Implement extended NewGRF variable parameter support

docs/newgrf-additions.html

@@ -466,7 +466,7 @@
 	<br />
 	<h3 id="variable-mapping">Action 14 - Variable Mapping for Variational Action 2</h3>
 	<p>See <a href="https://newgrf-specs.tt-wiki.net/wiki/Action14">Action 14 Specification</a> and <a href="https://newgrf-specs.tt-wiki.net/wiki/VariationalAction2">Variational Action 2 Specification</a> for background information.</p>
-	<p>The variable mapping mechanism has the feature name: <font face="monospace">variable_mapping</font>, this document describes version 1.</p>
+	<p>The variable mapping mechanism has the feature name: <font face="monospace">variable_mapping</font>, this document describes version 1 (and where indicated, version 2).</p>
 	<p>Unlike property mappings, it is not necessary to perform a feature test or check a mapping success variable before using a mapped variable.</p>
 	<p>Remapped variables are accessed by reading from variable 0x11 using a varadjust shift-num and and-mask which exactly matches that specified in the variable mapping.<br />
 	In the absence of any successful variable mapping, variable 0x11 has all bits set to 0 and attempting to read from it with any shift-num and and-mask value
@@ -474,6 +474,9 @@
 	<p>Reading a mapped variable on a version of OpenTTD which does not support this variable mapping mechanism or which does not support the requested variable, returns a value of 0.</p>
 	<p>If more than one variable mapping is made for the same combination of feature ID, shift-num and and-mask, it is implementation-defined which mapping is used.<br />
 	Each variable mapping SHOULD use a unique combination of feature ID, shift-num and and-mask.</p>
+	<p>From version 2 of the <font face="monospace">variable_mapping</font> feature name, variable remapping can also be used with variable 0x7B.<br />
+	In this case the parameter of variable 0x7B should be set to 0x11, and the shift and mask fields set the same way in the direct 0x11 variable case.<br />
+	The "VPRM" parameter field is ignored, and the parameter used is the accumulator of the previous adjust part in the usual way for variable 0x7B.</p>
 	<h4 id="A2VM">Variable Mapping: C "A2VM"</h4>
 	<p>Each A2VM chunk (type C) describes an individual variable mapping.<br />
 	Sub-chunks within each A2VM chunk may appear in any order, however each sub-chunk SHOULD only appear ONCE within an individual A2VM chunk.</p>
@@ -500,6 +503,10 @@
 	If this is not specified, a value of 0 is assumed.</p>
 	<h4 id="A2VM-SETT">Success Indicator Global Variable 0x8D Bit: C "A2VM" -> B "SETT"</h4>
 	<p>This behaves identically to the <a href="#A0PM-SETT">C "A0PM" -> B "SETT"</a> case, above</p>
+	<h4 id="A2VM-VPRM">Replacement parameter: C "A2VM" -> B "VPRM"</h4>
+	<p>Within an A2VM chunk, the VPRM binary (type B) field contains the Variational Action 2 parameter value (as in 60+X variables) to use on the mapped variable. This is 4 bytes.<br />
+	If this is not specified, a value of 0 is assumed.<br />
+	Support for this field is indicated by the feature name <font face="monospace">variable_mapping</font>, version 2.</p>
 	<h4 id="A2VM-example">Example NFO:</h4>
 	<pre>
 // Map station variable "sample_station_variable" with a shift-num of 4 and an and-mask of 0xFF, to reads of variable 0x11 with a shift-num of 1 and an and-mask of 0x2, and set bit 4 of global variable 0x8D if successful

src/newgrf.cpp

@@ -5414,6 +5414,16 @@ static void NewSpriteGroup(ByteReader *buf)
 							adjust.variable = remap.id;
 							adjust.shift_num = remap.output_shift;
 							adjust.and_mask = remap.output_mask;
+							adjust.parameter = remap.output_param;
+							break;
+						}
+					}
+				} else if (adjust.variable == 0x7B && adjust.parameter == 0x11) {
+					for (const GRFVariableMapEntry &remap : _cur.grffile->grf_variable_remaps) {
+						if (remap.feature == feature && remap.input_shift == adjust.shift_num && remap.input_mask == adjust.and_mask) {
+							adjust.parameter = remap.id;
+							adjust.shift_num = remap.output_shift;
+							adjust.and_mask = remap.output_mask;
 							break;
 						}
 					}
@@ -8799,6 +8809,7 @@ struct GRFPropertyMapAction {
 	uint8 output_shift;
 	uint input_mask;
 	uint output_mask;
+	uint output_param;
 
 	void Reset(const char *tag, const char *desc)
 	{
@@ -8814,6 +8825,7 @@ struct GRFPropertyMapAction {
 		this->output_shift = 0;
 		this->input_mask = 0;
 		this->output_mask = 0;
+		this->output_param = 0;
 	}
 
 	void ExecuteFeatureIDRemapping()
@@ -8930,7 +8942,7 @@ struct GRFPropertyMapAction {
 		extern const GRFVariableMapDefinition _grf_action2_remappable_variables[];
 		for (const GRFVariableMapDefinition *info = _grf_action2_remappable_variables; info->name != nullptr; info++) {
 			if (info->feature == this->feature && strcmp(info->name, str) == 0) {
-				_cur.grffile->grf_variable_remaps.push_back({ (uint16)info->id, (uint8)this->feature, this->input_shift, this->output_shift, this->input_mask, this->output_mask });
+				_cur.grffile->grf_variable_remaps.push_back({ (uint16)info->id, (uint8)this->feature, this->input_shift, this->output_shift, this->input_mask, this->output_mask, this->output_param });
 				success = true;
 				break;
 			}
@@ -9162,8 +9174,7 @@ static bool ChangePropertyRemapSetOutputParam(size_t len, ByteReader *buf)
 		grfmsg(2, "Action 14 %s mapping: expected 4 bytes for '%s'->'VPRM' but got " PRINTF_SIZE ", ignoring this field", action.descriptor, action.tag_name, len);
 		buf->Skip(len);
 	} else {
-		buf->ReadDWord();
+		action.output_param = buf->ReadDWord();
-		/* This is not implemented yet, so just do nothing, but still validate that the format is correct */
 	}
 	return true;
 }

src/newgrf.h

@@ -211,6 +211,7 @@ struct GRFVariableMapEntry {
 	uint8 output_shift = 0;
 	uint32 input_mask = 0;
 	uint32 output_mask = 0;
+	uint32 output_param = 0;
 };
 
 /** The type of action 5 type. */

src/newgrf_extension.cpp

@@ -18,7 +18,7 @@
 extern const GRFFeatureInfo _grf_feature_list[] = {
 	GRFFeatureInfo("feature_test", 1),
 	GRFFeatureInfo("property_mapping", 1),
-	GRFFeatureInfo("variable_mapping", 1),
+	GRFFeatureInfo("variable_mapping", 2),
 	GRFFeatureInfo("feature_id_mapping", 1),
 	GRFFeatureInfo("action5_type_id_mapping", 1),
 	GRFFeatureInfo("action0_station_prop1B", 1),

src/newgrf_spritegroup.cpp

@@ -595,7 +595,7 @@ void SpriteGroupDumper::DumpSpriteGroup(const SpriteGroup *sg, int padding, uint
 						}
 					}
 				}
-				if (adjust.variable >= 0x60 && adjust.variable <= 0x7F) p += seprintf(p, lastof(this->buffer), " (parameter: %X)", adjust.parameter);
+				if ((adjust.variable >= 0x60 && adjust.variable <= 0x7F) || adjust.parameter != 0) p += seprintf(p, lastof(this->buffer), " (parameter: %X)", adjust.parameter);
 				p += seprintf(p, lastof(this->buffer), ", shift: %X, and: %X", adjust.shift_num, adjust.and_mask);
 				switch (adjust.type) {
 					case DSGA_TYPE_DIV: p += seprintf(p, lastof(this->buffer), ", add: %X, div: %X", adjust.add_val, adjust.divmod_val); break;