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Fixed bug #920

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From Martin:

Alright... I corrected SDL_SYS_ToDirection in SDL_syshaptic.c in the linux
directory of haptic. Now in all 3 cases the same value is returned, at least.
Therefore now it should behave the same way as on Windows.

I added some comments and corrected the cases SDL_HAPTIC_CARTESIAN and
SDL_HAPTIC_SPHERICAL.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%404433
This commit is contained in:
Sam Lantinga 2010-01-18 14:57:41 +00:00
parent a448d86eb8
commit 1d8567b304
1 changed files with 36 additions and 11 deletions
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47
src/haptic/linux/SDL_syshaptic.c
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@ -505,20 +505,45 @@ SDL_SYS_ToDirection(SDL_HapticDirection * dir)
switch (dir->type) { switch (dir->type) {
case SDL_HAPTIC_POLAR: case SDL_HAPTIC_POLAR:
/* Linux directions are inverted. */ /* Linux directions start from south.
tmp = (((18000 + dir->dir[0]) % 36000) * 0xFFFF) / 36000; (and range from 0 to 0xFFFF)
Quoting include/linux/input.h, line 926:
Direction of the effect is encoded as follows:
0 deg -> 0x0000 (down)
90 deg -> 0x4000 (left)
180 deg -> 0x8000 (up)
270 deg -> 0xC000 (right)
*/
tmp = (((18000 + dir->dir[0]) % 36000) * 0xFFFF) / 36000; // convert to range [0,0xFFFF]
return (Uint16) tmp;
case SDL_HAPTIC_SPHERICAL:
/*
We convert to polar, because that's the only supported direction on Linux.
The first value of a spherical direction is practically the same as a
Polar direction, except that we have to add 90 degrees. It is the angle
from EAST {1,0} towards SOUTH {0,1}.
--> add 9000
--> finally add 18000 and convert to [0,0xFFFF] as in case SDL_HAPTIC_POLAR.
*/
tmp = ((dir->dir[0]) + 9000) % 36000; /* Convert to polars */
tmp = (((18000 + tmp) % 36000) * 0xFFFF) / 36000; // convert to range [0,0xFFFF]
return (Uint16) tmp; return (Uint16) tmp;
case SDL_HAPTIC_CARTESIAN: case SDL_HAPTIC_CARTESIAN:
/* We must invert "x" and "y" to go clockwise. */ f = atan2(dir->dir[1], dir->dir[0]);
f = atan2(dir->dir[0], dir->dir[1]); /*
tmp = (int) (f * 18000. / M_PI) % 36000; atan2 takes the parameters: Y-axis-value and X-axis-value (in that order)
tmp = (tmp * 0xFFFF) / 36000; - Y-axis-value is the second coordinate (from center to SOUTH)
return (Uint16) tmp; - X-axis-value is the first coordinate (from center to EAST)
We add 36000, because atan2 also returns negative values. Then we practically
case SDL_HAPTIC_SPHERICAL: have the first spherical value. Therefore we proceed as in case
tmp = (36000 - dir->dir[0]) + 27000; /* Convert to polars */ SDL_HAPTIC_SPHERICAL and add another 9000 to get the polar value.
tmp = (((18000 + tmp) % 36000) * 0xFFFF) / 36000; --> add 45000 in total
--> finally add 18000 and convert to [0,0xFFFF] as in case SDL_HAPTIC_POLAR.
*/
tmp = (((int) (f * 18000. / M_PI)) + 45000) % 36000;
tmp = (((18000 + tmp) % 36000) * 0xFFFF) / 36000; // convert to range [0,0xFFFF]
return (Uint16) tmp; return (Uint16) tmp;
default: default: