diff options
Diffstat (limited to 'advtrains')
| -rw-r--r-- | advtrains/path.lua | 91 | ||||
| -rw-r--r-- | advtrains/trainlogic.lua | 3 |
2 files changed, 61 insertions, 33 deletions
diff --git a/advtrains/path.lua b/advtrains/path.lua index 825e59b..ff034c9 100644 --- a/advtrains/path.lua +++ b/advtrains/path.lua @@ -17,12 +17,18 @@ -- path_cn - Connid of the current node that points towards path[i+1] -- path_cp - Connid of the current node that points towards path[i-1] -- When the day comes on that path!=node, these will only be set if this index represents a transition between rail nodes --- path_dist - The distance (in meters) between this (path[i]) and the next (path[i+1]) item of the path +-- path_dist - The total distance of this path element from path element 0 -- path_dir - The direction of this path item's transition to the next path item, which is the angle of conns[path_cn[i]].c --Variables: -- path_ext_f/b - how far path[i] is set -- path_trk_f/b - how far the path extends along a track. beyond those values, paths are generated in a straight line. -- path_req_f/b - how far path items were requested in the last step +-- +--Distance and index: +-- There is an important difference between the path index and the actual distance on the track: The distance between two path items can be larger than 1, +-- but the corresponding index increment is still 1. +-- Indexes in advtrains can be fractional values. If they are, it means that the actual position is interpolated between the 2 adjacent path items. +-- If you need to proceed along the path by a specific actual distance, it does NOT work to simply add it to the index. You should use the path_get_index_by_offset() function. -- creates the path data structure, reconstructing the train from a position and a connid -- Important! train.drives_on must exist while calling this method @@ -40,7 +46,7 @@ function advtrains.path_create(train, pos, connid, rel_index) train.path = { [0] = { x=posr.x, y=posr.y+rhe, z=posr.z } } train.path_cn = { [0] = connid } train.path_cp = { [0] = mconnid } - train.path_dist = {} + train.path_dist = { [0] = 0 } train.path_dir = { [0] = advtrains.conn_angle_median(conns[mconnid].c, conns[connid].c) @@ -135,12 +141,12 @@ function advtrains.path_print(train, printf) printf("path_print: Path is invalidated/inexistant.") return end - printf("i: CP Position Dir CN ->Dist->") + printf("i: CP Position Dir CN Dist") for i = train.path_ext_b, train.path_ext_f do if i==train.path_trk_b then printf("--Back on-track border here--") end - printf(i,": ",train.path_cp[i]," ",train.path[i]," ",train.path_dir[i]," ",train.path_cn[i]," ->",train.path_dist[i],"->") + printf(i,": ",train.path_cp[i]," ",train.path[i]," ",train.path_dir[i]," ",train.path_cn[i]," ",train.path_dist[i],"") if i==train.path_trk_f then printf("--Front on-track border here--") end @@ -156,7 +162,9 @@ function advtrains.path_get(train, index) if index ~= atfloor(index) then error("For train "..train.id..": Called path_get() but index="..index.." is not a round number") end + local pef = train.path_ext_f + -- generate forward (front of train, positive) while index > pef do local pos = train.path[pef] local connid = train.path_cn[pef] @@ -183,10 +191,13 @@ function advtrains.path_get(train, index) train.path_dir[pef] = train.path_dir[pef-1] end train.path[pef] = adj_pos - train.path_dist[pef - 1] = vector.distance(pos, adj_pos) + train.path_dist[pef] = train.path_dist[pef-1] + vector.distance(pos, adj_pos) end train.path_ext_f = pef + + local peb = train.path_ext_b + -- generate backward (back of train, negative) while index < peb do local pos = train.path[peb] local connid = train.path_cp[peb] @@ -213,7 +224,7 @@ function advtrains.path_get(train, index) train.path_dir[peb] = train.path_dir[peb+1] end train.path[peb] = adj_pos - train.path_dist[peb] = vector.distance(pos, adj_pos) + train.path_dist[peb] = train.path_dist[peb+1] - vector.distance(pos, adj_pos) end train.path_ext_b = peb @@ -256,37 +267,53 @@ function advtrains.path_get_adjacent(train, index) return p_floor, p_ceil, frac end +local function n_interpolate(s, e, f) + return s + (e-s)*f +end + +-- This function determines the index resulting from moving along the path by 'offset' meters +-- starting from 'index'. See also the comment on the top of the file. function advtrains.path_get_index_by_offset(train, index, offset) - local off = offset - local idx = atfloor(index) - -- go down to floor. Calculate required path_dist - advtrains.path_get_adjacent(train, idx) - off = off + ((index-idx) * train.path_dist[idx]) - --atdebug("pibo: 1 off=",off,"idx=",idx," index=",index) + -- Step 1: determine my current absolute pos on the path + local start_index_f = math.floor(index) + local _, _, frac = advtrains.path_get_adjacent(train, index) + local dist1, dist2 = train.path_dist[start_index_f], train.path_dist[start_index_f+1] + local start_dist = n_interpolate(dist1, dist2, frac) + + -- Step 2: determine the total end distance and estimate the index we'd come out + local end_dist = start_dist + offset + + local c_idx = math.floor(index + offset) + + -- Step 3: move forward/backward to find real index + -- We assume here that the distance between 2 path items is never smaller than 1. + -- Our estimated index is therefore either exact or too far over, and we're going to go back + -- towards the origin. It is therefore sufficient to query path_get a single time - -- then walk the path back until we overshoot (off becomes >=0) - while off<0 do - idx = idx - 1 - advtrains.path_get_adjacent(train, idx) - off = off + train.path_dist[idx] + -- How we'll adjust c_idx + -- Desired position: -------#------ + -- Path items : --|--|--|--|-- + -- c_idx : ^ + + advtrains.path_get_adjacent(train, c_idx) + + while train.path_dist[c_idx] < end_dist do + c_idx = c_idx + 1 end - --atdebug("pibo: 2 off=",off,"idx=",idx) - -- then walk the path forward until we would overshoot - while off - train.path_dist[idx] >= 0 do - idx = idx + 1 - advtrains.path_get_adjacent(train, idx) - if not train.path_dist[idx] then - for i=-5,5 do - atdebug(idx+i,train.path_dist[idx+i]) - end - end - off = off - train.path_dist[idx] + + while train.path_dist[c_idx] > end_dist do + c_idx = c_idx - 1 end - --atdebug("pibo: 3 off=",off,"idx=",idx," returns:",idx + (off / train.path_dist[idx])) - -- we should now be on the floor of the index we actually want. - -- give them the rest! - return idx + (off / train.path_dist[idx]) + -- Step 4: now c_idx points to the place shown above. Find out the fractional part. + + dist1, dist2 = train.path_dist[c_idx], train.path_dist[c_idx+1] + + frac = (end_dist - dist1) / (dist2 - dist1) + + assert(frac>=0 and frac<1, frac) + + return c_idx + frac end local PATH_CLEAR_KEEP = 4 diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua index bc24feb..3c0d02e 100644 --- a/advtrains/trainlogic.lua +++ b/advtrains/trainlogic.lua @@ -474,7 +474,8 @@ function advtrains.train_step_b(id, train, dtime) --- 4. move train --- - local pdist = train.path_dist[math.floor(train.index)] or 1 + local idx_floor = math.floor(train.index) + local pdist = (train.path_dist[idx_floor+1] - train.path_dist[idx_floor]) local distance = (train.velocity*dtime) / pdist --debugging code |