AP_Scripting: re-work multi-point roll using roll_sequence

libraries/AP_Scripting/applets/Aerobatics/FixedWing/README.md

@@ -42,15 +42,12 @@ the ground track.
 | 19 | Stall Turn               | radius | height      | direction   |            | Yes        |
 | 20 | Procedure Turn           | radius | bank angle  | step-out    |            | Yes        |
 | 21 | Derry Turn               | radius | bank angle  |             |            | No         |
-| 22 | Two Point Roll           | length |             |             |            | No         |
 | 23 | Half Climbing Circle     | radius | height      | bank angle  |            | Yes        |
 | 24 | Crossbox Humpty          | radius | height      |             |            | Yes        |
 | 25 | Laydown Humpty           | radius | height      |             |            | Yes        |
 | 25 | Barrel Roll              | radius | length      | num spirals |            | No         |
 | 26 | Straight Hold            | length | bank angle  |             |            | No         |
-| 29 | Four Point Roll          | length |             |             |            | No         |
-| 30 | Eight Point Roll         | length |             |             |            | No         |
-| 31 | Multi Point Roll         | length | num points  |             |            | No         |
+| 31 | Multi Point Roll         | length | num points  | hold frac   |            | No         |
 
 Note: In the script you will find other (specialised) manouvers which do not appear in the 
 'command table'. These tend to be specialised manouvers which may expect an inverted entry or 

libraries/AP_Scripting/applets/Aerobatics/FixedWing/plane_aerobatics.lua

@@ -1220,28 +1220,39 @@ function vertical_aerobatic_box(total_length, total_width, r, bank_angle)
    })
 end
 
-function multi_point_roll(length, N, arg3, arg4)
-   local paths = {}
-   local len_roll = length * (N-1) / (N*4-1)
-   local len_hold = length / (N*4-1)
-   local ang = 360 / N
-   for i = 1, N do
-      paths[#paths+1] = { path_straight(len_roll), roll_angle(ang) }
-      paths[#paths+1] = { path_straight(len_hold), roll_angle(0) }
+--[[
+   a multi-point roll
+     - length = total length of straight flight
+     - N = number of points of roll for full 360
+     - hold_frac = proportion of each segment to hold attitude, will use 0.2 if 0
+     - num_points = number of points of the N point roll to do, will use N if 0
+
+   Note that num_points can be greater than N, for example do 6 points
+   of a 4 point roll, resulting in inverted flight
+--]]
+function multi_point_roll(length, N, hold_frac, num_points)
+   if hold_frac <= 0 then
+      hold_frac = 0.2
    end
-   return make_paths("multi_point_roll", paths)
-end
-
-function two_point_roll(length, arg2, arg3, arg4)
-   return multi_point_roll(length, 2)
-end
-
-function four_point_roll(length, arg2, arg3, arg4)
-   return multi_point_roll(length, 4)
+   if num_points <= 0 then
+      num_points = N
+   end
+   --[[
+      construct a roll sequence to use over the full length
+   --]]
+   local seq = {}
+   local roll_frac = 1.0 - hold_frac
+   for i = 1, num_points do
+      seq[#seq+1] = { roll_frac, 360 / N }
+      if i < num_points then
+         seq[#seq+1] = { hold_frac, 0 }
+      end
+   end
+   return make_paths("multi_point_roll", {{ path_straight(length), roll_sequence(seq) }})
 end
 
 function eight_point_roll(length, arg2, arg3, arg4)
-   return multi_point_roll(length, 8)
+   return multi_point_roll(length, 8, 0.5)
 end
 
 function procedure_turn(radius, bank_angle, step_out, arg4)
@@ -1556,7 +1567,7 @@ function nz_clubman()                               -- positioned for a flight l
           { straight_align,           { -180, 0 } },
           { half_reverse_cuban_eight, { 90 } },
           { straight_align,           { -120, 0 } },
-          { two_point_roll,           { 240 },         message="Two Point Roll"},
+          { multi_point_roll,         { 240, 2, 0.5 }, message="Two Point Roll"},
           { straight_align,           { 150, 0 } },
           { half_reverse_cuban_eight, { 90 } },
           { straight_align,           { 106, 0 } },
@@ -2360,15 +2371,15 @@ command_table[18]= PathFunction(downline_45, "Downline-45")
 command_table[19]= PathFunction(stall_turn, "Stall Turn")
 command_table[20]= PathFunction(procedure_turn, "Procedure Turn")
 command_table[21]= PathFunction(derry_turn, "Derry Turn")
-command_table[22]= PathFunction(two_point_roll, "Two Point Roll")
+-- 22 was Two Point Roll - use multi point roll instead
 command_table[23]= PathFunction(half_climbing_circle, "Half Climbing Circle")
 command_table[24]= PathFunction(crossbox_humpty, "Crossbox Humpty")
 command_table[25]= PathFunction(laydown_humpty, "Laydown Humpty")
 command_table[26]= PathFunction(barrel_roll, "Barrel Roll")
 command_table[27]= PathFunction(straight_flight, "Straight Hold")
 command_table[28]= PathFunction(partial_circle, "Partial Circle")
-command_table[29]= PathFunction(four_point_roll, "Four Point Roll")
-command_table[30]= PathFunction(eight_point_roll, "Eight Point Roll")
+-- 29 was Four Point Roll - use multi point roll instead
+-- 30 was Eight Point Roll - use multi point roll instead
 command_table[31]= PathFunction(multi_point_roll, "Multi Point Roll")
 command_table[32]= PathFunction(side_step, "Side Step")
 command_table[200] = PathFunction(test_all_paths, "Test Suite")