Henri Verbeet : wined3d: Reimplement wined3d_ftoa().

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: b114a134134db73f1ac5aa693d8ff09b85d4411e
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=b114a134134db73f1ac5aa693d8ff09b85d4411e

Author: Henri Verbeet <hverbeet at codeweavers.com>
Date:   Fri Nov 22 10:45:00 2013 +0100

wined3d: Reimplement wined3d_ftoa().

The current implementation is not precise enough when the FPU is in REAL4
mode, which also happens to be the mode d3d9 sets by default. Doing the same
thing with integer math is a huge pain, so just replace the decimal separator
instead.
(cherry picked from commit 12f16f2127ffce9a05eedf008c3aa3732751a7e3)

---

 dlls/wined3d/utils.c |   47 +++++++----------------------------------------
 1 file changed, 7 insertions(+), 40 deletions(-)

diff --git a/dlls/wined3d/utils.c b/dlls/wined3d/utils.c
index 2ee4b95..a4b650d 100644
--- a/dlls/wined3d/utils.c
+++ b/dlls/wined3d/utils.c
@@ -3731,51 +3731,18 @@ void wined3d_get_draw_rect(const struct wined3d_state *state, RECT *rect)
         IntersectRect(rect, rect, &state->scissor_rect);
 }
 
-/* This should be equivalent to using the %.8e format specifier, but always
- * using '.' as decimal separator. This doesn't handle +/-INF or NAN, since
- * the GLSL and ARB parsers wouldn't be able to handle those anyway. */
+/* Print a floating point value with the %.8e format specifier, always using
+ * '.' as decimal separator. */
 void wined3d_ftoa(float value, char *s)
 {
-    int x, frac, exponent;
-    const char *sign = "";
-    double d;
+    int idx = 1;
 
-    d = value;
     if (copysignf(1.0f, value) < 0.0f)
-    {
-        d = -d;
-        sign = "-";
-    }
-
-    if (d == 0.0f)
-    {
-        x = 0;
-        frac = 0;
-        exponent = 0;
-    }
-    else
-    {
-        double t, diff;
-
-        exponent = floorf(log10f(d));
-        d /= pow(10.0, exponent);
-
-        x = d;
-        t = (d - x) * 100000000;
-        frac = t;
-        diff = t - frac;
-
-        if ((diff > 0.5) || (diff == 0.5 && (frac & 1)))
-        {
-            if (++frac >= 100000000)
-            {
-                frac = 0;
-                ++x;
-            }
-        }
-    }
+        ++idx;
 
-    sprintf(s, "%s%d.%08de%+03d", sign, x, frac, exponent);
+    sprintf(s, "%.8e", value);
+    if (isfinite(value))
+        s[idx] = '.';
 }
 
 void wined3d_release_dc(HWND window, HDC dc)