graph-colouring** of the biome co-occurrence graph → each biome uses one slot map-wide, so bilinear weight interpolation stays valid across chunk borders (kills the chunk seams / bright streaks). - Wrap-guttered biome atlas (no tile-boundary bleed), low-frequency **domain-warp** on the tiling (breaks the per-cell grid), **linear-space** mixing. - A light Gaussian blur on the SDFs rounds boundary **corners**, so there are no sharp dark spikes where a jagged biome pokes into a lighter one. **Content**: - New biomes from `E:\Asset`: the four redwood floor types (mossy / bark / humus / mixed), dirt + snow roads (snow only over arctic ground), typed beaches; `scripts/genland.py` turns the raw art into the repo's seamless tile format. - World doubled to **768×576**; the coastal volcano now sits on **solid land** (was half-submerged); redwood giants scattered with a **minimum spacing** so their crowns don't overlap into a wall. **Fix**: - Static **flicker**: the cull margin now accounts for tall/wide sprites, so a titanic redwood's canopy stays drawn when its foot scrolls off-screen. ## Screenshots / recording Captured by piloting the client via the debug harness (`login test`, `/tp <x> <y>` through chat, `screenshot`): | Before — dual-grid tiles | After — per-pixel SDF blend (2× world) | |---|---| |  |  | **Redwood forest** — the titanic giants spread with gaps and clearings (not an overlapping wall):  **A biome boundary that used to show a hard dark spike — now rounded:**  **The coastal volcano, now on solid, walkable land:**  ## How it was tested - New unit tests against the pure field logic: `TerrainBlendFieldTests` + `EdtTests` (interior purity, border blend, ∑weights = 1, cross-chunk slot consistency, overflow, determinism). **Client.Core 130 green.** - `dotnet test IsoMmo.slnx` — whole solution green. - Whole solution builds with **0 warnings**; `dotnet csharpier check .` clean. - Drove the client to a classic beach, the multi-biome coast, the redwood forest, the volcano and the worst 8-biome junction; screenshotted each (attached). ## Checklist - [x] `just lint` passes (CSharpier + analyzers, zero warnings) - [x] `just test` is green - [x] The whole solution builds (client and tools included) - [x] Multi-platform preserved (MonoGame DesktopGL + .NET; the shader is `ps_3_0`/GLSL via MGCB — no OS-specific deps) - [x] Tests added/updated for this change - [ ] Linked the related issue — no single issue; the transition system was designed and iterated live ## Notes / follow-ups (before merge) - `docs/architecture.md` still to document the SDF ground blend. - The old `DrawDualTile` path is kept behind a flag (`GroundBlend != null`) as a fallback; can be removed. - `scripts/genscatter.py` (redwood/arena prop re-scatter) still lives in a scratchpad; should move into `scripts/` and be decoupled from the git-HEAD baseline. - The 768² field + blur adds a few seconds to client startup — candidate for optimisation.

redwood_forest.png

2.9 MiB

before_dualgrid.png

2.3 MiB

volcano_on_land.png

2.7 MiB

after_sdf_coast.png

2.7 MiB

boundary_rounded.png

2.5 MiB

panda added 3 commits 2026-07-29 19:30:39 +02:00

feat(assets): import authored biome props as statics, scattered per biome (#137) a801f97077

feat(content): 66 authored biome props, forests, and a 256x192 biome world (#137) 89d2478c23

feat: SDF per-pixel ground blend + expanded biomes on a 2x world 1756a3d68b

panda force-pushed feat/world-new-biomes from 1756a3d68b to 2c77adac19 2026-07-29 19:43:44 +02:00 Compare

panda force-pushed feat/world-new-biomes from 2c77adac19 to e402f7ac6a 2026-07-29 20:02:13 +02:00 Compare

panda referenced this pull request 2026-07-29 20:25:47 +02:00

feat(client): animated terrain fluids (ocean/lava/rivers) on the SDF blend #222

panda commented 2026-08-02 00:23:30 +02:00

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Chiudo, superata, Shag succhiami il cazzo

Chiudo, superata, Shag succhiami il cazzo

panda closed this pull request 2026-08-02 00:23:30 +02:00

panda commented 2026-08-02 01:06:08 +02:00

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Superseded. The SDF per-pixel ground blend is already on main (via the later blend/fluids path), and main now carries 29 terrain biomes vs the 21 on this branch — main is ahead, nothing unique left to salvage. Closing rather than rebasing 125 files / +8.3k lines of overlap.

Superseded. The SDF per-pixel ground blend is already on `main` (via the later blend/fluids path), and `main` now carries **29** terrain biomes vs the **21** on this branch — main is ahead, nothing unique left to salvage. Closing rather than rebasing 125 files / +8.3k lines of overlap.

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