Fixed/improved river tile detection

docs/changelog.txt

@@ -52,6 +52,8 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 - `embark-assistant`:
     - fixed bug causing crash on worlds without generated metals (as well as pruning vectors as originally intended).
     - fixed bug causing mineral matching to fail to cut off at the magma sea, reporting presence of things that aren't (like DF does currently).
+    - fixed bug causing half of the river tiles not to be recognized.
+    - added logic to detect some river tiles DF doesn't generate data for (but are definitely present).
 - `gui/autogems`: fixed error when no world is loaded
 - `gui/companion-order`:
     - fixed error when resetting group leaders

plugins/embark-assistant/matcher.cpp

@@ -2076,7 +2076,7 @@ namespace embark_assist {
         uint32_t preliminary_world_match(embark_assist::defs::world_tile_data *survey_results,
             embark_assist::defs::finders *finder,
             embark_assist::defs::match_results *match_results) {
-            //            color_ostream_proxy out(Core::getInstance().getConsole());
+//                        color_ostream_proxy out(Core::getInstance().getConsole());
             uint32_t count = 0;
             for (uint16_t i = 0; i < world->worldgen.worldgen_parms.dim_x; i++) {
                 for (uint16_t k = 0; k < world->worldgen.worldgen_parms.dim_y; k++) {

plugins/embark-assistant/survey.cpp

@@ -1043,11 +1043,11 @@ void embark_assist::survey::survey_mid_level_tile(embark_assist::defs::geo_data
             mlt->at(i).at(k).river_present = false;
             mlt->at(i).at(k).river_elevation = 100;
 
-            if (details->rivers_vertical.active[i][k] == 1) {
+            if (details->rivers_vertical.active[i][k] != 0) {
                 mlt->at(i).at(k).river_present = true;
                 mlt->at(i).at(k).river_elevation = details->rivers_vertical.elevation[i][k];
             }
-            else if (details->rivers_horizontal.active[i][k] == 1) {
+            else if (details->rivers_horizontal.active[i][k] != 0) {
                 mlt->at(i).at(k).river_present = true;
                 mlt->at(i).at(k).river_elevation = details->rivers_horizontal.elevation[i][k];
             }
@@ -1179,6 +1179,51 @@ void embark_assist::survey::survey_mid_level_tile(embark_assist::defs::geo_data
         }
     }
 
+    //  This is messy. DF has some weird logic to leave out river bends with a South and an East connection, as well
+    //  as river sources (and presumably sinks) that are to the North or the West of the connecting river.
+    //  Experiments indicate these implicit river bends inherit their River Elevation from the lower of the two
+    //  "parents", and it's assumed river sources and sinks similarly inherit it from their sole "parent".
+    //  Two issues are known:
+    //  - Lake and Ocean tiles may be marked as having a river when DF doesn't. However, DF does allow for rivers to
+    //    exist in Ocean/Lake tiles, as well as sources/sinks.
+    //  - DF generates rivers on/under glaciers, but does not display them (as they're frozen), nor are their names
+    //    displayed.
+    //
+    for (uint8_t i = 1; i < 16; i++) {
+        for (uint8_t k = 0; k < 15; k++) {
+            if (details->rivers_horizontal.active[i][k] != 0 &&
+                details->rivers_vertical.active[i - 1][k + 1] != 0 &&
+                !mlt->at(i - 1).at(k).river_present) {  //  Probably never true
+                mlt->at(i - 1).at(k).river_present = true;
+                mlt->at(i - 1).at(k).river_elevation = mlt->at(i).at(k).river_elevation;
+
+                if (mlt->at(i - 1).at(k).river_elevation > mlt->at(i - 1).at(k + 1).river_elevation) {
+                    mlt->at(i - 1).at(k).river_elevation = mlt->at(i - 1).at(k + 1).river_elevation;
+                }
+            }
+        }
+    }
+
+    for (uint8_t i = 0; i < 16; i++) {
+        for (uint8_t k = 1; k < 16; k++) {
+            if (details->rivers_vertical.active[i][k] != 0 &&
+                !mlt->at(i).at(k - 1).river_present) {
+                mlt->at(i).at(k - 1).river_present = true;
+                mlt->at(i).at(k - 1).river_elevation = mlt->at(i).at(k).river_elevation;
+            }
+        }
+    }
+            
+    for (uint8_t i = 1; i < 16; i++) {
+        for (uint8_t k = 0; k < 16; k++) {
+            if (details->rivers_horizontal.active[i][k] != 0 &&
+                !mlt->at(i - 1).at(k).river_present) {
+                mlt->at(i - 1).at(k).river_present = true;
+                mlt->at(i - 1).at(k).river_elevation = mlt->at(i).at(k).river_elevation;
+            }
+        }
+    }
+
     survey_results->at(x).at(y).aquifer_count = 0;
     survey_results->at(x).at(y).clay_count = 0;
     survey_results->at(x).at(y).sand_count = 0;