unify(w3ddisplay): Match Zero Hour texture bit depth in Generals

[Jaredl-Dev]

This fixes the discolored control bar textures in Generals introduced by #726.

Issue

The Generals control bar displays visible discoloration and quantization across its background textures.

Root cause

Before #726, Generals selected texture formats using the device bit depth, keeping the 32-bit control bar textures intact.

#726 made Generals honor WW3D::Get_Texture_Bitdepth(), matching Zero Hour. However, Generals still left the texture bit depth at its default value of 16. This caused the 32-bit control bar textures to be converted from A8R8G8B8 to A4R4G4B4, producing the visible discoloration.

Fix

Generals now sets the texture bit depth to the selected display bit depth after display initialization is complete, restoring the effective pre-#726 rendering behavior. The existing Zero Hour call is moved to the same location to keep both implementations aligned.

Verification

• Built and launched VC6 Release builds immediately before and at [GEN] Bring texture related code in WW3D2 closer to Zero Hour #726 to isolate the regression.
• VC6 Release build succeeds.

[qodo-free-for-open-source-projects]

PR Summary by Qodo

Fix Generals control bar discoloration by forcing 32-bit texture bitdepth

🐞 Bug fix🕐 Less than 10 minutes

AI Description

• Set Generals texture bit depth to 32 during W3DDisplay initialization.
• Prevent 32-bit UI textures from being quantized to 16-bit formats.
• Restore pre-#726 control bar rendering quality while keeping #726 behavior alignment.

Diagram

graph TD
A["Generals client"] --> B["W3DDisplay::init()"] --> C["WW3D render config"] --> D["Set_Texture_Bitdepth(32)"] --> E["Texture format selection"] --> F["Control bar textures"]
subgraph Legend
direction LR
_app["App/Client"] ~~~ _fn["Init function"] ~~~ _cfg["Engine setting"]
end

Loading

High-Level Assessment

The following are alternative approaches to this PR:

1. Set WW3D default texture bit depth to 32 globally

• ➕ Fixes any other callers that forget to set the bit depth
• ➕ Centralizes the default to reduce per-game divergence
• ➖ Riskier: may change behavior for other titles/modes expecting 16-bit default
• ➖ Harder to reason about regressions outside Generals

2. Derive bit depth from device/backbuffer format (pre-#726 style)

• ➕ Adapts automatically to runtime device capabilities
• ➕ Avoids hardcoding and may better match legacy expectations
• ➖ Reintroduces divergence from the post-[GEN] Bring texture related code in WW3D2 closer to Zero Hour #726 model that honors WW3D texture bit depth
• ➖ More complex logic and potentially inconsistent results across devices

3. Expose as Generals config/INI option

• ➕ Enables toggling for compatibility/performance testing without code changes
• ➕ Makes the behavior explicit and documented
• ➖ Adds surface area and support burden for a setting that should be deterministic
• ➖ Still needs a safe default (likely 32)

Recommendation: The PR’s approach (explicitly setting texture bit depth to 32 in Generals’ W3DDisplay initialization) is the best tradeoff: it is minimally invasive, scoped to the affected game, and directly restores the intended 32-bit UI texture path without broad engine-wide side effects.

Files changed (1) +1 / -0

Bug fix (1) +1 / -0

W3DDisplay.cppForce 32-bit texture bit depth during Generals display init+1/-0

Force 32-bit texture bit depth during Generals display init

• Adds an explicit call to set WW3D texture bit depth to 32 as part of W3DDisplay initialization. This prevents 32-bit control bar textures from being converted to lower-precision 16-bit formats, eliminating visible quantization/discoloration introduced by the prior behavioral change.

Generals/Code/GameEngineDevice/Source/W3DDevice/GameClient/W3DDisplay.cpp

[qodo-free-for-open-source-projects]

Code Review by Qodo

🐞 Bugs (1)📘 Rule violations (0)📜 Skill insights (0)

1. Undocumented magic bitdepth 🐞 Bug⚙ Maintainability

Description

W3DDisplay::init hard-codes WW3D::Set_Texture_Bitdepth(32) without documenting that this is
required to prevent 32-bit UI textures being down-converted when the engine default texture depth is
16. This makes the line easy to “clean up” later and accidentally reintroduce the discoloration
regression.

Code

Generals/Code/GameEngineDevice/Source/W3DDevice/GameClient/W3DDisplay.cpp[779]

+ WW3D::Set_Texture_Bitdepth(32);

Evidence

The engine’s default texture bit depth is 16, and the texture format selection logic forces 16-bit
formats whenever Get_Texture_Bitdepth()==16 (even if the device is running at 32-bit). Without an
explanatory comment, the new hard-coded 32 looks arbitrary despite being required to avoid forced
16-bit conversion.

Generals/Code/GameEngineDevice/Source/W3DDevice/GameClient/W3DDisplay.cpp[771-782]
Core/Libraries/Source/WWVegas/WW3D2/dx8wrapper.cpp[90-120]
Core/Libraries/Source/WWVegas/WW3D2/ww3dformat.cpp[339-352]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution
### Issue description
`WW3D::Set_Texture_Bitdepth(32)` is a critical behavioral override but is currently a bare magic number with no in-code explanation. Because WW3D defaults texture depth to 16, removing/altering this line can silently reintroduce 32-bit texture quantization/discoloration.
### Issue Context
- DX8Wrapper default texture depth is 16.
- The format selection path treats `Get_Texture_Bitdepth()==16` as a forced 16-bit pipeline even on 32-bit displays.
### Fix Focus Areas
- Generals/Code/GameEngineDevice/Source/W3DDevice/GameClient/W3DDisplay.cpp[771-782]
- Core/Libraries/Source/WWVegas/WW3D2/dx8wrapper.cpp[90-120]
- Core/Libraries/Source/WWVegas/WW3D2/ww3dformat.cpp[339-352]
### Suggested fix
Add a short comment next to the call explaining it prevents down-conversion of 32-bit UI/controlbar textures (engine default is 16), or replace `32` with a named constant local to W3DDisplay initialization (keeping it explicitly 32, not tied to display bit depth).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

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[stephanmeesters]

Suggest rename PR to:

unify(w3ddisplay): Match Zero Hour texture bit depth in Generals

Fix appears to be wider than just the control bar.

[xezon]

This change somehow cannot be merged. The Merge button is greyed out.

[Jaredl-Dev]

@xezon I believe you can't merge this because the GeneralsMD CI gates appear to be stuck and won't run. I already force-pushed an amended commit with no changes, but they still got stuck.

[xezon]

GeneralsMD is not build because this change only touches Generals. Yet it is marked Required but should not be. This change cannot be merged.

[Jaredl-Dev]

GeneralsMD is not build because this change only touches Generals. Yet it is marked Required but should not be. This change cannot be merged.

Am I supposed to just close this PR and leave this bug in the game? Or are you saying that someone with the proper permissions should address the CI guard?

[stephanmeesters]

Should be possible to merge it with the command line instructions

git checkout -b Jaredl-Dev-fix/generals-controlbar-texture-discoloration main
git pull https://github.com/Jaredl-Dev/GeneralsGameCode.git fix/generals-controlbar-texture-discoloration
git checkout main
git merge --no-ff Jaredl-Dev-fix/generals-controlbar-texture-discoloration
git push origin main

[xezon]

I wonder if there is a bug in our build actions. But I have not seen this problem before. Perhaps try to create a duplicate of this change.

[Mauller]

Looks good

[Mauller]

Maybe gate the fix with #if RTS_GENERALS and add it to both games W3DDisplay.cpp files so it's there for when they are unified.

That should help also get around the CI issue.

Or was this just missing from generals only?

[xezon]

It was copied from ZH.

[Jaredl-Dev]

I have implemented Mauller's suggestion from Discord.

[bobtista]

I see a green "Squash and merge" button, LGTM