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-rw-r--r--advtrains/path.lua22
1 files changed, 15 insertions, 7 deletions
diff --git a/advtrains/path.lua b/advtrains/path.lua
index 23f5e78..ee82c06 100644
--- a/advtrains/path.lua
+++ b/advtrains/path.lua
@@ -286,16 +286,26 @@ 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 advtrains_path_get = advtrains.path_get
+
-- 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 start_index_f = atfloor(index)
+ local end_index_f = start_index_f + 1
+ local c_idx = atfloor(index + offset)
+ local c_idx_f = c_idx + 1
+
+ local frac = index - start_index_f
+
+ advtrains_path_get(train, math.min(start_index_f, end_index_f, c_idx, c_idx_f))
+ advtrains_path_get(train, math.max(start_index_f, end_index_f, c_idx, c_idx_f))
+
local dist1, dist2 = train.path_dist[start_index_f], train.path_dist[start_index_f+1]
- local start_dist = n_interpolate(dist1, dist2, frac)
+ local start_dist = dist1 + (dist2-dist1)*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)
+ local c_idx = atfloor(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.
@@ -306,9 +316,7 @@ function advtrains.path_get_index_by_offset(train, index, offset)
-- 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