This document describes non-standard additions to the Official OpenTTD NML Specifications which are present in this patchpack and the associated NML fork.
These additions MAY also be present in other patchpacks. They MAY be removed or moved in future, if necessary.
Not all standard NewGRF features are supported by NML, consequently not all non-standard additions to the specifications are supported by this patchpack's associated NML fork, or are listed in this document.
See the associated non-NML document for more details.
All of the non-standard features listed below will automatically emit suitable feature tests, conditionals, etc. such that NewGRFs which use these features will work correctly on OpenTTD versions which do not support these features, including standard trunk OpenTTD and older/other patchpack versions.
| Property | Value range | Comment | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| enable_programmable_pre_signals | 0 or 1 |
Enable programmable pre-signal graphics in railtype signals. Programmable pre-signals have a signal type (getbits(extra_callback_info2, 16, 8)) of 6. |
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| enable_restricted_signals | 0 or 1 |
Enable restricted signal flag in railtype signals. When enabled, bit 24 of variable extra_callback_info2 is set if the signal is restricted (has a routing restriction program attached). When enabled, the "Show restricted electric signals using default graphics" client setting and signal post recolouring is not applied. This flag must only be set if a different sprite is returned when bit 24 of extra_callback_info2 is set. |
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| enable_signal_recolour | 0 or 1 |
Enable recolouring of graphics in railtype signals. When enabled, in addition to returning a sprite, register 0x100 may be set to the following using STORE_TEMP:
If recolouring is not optional, the feature name: action0_railtype_recolour should be checked using the extended_feature_test function and if necessary a suitable fallback used or error message shown. If the OpenTTD version does not support this property/feature, then the property would ordinarily be ignored/skipped and no recolouring would be done. |
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| extra_aspects | 0 - 6 |
The value is the number of additional signal aspects to use (e.g. 4-aspect signalling should use a value of 2). When set, the lowest byte of extra_callback_info2 (signal state) may have the given number of additional values starting from 02:
The provided value is currently clamped to be within the range 0 - 6 (inclusive). N.B. Realistic braking must be enabled for additional signal aspects to be used |
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| disable_realistic_braking | 0 or 1 | When this property is set realistic braking is disabled for trains of this railtype even when realistic braking is otherwise in effect. |
| Property | Value range | Comment |
|---|---|---|
| roadtype_extra_flags | bitmask(ROADTYPE_EXTRA_FLAG_XXX, ...) |
|
| Property | Value range | Comment |
|---|---|---|
| tramtype_extra_flags | bitmask(TRAMTYPE_EXTRA_FLAG_XXX, ...) |
|
| Type | Number of sprites | Comment | ||||||
|---|---|---|---|---|---|---|---|---|
| PROGRAMMABLE_PRE_SIGNAL | 32 |
Programmable pre-signals
Signal graphics come in groups of 16. These groups contain sprites in the same order as sprites 1275-1290 in trg1[r].grf and Action 5 type 4 (signals); red, then green, for each of: SW-facing, NE-facing, NW-facing, SE-facing, E-facing, W-facing, S-facing, N-facing.
|
This feature allows signal sprites to be specified using switches in a very similar manner to railtype signals in
item (FEAT_RAILTYPES) { graphics { signals: ... } } blocks.
However this applies to all signals, not only those of a particular rail type.
Railtype signal graphics have a higher priority than general signal graphics as set here.
Variables: extra_callback_info1, extra_callback_info2, and terrain_type
are the same as for railtype signals.
This feature is not supported by standard OpenTTD or by standard NML.
If the use of this feature is not optional, the feature name: action3_signals_custom_signal_sprites should be checked using the
extended_feature_test function
and if necessary a suitable fallback used or error message shown.
An item (FEAT_SIGNALS, custom_signals, 0) { } block should be used to define properties and graphics.
The graphics block should contain a single default switch.
| Property | Value range | Comment | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| enable_programmable_pre_signals | 0 or 1 |
Enable programmable pre-signal graphics. Programmable pre-signals have a signal type (getbits(extra_callback_info2, 16, 8)) of 6. |
||||||||||||
| enable_restricted_signals | 0 or 1 |
Enable restricted signal flag. When enabled, bit 24 of variable extra_callback_info2 is set if the signal is restricted (has a routing restriction program attached). When enabled, the "Show restricted electric signals using default graphics" client setting and signal post recolouring is not applied. This flag must only be set if a different sprite is returned when bit 24 of extra_callback_info2 is set. |
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| enable_signal_recolour | 0 or 1 |
Enable recolouring of graphics When enabled, in addition to returning a sprite, register 0x100 may be set to the following using STORE_TEMP:
|
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| extra_aspects | 0 - 6 |
The value is the number of additional signal aspects to use (e.g. 4-aspect signalling should use a value of 2). When set, the lowest byte of extra_callback_info2 (signal state) may have the given number of additional values starting from 02:
The provided value is currently clamped to be within the range 0 - 6 (inclusive). N.B. Realistic braking must be enabled for additional signal aspects to be used |
Custom signal sprites example:
grf {
...
}
if (!extended_feature_test("action3_signals_custom_signal_sprites")) {
error(FATAL, string(STR_UNSUPPORTED_VERSION));
}
switch (FEAT_SIGNALS, SELF, switch_signals, ...) {
...
}
item (FEAT_SIGNALS, custom_signals, 0) {
property {
enable_signal_recolour: 1;
}
graphics {
switch_signals;
}
}