NewGRF Road Stops Addition to NewGRF Specifications in JGR's Patchpack

This document describes the non-standard addition of the NewGRF road stops feature to the Official OpenTTD NewGRF Specifications, as implemented in this patchpack.
This feature does not match OpenTTD PR #7955 in a number of key areas, this feature may not necessarily match implementations of NewGRF road stops in other patches, branches, etc.
This feature as implemented here MAY also be present in other patchpacks.

See the NewGRF additions document for background information on additions to the NewGRF specifications.

A subset of the functionality listed below is also supported in a fork of NML, see the associated NML road stops and NML additions documents for more details.

NewGRFs which use this feature SHOULD use the feature testing mechanism to check whether the road stop feature and/or feature ID mapping is supported.

NewGRFs which use this feature MUST use the feature ID mapping mechanism to map the non-standard NewGRF road stop feature to a local feature ID.

This feature is indicated by the feature name: road_stops, version 1.
The feature name to use for feature ID mapping is road_stops.
Features/properties/variables which require a higher version will indicate the required version. Unless indicated otherwise these will fall back to doing nothing on versions which do not support them.

Actions:

• Action 0
• Action 2
• Variational Action 2
• Random Action 2
• Action 3

Action 0 - Road Stops

See the Action 0 Specification for background information.

Road stop class ID (08, or mappable property: roadstop_class_id)

This property sets the road stop class ID for this road stop ID.
This property must be used first before any other property for this road stop ID.
Two class names are pre-defined:

Road stop type availability (09, or mappable property: roadstop_stop_type)

This property sets the road stop type availability, this is ignored for road stops in the WAYP class.
The property length is 1 byte. The format is:

Road stop name (0A, or mappable property: roadstop_stop_name)

This property sets the road stop name string ID.
The property length is 2 bytes. This should be a D8xx or DCxx string ID.

Road stop class name (0B, or mappable property: roadstop_class_name)

This property sets the road stop class name string ID.
The property length is 2 bytes. This should be a D8xx or DCxx string ID.

Road stop draw mode (0C, or mappable property: roadstop_draw_mode)

This property sets the road stop draw mode.
The property length is 1 byte. The format is:

Road stop random trigger cargoes (0D, or mappable property: roadstop_random_trigger_cargoes)

This property sets the cargo types for random triggers.
This functions the same way as station (feature 4) property 12.
This sets which cargo types should trigger re-randomizing. The cargo types are given as a bitmask of the bits from column 3 (type B) in CargoTypes. If nothing is set (the default), the no random triggers will happen, to conserve CPU time.
With GRF version 7 and above, the interpretation of bits changes. Instead of climate-dependent cargo slot numbers (type B), you have to set the bits of climate-independent cargo ID (type A).
The property length is 4 bytes.

Road stop animation info (0E, or mappable property: roadstop_animation_info)

This property sets the cargo types for random triggers.
This functions the same way as station (feature 4) property 16.
The low byte specifies the number of animation frames minus one, so 00 means 1 frame, 01 means 2 frames etc. The maximum number of frames is 256, although you can have some problems if your animation exceeds FD (253) frames. The high byte must be 0 for non-looping animations and 01 for looping animations. Every other value is reserved for future use. In addition, if the whole word contains FFFF, animation is turned off for this station (this is the default value). Since you can't have properties for individual station tiles, this property applies for every tile of the station. If you don't want to animate some tiles, you should check the current position during callback 140 and return FD if the current tile doesn't need to be animated. If you also need animations of different length per tile, you'll have to use callback 141 for that.
The property length is 2 bytes.

Road stop animation speed (0F, or mappable property: roadstop_animation_speed)

This property sets the cargo types for random triggers.
This functions the same way as station (feature 4) property 17.
This is the amount of time between switching frames. The default value is 2, which means the switch occurs every 108 milliseconds. Increasing this value by one doubles the wait, i.e. 3 will cause 216 ms delay, while 4 will pause 432 ms, and so on. The minimum is 0, which means the fastest possible animation, changing frames every game tick (27ms). The maximum is 16, which means 1769 seconds (approx. half an hour) delay. Settings above this value may cause strange behaviour.
The property length is 1 byte.

Road stop animation triggers (10, or mappable property: roadstop_animation_triggers)

This property sets the cargo types for random triggers.
This functions the same way as station (feature 4) property 18.
This is a bit mask of events that should trigger callback 140, allowing to change the animation state.

Road stop callback flags (11, or mappable property: roadstop_callback_mask)

This property enables callbacks for this road stop type.
The property length is 1 byte. The format is:

Road stop general flags (12, or mappable property: roadstop_general_flags)

This property sets general flags for this road stop type.
The property length is 4 bytes. The format is:

Road stop minimum bridge heights (13, or mappable property: roadstop_min_bridge_height)

This property allows or disallows building bridges over road stops.
The bridge height property defines minimum clearances required for a bridge for each of the 6 views/rotations (or 0 to not allow any bridge). Values are given in height level units (1 level == 8px).
Each height value is 1 byte, the total property length is 6 bytes.

Road stop disallowed bridge pillars (14, or mappable property: roadstop_disallowed_bridge_pillars)

This property describes which bridge pillars are not allowed on the road stop tile.
It consists of a set of pillar flags, for each of the 6 road stop views/rotations.
Each set of flags is 1 byte, the total property length is 6 bytes.
Each set of flags has the format described in the bridge_pillar_flags property section.

Road stop cost multipliers (15, or mappable property: roadstop_cost_multipliers)

This property sets the build and removal cost multipliers.
The first byte is the build cost multiplier.
The second byte is the removal cost multiplier.
The total property length is 2 bytes.
A value of 16 produces a build or removal cost the same as non-NewGRF road stops..

Action 2 - Road Stops

See the Action 2 Specification for background information.

Road stops use the special sprite layout format, the same as Action 2 features: 7 (house), 9 (industry tile), F (object), 11 (airport tile).

Variational Action 2 - Road Stops

See the Variational Action 2 Specification for background information.

The parent scope for this feature is the road stop's station's town.

Road stop view/rotation (40, or mappable variable: roadstop_view)

Bits 0 - 7 have the range 0 - 5, see the 6 road stop views/rotations
The remaining bits are reserved for future use and should be masked.

Road stop type (41, or mappable variable: roadstop_type)

Bits 0 - 7 have the values in the table below.

Road stop tile terrain type (42, or mappable variable: roadstop_terrain_type)

This has the same value as bits 0 - 7 of object (feature F) variable 41.

Road stop road type (43, or mappable variable: roadstop_road_type)

This has the value of the (translated) roadtype the road stop is built on, or the current roadtype in the build GUI. If the roadtype has no entry in the roadtype translation table of the GRF, this value will be 0xFF. If no translation table is present, the raw value will be returned. Note: only exact matches of roadtypes are reported. If the translation table of the GRF does not contain the exact roadtype 0xFF is returned.
If the tile has no road at all (tram only) 0xFFFFFFFF is returned.

Road stop tram type (44, or mappable variable: roadstop_road_type)

This has the value of the (translated) tramtype the road stop is built on, or the current tramtype in the build GUI. If the tramtype has no entry in the tramtype translation table of the GRF, this value will be 0xFF. If no translation table is present, the raw value will be returned. Note: only exact matches of tramtypes are reported. If the translation table of the GRF does not contain the exact tramtype 0xFF is returned.
If the tile has no tram at all (road only) 0xFFFFFFFF is returned.

Town zone and Manhattan distance of town (45, or mappable variable: roadstop_town_zone)

The town used is the one associated with the station/waypoint (this is in the station/waypoint name by default).

Square of Euclidean distance of town (46, or mappable variable: roadstop_town_distance_squared)

The town used is the one associated with the station/waypoint (this is in the station/waypoint name by default).

Player/company info (47, or mappable variable: roadstop_company_info)

This has the same value as vehicle (features 0 - 3) variable 43.
The company used is the owner of the station/waypoint, not the owner of the underlying road and/or tram.

Current animation frame (49, or mappable variable: roadstop_animation_frame)

This has the same value as station (feature 4) variable 4A.

Miscellaneous road stop info (50, or mappable variable: roadstop_misc_info)

Animation frame of nearby tile (66, or mappable variable: roadstop_animation_frame_nearby_tiles)

This has the same value as station (feature 4) variable 66.

Land info of nearby tile (67, or mappable variable: roadstop_land_info_nearby_tiles)

This has the same value as industry tile (feature 9) variable 60.

Road stop of nearby tile (68, or mappable variable: roadstop_road_stop_info_nearby_tiles)

This has a similar value to station (feature 4) variable 68.

GRFID of nearby road stop tile (6A, or mappable variable: roadstop_road_stop_grfid_nearby_tiles)

This has the same value as station (feature 4) variable 6A.

Random Action 2 - Road Stops

See the Random Action 2 Specification for background information.

Road stops have 16+8 random bits. Bits 0 to 15 are a property of the station as a whole, and bits 16 to 23 are different for each tile.

Also note that none of the above triggers will actually trigger unless property 0D/roadstop_random_trigger_cargoes has at least one bit set.
Triggers 01 will be triggered for any of the cargo types set in property 0D/roadstop_random_trigger_cargoes, but trigger 02 will only be triggered if all of those cargo types have no more cargo waiting.
Triggers 04 and 08 are triggered no matter what cargo types the train transports, as long as property 0D/roadstop_random_trigger_cargoes is not zero.
Triggers 04, 08, and 10 only affect the tile on which they occur, as well as the random bits of the station, but not other tiles.

Action 3 - Road Stops

See the Action 3 Specification for background information.

Road stops have the same Action 3 cargo-type values as feature 4 (station).