Henri Verbeet : ddraw: Use wined3d_bit_scan() in compute_sphere_visibility().

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 996cfb841ef5618f78400d42a862d2015ff37536
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=996cfb841ef5618f78400d42a...

Author: Henri Verbeet 
Date:   Wed Nov 10 11:36:08 2021 +0100

ddraw: Use wined3d_bit_scan() in compute_sphere_visibility().

Rémi Bernon reports an unspecified issue with gcc 11 related to
compute_sphere_visibility() expecting 12 input planes, but
d3d_device3_ComputeSphereVisibility() only providing 6. The actual number of
planes required depends on the "enabled_planes" mask. This patch should make
the code better reflect that, but I do not have a gcc 11 setup to verify it
resolves the issue there.

Signed-off-by: Henri Verbeet 
Signed-off-by: Alexandre Julliard

---

dlls/ddraw/device.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/dlls/ddraw/device.c b/dlls/ddraw/device.c
index 8afbab0e58d..6e8f109173b 100644
--- a/dlls/ddraw/device.c
+++ b/dlls/ddraw/device.c
@@ -4638,17 +4638,20 @@ static void prepare_clip_space_planes(struct d3d_device *device, struct wined3d_
     plane[5].w = m._44 - m._43;
 }

-static void compute_sphere_visibility(struct wined3d_vec4 plane[12], DWORD enabled_planes, BOOL equality,
-        D3DVECTOR *centers, D3DVALUE *radii, DWORD sphere_count, DWORD *return_values)
+static void compute_sphere_visibility(const struct wined3d_vec4 *planes, DWORD enabled_planes, BOOL equality,
+        const D3DVECTOR *centres, const D3DVALUE *radii, unsigned int sphere_count, DWORD *return_values)
 {
-    UINT i, j;
+    unsigned int mask, i, j;

+    memset(return_values, 0, sphere_count * sizeof(*return_values));
     for (i = 0; i < sphere_count; ++i)
     {
-        return_values[i] = 0;
-        for (j = 0; j < 12; ++j)
-            if (enabled_planes & 1u << j)
-                return_values[i] |= in_plane(j, plane[j], centers[i], radii[i], equality);
+        mask = enabled_planes;
+        while (mask)
+        {
+            j = wined3d_bit_scan(&mask);
+            return_values[i] |= in_plane(j, planes[j], centres[i], radii[i], equality);
+        }
     }
 }