refactor(baseheightmap): Extract scorch rendering from BaseHeightMap into new W3DScorch

[stephanmeesters]

• Extracts the scorch rendering code into its own class W3DScorch
• Usages of the macro DO_SCORCH have mostly been removed
• Disabling DO_SCORCH before didn't compile but this has been fixed. Scorches are now disabled using W3DScorchDummy when using DO_SCORCH=0
• W3DScorchDummy could be used in headless mode (not part of this PR)

N.B. some code was in DO_SCORCH that didn't actually belong inside the macro, for example Real m_curImpassableSlope;

[greptile-apps]

Greptile Summary

This PR extracts terrain-scorch ownership and rendering from BaseHeightMap into W3DScorch.

• Adds W3DScorch and its no-op W3DScorchDummy implementation.
• Delegates scorch allocation, invalidation, storage, and drawing from BaseHeightMap.
• Updates flat and regular height-map render paths to use the delegated renderer.
• Registers the new source and header in the GameEngineDevice target.

Confidence Score: 4/5

The PR appears safe to merge, with only the previously reported unreachable disabled-scorch branch remaining.

The rendering refactor preserves the active scorch path, while the no-op implementation remains inaccessible because the feature macro is still hardcoded on.

Files Needing Attention: Core/GameEngineDevice/Include/W3DDevice/GameClient/BaseHeightMap.h; Core/GameEngineDevice/Source/W3DDevice/GameClient/BaseHeightMap.cpp

Important Files Changed

Filename	Overview
Core/GameEngineDevice/Source/W3DDevice/GameClient/W3DScorch.cpp	Implements the extracted scorch lifecycle, geometry generation, and draw submission.
Core/GameEngineDevice/Include/W3DDevice/GameClient/W3DScorch.h	Defines the real and no-op scorch-rendering implementations.
Core/GameEngineDevice/Source/W3DDevice/GameClient/BaseHeightMap.cpp	Replaces embedded scorch state and behavior with delegation to the new renderer.
Core/GameEngineDevice/Include/W3DDevice/GameClient/BaseHeightMap.h	Removes embedded scorch data and exposes the delegated draw entry point.
Core/GameEngineDevice/Source/W3DDevice/GameClient/FlatHeightMap.cpp	Routes flat-terrain scorch drawing through BaseHeightMap.
Core/GameEngineDevice/Source/W3DDevice/GameClient/HeightMap.cpp	Routes regular-terrain scorch drawing through BaseHeightMap.
Core/GameEngineDevice/CMakeLists.txt	Adds the extracted scorch implementation to the device-library sources.

Sequence Diagram

sequenceDiagram
    participant Terrain as HeightMap Render
    participant Base as BaseHeightMap
    participant Scorch as W3DScorch
    participant Map as WorldHeightMap
    participant DX8 as DX8Wrapper
    Terrain->>Base: drawScorches()
    Base->>Scorch: drawScorches(map)
    Scorch->>Map: read terrain heights and flip state
    Scorch->>Scorch: rebuild vertex/index buffers when invalidated
    Scorch->>DX8: bind buffers, shader, and texture
    Scorch->>DX8: Draw_Triangles()

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[greptile-apps]

Disabled scorch branch stays enabled

When the build configures DO_SCORCH=0, the unconditional #define DO_SCORCH 1 in BaseHeightMap.h replaces that value before this branch is evaluated, so the real renderer is constructed instead of W3DScorchDummy and the advertised disabled-scorch configuration is ineffective.

Prompt To Fix With AI

This is a comment left during a code review.
Path: Core/GameEngineDevice/Source/W3DDevice/GameClient/BaseHeightMap.cpp
Line: 274-278

Comment:
**Disabled scorch branch stays enabled**

When the build configures `DO_SCORCH=0`, the unconditional `#define DO_SCORCH 1` in `BaseHeightMap.h` replaces that value before this branch is evaluated, so the real renderer is constructed instead of `W3DScorchDummy` and the advertised disabled-scorch configuration is ineffective.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

[stephanmeesters]

I think that's fine for now, DO_SCORCH is not defined in the cmake

[greptile-apps]

Fair enough. That said, #define DO_SCORCH 1 is still unconditionally present in BaseHeightMap.h (line ~72), which means the #else / W3DScorchDummy branch in the constructor is dead code right now — not just unused via CMake, but literally unreachable.

That's not a blocker, but if the intent is to wire up the toggle in the future, the #define DO_SCORCH 1 in the header would need to be removed so the value can come from the build system. You may want to leave a // TODO: comment there or just remove the define now to make the branch live. Either way, happy to drop the original comment if you're treating W3DScorchDummy as forward-looking scaffolding.