Add Action 5 support for programmable signals graphics

docs/newgrf-additions.html

@@ -249,5 +249,15 @@
 -1  sprites/sample.png 546 8 09 23 33 -26 0
 -1  sprites/sample.png 594 8 09 23 33 -5 0
 	</pre>
+	<h4>Programmable signal graphics (mappable type: programmable_signals)</h4>
+	<p>Signal graphics come in groups of 16. These groups contain sprites in the same order as sprites 1275-1290 in trg1[r].grf and <a href="https://newgrf-specs.tt-wiki.net/wiki/Action5#04_Signal_graphics.">Action 5 type 4 (signals)</a>;
+		red, then green, for each of: SW-facing, NE-facing, NW-facing, SE-facing, E-facing, W-facing, S-facing, N-facing.
+	<table>
+		<tr><th>Group</th><th>Contents</th></tr>
+		<tr><td>0</td><td>Semaphore programmable signals</td></tr>
+		<tr><td>1</td><td>Lighted programmable signals</td></tr>
+	</table>
+	</p>
+	<p>This is indicated by the feature name: <font face="monospace">action5_programmable_signals</font>, version 1</p>
 </body>
 </html>

src/newgrf.cpp

@@ -7992,6 +7992,7 @@ static const GRFFeatureInfo _grf_feature_list[] = {
 	GRFFeatureInfo("more_bridge_types", 1),
 	GRFFeatureInfo("action0_bridge_prop14", 1),
 	GRFFeatureInfo("action0_bridge_pillar_flags", 1),
+	GRFFeatureInfo("action5_programmable_signals", 1),
 	GRFFeatureInfo(),
 };
 
@@ -8112,6 +8113,7 @@ static const GRFPropertyMapDefinition _grf_action0_remappable_properties[] = {
 
 /** Action14 Action5 remappable type list */
 static const Action5TypeRemapDefinition _grf_action5_remappable_types[] = {
+	Action5TypeRemapDefinition("programmable_signals", A5BLOCK_ALLOW_OFFSET, SPR_PROGSIGNAL_BASE, 1, 32, "Programmable signal graphics"),
 	Action5TypeRemapDefinition(),
 };