MarcelineVQ
2aaa089c76
Module control API: - Three cdecl exports: WeirdUtils_IsModuleActive, WeirdUtils_DisableModule, WeirdUtils_DisableAll - C header include/weirdutils_api.h for runtime DLL discovery - All modules gain pub module_name, isActive(), shared mutex via src/mutex.zig - build.zig refactored to module_list array of ModuleDesc Bigcursor: - D3D9 vtable hooks on SetCursorProperties/ShowCursor - Scale2x/Scale3x pixel-art upscalers in pure Zig (replaces 12K-line hqx C) - Bilinear resampler for fractional scales (1.0-4.0, default 1.2) - Win32 cursor via CreateIconIndirect bypasses D3D9 32x32 limit - FNV-1a hash cache for ~16 cursor bitmaps - Lua API: SetCursorScale(n) / GetCursorScale() - CVar cursorScale for Config.wtf persistence (tenths) Other: - Add dpslog module stub - Docs and README updates
65 lines
4.1 KiB
Markdown
65 lines
4.1 KiB
Markdown
# JFA Outline Banding Investigation
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## Date: 2026-02-25
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## Problem
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Outlines rendered via the JFA pipeline have a "marching ants" pattern of missing outline pixels. The artifact depends on **which side of the camera** the target is on (screen-space position), not the left/right side of the model itself. Camera-angle dependent.
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## What Was Ruled Out
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### 1. Silhouette RT is clean (CONFIRMED)
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Added `DEBUG_SHOW_SILHOUETTE` comptime flag in `d3d9_hook.zig` that skips JFA and composites the raw silhouette RT directly to the backbuffer. The silhouette was solid with no banding - the cached draw replay produces correct geometry. **Stale VB hypothesis is NOT the cause.**
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### 2. JFA sentinel value (1.0, 1.0) → (-1.0, -1.0) (NO IMPROVEMENT)
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Changed the JFA init shader sentinel from `(1.0, 1.0)` to `(-1.0, -1.0)` so unflooded pixels can't act as false seeds near the right screen edge. This did NOT fix the marching ants pattern. The sentinel is currently set to `(-1.0, -1.0)` in the code (uncommitted).
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### 3. JFA pass count changes pattern but doesn't fix it
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- `[2, 1]` → vertical bands of missing outline
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- `[8, 4, 2, 1]` → marching ants alternating pattern (current uncommitted state)
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### 4. Mid-DIP silhouette drawing corrupts render state (ABANDONED)
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Attempted drawing silhouettes directly in DIP hook. Corrupts WoW's GxDevice state. Reverted.
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### 5. Game object occlusion (FIXED, committed as 661e156)
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Batch reorder puts outline targets last so depth buffer has full scene geometry when stencil marks are written.
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## Current Uncommitted Changes in d3d9_hook.zig
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- JFA steps changed from `[2, 1]` to `[8, 4, 2, 1]`
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- JFA sentinel changed from `(1.0, 1.0)` to `(-1.0, -1.0)`
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- `DEBUG_SHOW_SILHOUETTE` comptime flag added (currently `false`), with `debug_sil_ps` shader
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- Debug shader had a cmp operand inversion bug that was fixed (`c0.w, c0.x` not `c0.x, c0.w`)
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## Remaining Investigation - JFA Pipeline Bug
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Since the silhouette is clean, the bug is in the JFA shaders (Phase 2). Possible causes:
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### A. JFA propagation shader distance comparison logic
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The propagation shader uses `cmp` (ps_3_0) which tests `>= 0` vs `< 0`. When `new_dist² == best_dist²` (exactly equal), `cmp` picks the OLD seed (`>= 0` branch). This tie-breaking might cause systematic bias where seeds from certain directions are always preferred, creating directional artifacts. Worth testing: swap `cmp` operands to prefer new seed on ties, or add a small epsilon.
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### B. dp2add precision on DXVK
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`dp2add r2.z, r2, r2, c1.x` computes `r2.x*r2.x + r2.y*r2.y + 0.0`. DXVK translates this to Vulkan - there may be precision differences vs native D3D9 that affect distance comparisons, especially for pixels equidistant from multiple seeds.
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### C. Neighbor sampling at texture edges
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When `mad r4.xy, offset, step_uv, v0.xy` goes outside [0,1], CLAMP addressing returns the edge texel. This could feed stale/wrong seed UVs into the comparison. Clamping the sample coordinate to valid range before comparison could help.
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### D. The JFA algorithm itself may not suit this use case
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Consider alternative approaches:
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- **Screen-space dilation** (iterative morphological expand of silhouette) - simpler, no distance field needed
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- **Gaussian blur difference** - blur silhouette, subtract original, threshold
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- **Sobel/edge detection** on the silhouette RT
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- Docs in `/media/storage/projects/zig/weirdutils/docs/` describe these alternatives
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- Reference articles: ameye.dev "5 ways to draw an outline", Ben Golus "Quest for Very Wide Outlines"
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## Key Files
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- `src/outline/d3d9_hook.zig` - D3D9 hooks, JFA pipeline, all shaders
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- `src/outline/model_hook.zig` - batch reordering, rendering_outline flag
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- `src/outline/tracker.zig` - per-frame model tracking
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- `src/outline/types.zig` - D3D9 constants
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- `reference/c_overlay/d3d9_hook.cpp` - C reference (uses 3-pass shell extrusion, not JFA)
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## Build / Environment
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- `zig build` from `/media/storage/projects/zig/weirdutils/`
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- Zig 0.15, target x86-windows-msvc (32-bit DLL injected into WoW 3.3.5)
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- Linux host (Arch, kernel 6.16.1), game via Wine/DXVK
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- Git last commit: `661e156` (game object occlusion fix)
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