Add wave tiles to smoothen the transition between shallow water and floor.

Currently only applies to Shoals, partly because the relevant base tiles are
only used in the Shoals, partly because it's experimental. The checks needed
for adjacent water tiles increase the drawing time, but I'm not sure by how
much, seeing how in my test runs I only measured the seconds used for &O and
came up with no noticeable difference. Still might increase lags on computers
already prone to slow tiles, in which case we'll need to revert this change.

Making the dungeon look less "gridlike" greatly improves the graphics and
makes me want to extend the concept to floor/floor transitions, but it could
potentially harm the interface. Not sure where to draw the line, and in any
case the lag appears to be the more imminent problem.

I've also played around with also adding waves for the shallow/deep water
transitions but this would require special behaviour also for the water masks
used for monsters and items, which is not a problem for floor tiles.

10 files changed, 83 insertions, 0 deletions

diff --git a/crawl-ref/source/rltiles/dc-dngn.txt b/crawl-ref/source/rltiles/dc-dngn.txt
index f306cfd048..ef8e062e57 100644
--- a/crawl-ref/source/rltiles/dc-dngn.txt
+++ b/crawl-ref/source/rltiles/dc-dngn.txt
@@ -994,6 +994,18 @@ dngn_shoals_shallow_water_disturbance1 SHOALS_SHALLOW_WATER_DISTURBANCE
 dngn_shoals_shallow_water_disturbance2
 dngn_shoals_shallow_water_disturbance3
 
+# corner waves (diagonals)
+shallow_water_wave_corner_NE WAVE_CORNER_NE
+shallow_water_wave_corner_NW WAVE_CORNER_NW
+shallow_water_wave_corner_SE WAVE_CORNER_SE
+shallow_water_wave_corner_SW WAVE_CORNER_SW
+
+# orthogonal waves
+shallow_water_wave_N WAVE_N
+shallow_water_wave_S WAVE_S
+shallow_water_wave_E WAVE_E
+shallow_water_wave_W WAVE_W
+
 %sdir dc-dngn/gateways
 dngn_entrance DNGN_UNSEEN_ENTRANCE
 %rim 1
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_E.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_E.png
new file mode 100644
index 0000000000..d0d4a5eb24
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_E.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_N.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_N.png
new file mode 100644
index 0000000000..75d75529c3
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_N.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_S.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_S.png
new file mode 100644
index 0000000000..e043b1f083
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_S.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_W.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_W.png
new file mode 100644
index 0000000000..8cdb9890ec
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_W.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NE.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NE.png
new file mode 100644
index 0000000000..ba4bd301a5
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NE.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NW.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NW.png
new file mode 100644
index 0000000000..e86b45a553
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_NW.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SE.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SE.png
new file mode 100644
index 0000000000..3f1db4464e
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SE.png
diff --git a/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SW.png b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SW.png
new file mode 100644
index 0000000000..a187598d4c
--- /dev/null
+++ b/crawl-ref/source/rltiles/dc-dngn/water/shallow_water_wave_corner_SW.png
diff --git a/crawl-ref/source/tilereg.cc b/crawl-ref/source/tilereg.cc
index 65383f46b4..01552659d8 100644
--- a/crawl-ref/source/tilereg.cc
+++ b/crawl-ref/source/tilereg.cc
@@ -12,6 +12,7 @@
 #include "cio.h"
 #include "cloud.h"
 #include "coord.h"
+#include "coordit.h"
 #include "debug.h"
 #include "describe.h"
 #include "directn.h"
@@ -303,6 +304,76 @@ void DungeonRegion::pack_background(unsigned int bg, int x, int y)
             m_buf_dngn.add(TILE_BLOOD + offset, x, y);
         }
 
+        if (player_in_branch(BRANCH_SHOALS))
+        {
+            // Add wave tiles on floor adjacent to shallow water.
+            const coord_def pos = coord_def(x + m_cx_to_gx, y + m_cy_to_gy);
+            const dungeon_feature_type feat = env.map_knowledge(pos).feat();
+            if (feat == DNGN_FLOOR || feat == DNGN_UNDISCOVERED_TRAP)
+            {
+                const coord_def pos = coord_def(x + m_cx_to_gx, y + m_cy_to_gy);
+                bool north = false, south = false, east = false, west = false;
+                bool ne = false, nw = false, se = false, sw = false;
+                for (radius_iterator ri(pos, 1, true, false, true); ri; ++ri)
+                {
+                    if (env.map_knowledge(*ri).feat() != DNGN_SHALLOW_WATER)
+                        continue;
+
+                    if (!is_terrain_seen(*ri) && !is_terrain_mapped(*ri))
+                        continue;
+
+                    if (ri->x == pos.x) // orthogonals
+                    {
+                        if (ri->y < pos.y)
+                            north = true;
+                        else
+                            south = true;
+                    }
+                    else if (ri->y == pos.y)
+                    {
+                        if (ri->x < pos.x)
+                            west = true;
+                        else
+                            east = true;
+                    }
+                    else // diagonals
+                    {
+                        if (ri->x < pos.x)
+                        {
+                            if (ri->y < pos.y)
+                                nw = true;
+                            else
+                                sw = true;
+                        }
+                        else
+                        {
+                            if (ri->y < pos.y)
+                                ne = true;
+                            else
+                                se = true;
+                        }
+                    }
+                }
+
+                if (north)
+                    m_buf_dngn.add(TILE_WAVE_N, x, y);
+                if (south)
+                    m_buf_dngn.add(TILE_WAVE_S, x, y);
+                if (east)
+                    m_buf_dngn.add(TILE_WAVE_E, x, y);
+                if (west)
+                    m_buf_dngn.add(TILE_WAVE_W, x, y);
+                if (ne && !north && !east)
+                    m_buf_dngn.add(TILE_WAVE_CORNER_NE, x, y);
+                if (nw && !north && !west)
+                    m_buf_dngn.add(TILE_WAVE_CORNER_NW, x, y);
+                if (se && !south && !east)
+                    m_buf_dngn.add(TILE_WAVE_CORNER_SE, x, y);
+                if (sw && !south && !west)
+                    m_buf_dngn.add(TILE_WAVE_CORNER_SW, x, y);
+            }
+        }
+
         if (bg & TILE_FLAG_HALO)
             m_buf_dngn.add(TILE_HALO, x, y);