Henri Verbeet : wined3d: Use a simpler way to calculate the number of texture levels.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 7d29aecd6fa0fb3c541f318ad50a442f47e0c732
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=7d29aecd6fa0fb3c541f318ad5...

Author: Henri Verbeet <hverbeet(a)codeweavers.com>
Date:   Fri Dec 12 09:33:52 2008 +0100

wined3d: Use a simpler way to calculate the number of texture levels.

It's probably slightly faster too.

---

 dlls/wined3d/device.c          |   28 +++-------------------------
 dlls/wined3d/utils.c           |   26 ++++++++++++++++++++++++++
 dlls/wined3d/wined3d_private.h |    1 +
 3 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/dlls/wined3d/device.c b/dlls/wined3d/device.c
index d091b58..a99ff56 100644
--- a/dlls/wined3d/device.c
+++ b/dlls/wined3d/device.c
@@ -855,15 +855,7 @@ static HRESULT  WINAPI IWineD3DDeviceImpl_CreateTexture(IWineD3DDevice *iface, U
         }
         object->baseTexture.levels = 1;
     } else if (Levels == 0) {
-        TRACE("calculating levels %d\n", object->baseTexture.levels);
-        object->baseTexture.levels++;
-        tmpW = Width;
-        tmpH = Height;
-        while (tmpW > 1 || tmpH > 1) {
-            tmpW = max(1, tmpW >> 1);
-            tmpH = max(1, tmpH >> 1);
-            object->baseTexture.levels++;
-        }
+        object->baseTexture.levels = wined3d_log2i(max(Width, Height)) + 1;
         TRACE("Calculated levels = %d\n", object->baseTexture.levels);
     }
 
@@ -958,16 +950,7 @@ static HRESULT WINAPI IWineD3DDeviceImpl_CreateVolumeTexture(IWineD3DDevice *ifa
         }
         object->baseTexture.levels = 1;
     } else if (Levels == 0) {
-        object->baseTexture.levels++;
-        tmpW = Width;
-        tmpH = Height;
-        tmpD = Depth;
-        while (tmpW > 1 || tmpH > 1 || tmpD > 1) {
-            tmpW = max(1, tmpW >> 1);
-            tmpH = max(1, tmpH >> 1);
-            tmpD = max(1, tmpD >> 1);
-            object->baseTexture.levels++;
-        }
+        object->baseTexture.levels = wined3d_log2i(max(max(Width, Height), Depth)) + 1;
         TRACE("Calculated levels = %d\n", object->baseTexture.levels);
     }
 
@@ -1117,12 +1100,7 @@ static HRESULT WINAPI IWineD3DDeviceImpl_CreateCubeTexture(IWineD3DDevice *iface
         }
         object->baseTexture.levels = 1;
     } else if (Levels == 0) {
-        object->baseTexture.levels++;
-        tmpW = EdgeLength;
-        while (tmpW > 1) {
-            tmpW = max(1, tmpW >> 1);
-            object->baseTexture.levels++;
-        }
+        object->baseTexture.levels = wined3d_log2i(EdgeLength) + 1;
         TRACE("Calculated levels = %d\n", object->baseTexture.levels);
     }
 
diff --git a/dlls/wined3d/utils.c b/dlls/wined3d/utils.c
index 7fc874b..f65bcdc 100644
--- a/dlls/wined3d/utils.c
+++ b/dlls/wined3d/utils.c
@@ -2245,3 +2245,29 @@ BOOL ffp_frag_program_key_compare(const void *keya, const void *keyb)
 
     return memcmp(ka, kb, sizeof(*ka)) == 0;
 }
+
+UINT wined3d_log2i(UINT32 x)
+{
+    static const BYTE l[] =
+    {
+        0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+        4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+    };
+    UINT32 i;
+
+    return (i = x >> 16) ? (x = i >> 8) ? l[x] + 24 : l[i] + 16 : (i = x >> 8) ? l[i] + 8 : l[x];
+}
diff --git a/dlls/wined3d/wined3d_private.h b/dlls/wined3d/wined3d_private.h
index e28bb6d..0b444bb 100644
--- a/dlls/wined3d/wined3d_private.h
+++ b/dlls/wined3d/wined3d_private.h
@@ -2031,6 +2031,7 @@ BOOL getDepthStencilBits(WINED3DFORMAT fmt, short *depthSize, short *stencilSize
 /* Math utils */
 void multiply_matrix(WINED3DMATRIX *dest, const WINED3DMATRIX *src1, const WINED3DMATRIX *src2);
 unsigned int count_bits(unsigned int mask);
+UINT wined3d_log2i(UINT32 x);
 
 /*****************************************************************************
  * To enable calling of inherited functions, requires prototypes