dix: improve readbility of DoGetDirection.
Use enums for the direction bits, not hardcoded bitfield values that are added up. Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> Reviewed-by: Daniel Stone <daniel@fooishbar.org> Reviewed-by: Jamey Sharp <jamey@minilop.net> Reviewed-by: Simon Thum <simon.thum@gmx.de>
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@ -429,14 +429,27 @@ InitTrackers(DeviceVelocityPtr vel, int ntracker)
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vel->num_tracker = ntracker;
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}
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enum directions {
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N = (1 << 0),
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NE = (1 << 1),
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E = (1 << 2),
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SE = (1 << 3),
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S = (1 << 4),
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SW = (1 << 5),
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W = (1 << 6),
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NW = (1 << 7),
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UNDEFINED = 0xFF
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};
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/**
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* return a bit field of possible directions.
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* 0 = N, 2 = E, 4 = S, 6 = W, in-between is as you guess.
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* There's no reason against widening to more precise directions (<45 degrees),
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* should it not perform well. All this is needed for is sort out non-linear
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* motion, so precision isn't paramount. However, one should not flag direction
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* too narrow, since it would then cut the linear segment to zero size way too
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* often.
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*
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* @return A bitmask for N, NE, S, SE, etc. indicating the directions for
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* this movement.
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*/
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static int
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DoGetDirection(int dx, int dy){
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@ -446,23 +459,23 @@ DoGetDirection(int dx, int dy){
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if(abs(dx) < 2 && abs(dy) < 2){
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/* first check diagonal cases */
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if(dx > 0 && dy > 0)
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return 4+8+16;
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return E | SE | S;
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if(dx > 0 && dy < 0)
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return 1+2+4;
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return N | NE | E;
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if(dx < 0 && dy < 0)
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return 1+128+64;
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return W | NW | N;
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if(dx < 0 && dy > 0)
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return 16+32+64;
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return W | SW | S;
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/* check axis-aligned directions */
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if(dx > 0)
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return 2+4+8; /*E*/
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return NE | E | SE;
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if(dx < 0)
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return 128+64+32; /*W*/
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return NW | W | SW;
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if(dy > 0)
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return 32+16+8; /*S*/
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return SE | S | SW;
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if(dy < 0)
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return 128+1+2; /*N*/
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return 255; /* shouldn't happen */
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return NE | N | NW;
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return UNDEFINED; /* shouldn't happen */
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}
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/* else, compute angle and set appropriate flags */
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#ifdef _ISOC99_SOURCE
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@ -478,7 +491,7 @@ DoGetDirection(int dx, int dy){
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i1 = (int)(r+0.1) % 8;
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i2 = (int)(r+0.9) % 8;
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if(i1 < 0 || i1 > 7 || i2 < 0 || i2 > 7)
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return 255; /* shouldn't happen */
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return UNDEFINED; /* shouldn't happen */
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return 1 << i1 | 1 << i2;
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}
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@ -558,7 +571,7 @@ CalcTracker(DeviceVelocityPtr vel, int offset, int cur_t){
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*/
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static float
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QueryTrackers(DeviceVelocityPtr vel, int cur_t){
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int n, offset, dir = 255, i = -1, age_ms;
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int n, offset, dir = UNDEFINED, i = -1, age_ms;
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/* initial velocity: a low-offset, valid velocity */
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float iveloc = 0, res = 0, tmp, vdiff;
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float vfac = vel->corr_mul * vel->const_acceleration; /* premultiply */
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