[PATCH 2/2] ddraw/tests: Prefer D24S8 over D24X8.

[Stefan Dösinger]

It works better for depth readback on modern Radeon GPUs.

Signed-off-by: Stefan Dösinger <stefan at codeweavers.com>

---

Also compare to the readback mess that is test_depth_readback. On Nvidia
cards test_depth_readback is broken for D24S8, but works for some cards
with D16 or D24X8. That's not necessarily contradictory: test_depth_readback
draws actual geometry, whereas test_color_fill just uses DDBLT_DEPTHFILL.

If any Nvidia GPU I did not test now fails test_color_fill we can make
the chosen format card dependent. I'll avoid that for now though.
---
 dlls/ddraw/tests/ddraw4.c | 12 ++++++++++++
 dlls/ddraw/tests/ddraw7.c | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/dlls/ddraw/tests/ddraw4.c b/dlls/ddraw/tests/ddraw4.c
index a8b68b8a20b..451dabff20a 100644
--- a/dlls/ddraw/tests/ddraw4.c
+++ b/dlls/ddraw/tests/ddraw4.c
@@ -432,8 +432,20 @@ static HRESULT CALLBACK enum_z_fmt(DDPIXELFORMAT *format, void *ctx)
 {
     DDPIXELFORMAT *z_fmt = ctx;
 
+    /* Prefer higher Z precision over lower, and prefer D24S8 over
+     * D24X8. See also test_depth_readback for some GPU specific
+     * limitations. Note that test_depth_readback reads back depth
+     * values from draws, while users of this functions usually do
+     * not. */
     if (U1(*format).dwZBufferBitDepth > U1(*z_fmt).dwZBufferBitDepth)
+    {
         *z_fmt = *format;
+    }
+    else if (U1(*format).dwZBufferBitDepth == U1(*z_fmt).dwZBufferBitDepth
+            && U2(*format).dwStencilBitDepth > U2(*z_fmt).dwStencilBitDepth)
+    {
+        *z_fmt = *format;
+    }
 
     return DDENUMRET_OK;
 }
diff --git a/dlls/ddraw/tests/ddraw7.c b/dlls/ddraw/tests/ddraw7.c
index c7a38ab7701..fe09766eddb 100644
--- a/dlls/ddraw/tests/ddraw7.c
+++ b/dlls/ddraw/tests/ddraw7.c
@@ -455,8 +455,20 @@ static HRESULT CALLBACK enum_z_fmt(DDPIXELFORMAT *format, void *ctx)
 {
     DDPIXELFORMAT *z_fmt = ctx;
 
+    /* Prefer higher Z precision over lower, and prefer D24S8 over
+     * D24X8. See also test_depth_readback for some GPU specific
+     * limitations. Note that test_depth_readback reads back depth
+     * values from draws, while users of this functions usually do
+     * not. */
     if (U1(*format).dwZBufferBitDepth > U1(*z_fmt).dwZBufferBitDepth)
+    {
         *z_fmt = *format;
+    }
+    else if (U1(*format).dwZBufferBitDepth == U1(*z_fmt).dwZBufferBitDepth
+            && U2(*format).dwStencilBitDepth > U2(*z_fmt).dwStencilBitDepth)
+    {
+        *z_fmt = *format;
+    }
 
     return DDENUMRET_OK;
 }
-- 
2.34.1