[Bug 60490] New: d3dx9: D3DXCheckVersion rejects D3D_SDK_VERSION with the D3D_DEBUG_INFO bit (Dungeon Defenders 2 crashes at startup)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60490

            Bug ID: 60490
           Summary: d3dx9: D3DXCheckVersion rejects D3D_SDK_VERSION with
                    the D3D_DEBUG_INFO bit (Dungeon Defenders 2 crashes at
                    startup)
           Product: Wine
           Version: 11.18
          Hardware: x86-64
                OS: MacOS
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: d3d-util
          Assignee: [e-mail]
          Reporter: [e-mail]
  Target Milestone: ---

**Wine version:** 11.18 (Gcenx macOS build); `dlls/d3dx9_36/main.c` unchanged
on master as of 2026-10-10
**OS:** macOS 27.0.1, Apple Silicon (Rosetta 2); the code path is
platform-independent

**Summary**

Programs compiled with `D3D_DEBUG_INFO` defined get `D3D_SDK_VERSION` as `(32 |
0x80000000)`
from d3d9.h, and pass that to both `Direct3DCreate9` and `D3DXCheckVersion`.
Wine's
`Direct3DCreate9` accepts it, but `D3DXCheckVersion` only returns TRUE for
exactly 32:

```c
BOOL WINAPI D3DXCheckVersion(UINT d3d_sdk_ver, UINT d3dx_sdk_ver)
{
    return d3d_sdk_ver == D3D_SDK_VERSION && d3dx_sdk_ver == D3DX_SDK_VERSION;
}
```

Dungeon Defenders 2 (Unreal Engine 3, Steam app 236110; both its Win32 and
Win64 exes) calls
`D3DXCheckVersion(0x80000020, 43)` from d3dx9_43 right after creating its D3D9
object, and on
FALSE writes to address 3 (Unreal's assert crash), every launch, on any D3D
backend. The game
runs on Windows, so native d3dx9_43 accepts the value.

**Disassembly at the crash (Win64 build)**

```
140c22c8e:  movl  $0x2b, %edx            ; D3DX_SDK_VERSION 43
140c22c93:  movl  $0x80000020, %ecx      ; D3D_SDK_VERSION | 0x80000000
140c22c98:  callq d3dx9_43!D3DXCheckVersion
140c22c9d:  testl %eax, %eax
140c22c9f:  jne   ok
140c22ca1:  movl  $0xd, 0x3              ; crash
```

**Fix**

Ignore the debug bit, as native does (verified with the game's 64-bit build:
with this change it
gets past the check and renders its intro and menu):

```diff
 BOOL WINAPI D3DXCheckVersion(UINT d3d_sdk_ver, UINT d3dx_sdk_ver)
 {
-    return d3d_sdk_ver == D3D_SDK_VERSION && d3dx_sdk_ver == D3DX_SDK_VERSION;
+    /* Programs built with D3D_DEBUG_INFO pass D3D_SDK_VERSION | 0x80000000.
*/
+    return (d3d_sdk_ver & ~0x80000000u) == D3D_SDK_VERSION && d3dx_sdk_ver ==
D3DX_SDK_VERSION;
 }
```

A test in `dlls/d3dx9_36/tests/core.c` could check
`D3DXCheckVersion(D3D_SDK_VERSION | 0x80000000, D3DX_SDK_VERSION)`
on Windows to confirm native's exact rule (e.g. whether other high bits are
ignored too).

**Patch (for reference):**
https://github.com/codeWonderland/neutron/blob/main/tools/wine-dxmt/d3dx9-ch...

(Analysis and testing were done with AI assistance; the measurements are from
my own Mac. Patches are linked for reference.)

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