Unduplicate the implementations of next power of two

Qtbase contains four identical implementations of next power of two,
these should be shared and the implementation made available to other
qt modules, as it is also used many places outside of qtbase.

[ChangeLog][QtCore][QtMath] Introduced qNextPowerOfTwo methods.

Change-Id: Id23fbe5ad6bae647b30d5a4212c0330e48a50278
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 2 insertions, 16 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 8223536608..d1417cfde5 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -1868,20 +1868,6 @@ QImage qt_gl_read_texture(const QSize &size, bool alpha_format, bool include_alp
     return img;
 }
 
-// returns the highest number closest to v, which is a power of 2
-// NB! assumes 32 bit ints
-int qt_next_power_of_two(int v)
-{
-    v--;
-    v |= v >> 1;
-    v |= v >> 2;
-    v |= v >> 4;
-    v |= v >> 8;
-    v |= v >> 16;
-    ++v;
-    return v;
-}
-
 Q_GLOBAL_STATIC(QGLTextureCache, qt_gl_texture_cache)
 
 QGLTextureCache::QGLTextureCache()
@@ -2462,8 +2448,8 @@ QGLTexture* QGLContextPrivate::bindTexture(const QImage &image, GLenum target, G
     // Scale the pixmap if needed. GL textures needs to have the
     // dimensions 2^n+2(border) x 2^m+2(border), unless we're using GL
     // 2.0 or use the GL_TEXTURE_RECTANGLE texture target
-    int tx_w = qt_next_power_of_two(image.width());
-    int tx_h = qt_next_power_of_two(image.height());
+    int tx_w = qNextPowerOfTwo(image.width() - 1);
+    int tx_h = qNextPowerOfTwo(image.height() - 1);
 
     QImage img = image;