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Code Issues

(svn r19671) -Fix (r19670): RoundDiv() needs to deal with signed numerators.

release/1.1
frosch 2010-04-18 17:13:01 +00:00
parent 2e90f7f8b9
commit af7051178d
3 changed files with 13 additions and 7 deletions
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12
src/core/math_func.hpp
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@ -330,14 +330,20 @@ static FORCEINLINE uint CeilDiv(uint a, uint b)
} }
/** /**
* Computes round(a / b) for non-negative a and b. * Computes round(a / b) for signed a and unsigned b.
* @param a Numerator * @param a Numerator
* @param b Denominator * @param b Denominator
* @return Quotient, rounded to nearest * @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 */ #endif /* MATH_FUNC_HPP */

4
src/gfx.cpp
View File

@ -550,7 +550,7 @@ static int DrawString(int left, int right, int top, char *str, const char *last,
break; break;
case SA_CENTER: 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 + 1 = left + w */
right = left + w - 1; right = left + w - 1;
break; break;
@ -823,7 +823,7 @@ int DrawStringMultiLine(int left, int right, int top, int bottom, StringID str,
total_height = (num + 1) * mt; 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; const char *src = buffer;
for (;;) { for (;;) {

4
src/terraform_gui.cpp
View File

@ -649,8 +649,8 @@ struct ScenarioEditorLandscapeGenerationWindow : Window {
{ {
if (widget != ETTW_DOTS) return; if (widget != ETTW_DOTS) return;
int center_x = RoundDiv(r.left + r.right, 2); int center_x = RoundDivSU(r.left + r.right, 2);
int center_y = RoundDiv(r.top + r.bottom, 2); int center_y = RoundDivSU(r.top + r.bottom, 2);
int n = _terraform_size * _terraform_size; int n = _terraform_size * _terraform_size;
const int8 *coords = &_multi_terraform_coords[0][0]; const int8 *coords = &_multi_terraform_coords[0][0];