Mercurial > hg > openttd
changeset 15051:11b01bb094e0 draft
(svn r19671) -Fix (r19670): RoundDiv() needs to deal with signed numerators.
| author | frosch <frosch@openttd.org> |
|---|---|
| date | Sun, 18 Apr 2010 17:13:01 +0000 |
| parents | 73f4e0e490b7 |
| children | f0686cdc3f45 |
| files | src/core/math_func.hpp src/gfx.cpp src/terraform_gui.cpp |
| diffstat | 3 files changed, 13 insertions(+), 7 deletions(-) [+] |
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--- a/src/core/math_func.hpp +++ b/src/core/math_func.hpp @@ -330,14 +330,20 @@ } /** - * Computes round(a / b) for non-negative a and b. + * Computes round(a / b) for signed a and unsigned b. * @param a Numerator * @param b Denominator * @return Quotient, rounded to nearest */ -static FORCEINLINE uint RoundDiv(uint a, uint b) +static FORCEINLINE int RoundDivSU(int a, uint b) { - return (a + b / 2) / b; + if (a > 0) { + /* 0.5 is rounded to 1 */ + return (a + (int)b / 2) / (int)b; + } else { + /* -0.5 is rounded to 0 */ + return (a - ((int)b - 1) / 2) / (int)b; + } } #endif /* MATH_FUNC_HPP */
--- a/src/gfx.cpp +++ b/src/gfx.cpp @@ -550,7 +550,7 @@ break; case SA_CENTER: - left = RoundDiv(initial_right + 1 + initial_left - w, 2); + left = RoundDivSU(initial_right + 1 + initial_left - w, 2); /* right + 1 = left + w */ right = left + w - 1; break; @@ -823,7 +823,7 @@ total_height = (num + 1) * mt; } - int y = (align == SA_CENTER) ? RoundDiv(bottom + top - total_height, 2) : top; + int y = (align == SA_CENTER) ? RoundDivSU(bottom + top - total_height, 2) : top; const char *src = buffer; for (;;) {
--- a/src/terraform_gui.cpp +++ b/src/terraform_gui.cpp @@ -649,8 +649,8 @@ { if (widget != ETTW_DOTS) return; - int center_x = RoundDiv(r.left + r.right, 2); - int center_y = RoundDiv(r.top + r.bottom, 2); + int center_x = RoundDivSU(r.left + r.right, 2); + int center_y = RoundDivSU(r.top + r.bottom, 2); int n = _terraform_size * _terraform_size; const int8 *coords = &_multi_terraform_coords[0][0];