Clamp Layout

A procedural layout wrapper that clamps a layout to change no more
frequently than some limiting parameter. If you underestimate how
rapidly the underlying layout changes, aliasing will occur.

1 files changed, 63 insertions, 28 deletions

diff --git a/crawl-ref/source/dgn-proclayouts.h b/crawl-ref/source/dgn-proclayouts.h
index 343e954557..5cbefe3288 100644
--- a/crawl-ref/source/dgn-proclayouts.h
+++ b/crawl-ref/source/dgn-proclayouts.h
@@ -20,7 +20,9 @@ dungeon_feature_type sanitize_feature(dungeon_feature_type feature,
 class ProceduralSample
 {
     public:
-        ProceduralSample(const coord_def _c, const dungeon_feature_type _ft, const uint32_t _cp, map_mask_type _m = MMT_NONE) :
+        ProceduralSample(const coord_def _c,
+            const dungeon_feature_type _ft,
+            const uint32_t _cp, map_mask_type _m = MMT_NONE) :
             c(_c), ft(_ft), cp(_cp), m(_m) {}
         coord_def coord() const { return c; }
         dungeon_feature_type feat() const { return ft; }
@@ -29,11 +31,12 @@ class ProceduralSample
     private:
         coord_def c;
         dungeon_feature_type ft;
-        // A lower bound estimate of when this feat can change in terms of absolute abyss depth.
-        // If you say that a feature might change by depth 1000, it will get checked at depth 1000.
-        // Then it will get pushed back into the terrain queue with the new depth estimate.
-        // If you overestimate the time between shifts, this will introduce bad behavior when a game is
-        // loaded. [bh]
+        // A lower bound estimate of when this feat can change in terms of
+        // absolute abyss depth. If you say that a feature might change by
+        // depth 1000, it will get checked at depth 1000. Then it will get
+        // pushed back into the terrain queue with the new depth estimate.
+        // If you overestimate the time between shifts, this will introduce
+        // bad behavior when a game is loaded. [bh]
         uint32_t cp;
         map_mask_type m;
 };
@@ -41,7 +44,8 @@ class ProceduralSample
 class ProceduralSamplePQCompare
 {
     public:
-        bool operator() (const ProceduralSample &lhs, const ProceduralSample &rhs)
+        bool operator() (const ProceduralSample &lhs,
+            const ProceduralSample &rhs)
         {
             return lhs.changepoint() > rhs.changepoint();
         }
@@ -50,7 +54,8 @@ class ProceduralSamplePQCompare
 class ProceduralLayout
 {
     public:
-        virtual ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const = 0;
+        virtual ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const = 0;
         virtual ~ProceduralLayout() { }
 };
 
@@ -68,7 +73,8 @@ class ColumnLayout : public ProceduralLayout
             _row_space = (rs < 0 ? cs : rs);
         }
 
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         int _col_width, _col_space, _row_width, _row_space;
 };
@@ -77,7 +83,8 @@ class DiamondLayout : public ProceduralLayout
 {
     public:
         DiamondLayout(int _w, int _s) : w(_w) , s(_s) { }
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         uint32_t w, s;
 };
@@ -86,9 +93,12 @@ class DiamondLayout : public ProceduralLayout
 class WorleyLayout : public ProceduralLayout
 {
     public:
-        WorleyLayout(uint32_t _seed, vector<const ProceduralLayout*> _layouts, const float _scale = 2.0)
-                : seed(_seed), layouts(_layouts), scale(_scale) {}
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        WorleyLayout(uint32_t _seed,
+            vector<const ProceduralLayout*> _layouts,
+            const float _scale = 2.0) :
+            seed(_seed), layouts(_layouts), scale(_scale) {}
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         const uint32_t seed;
         const vector<const ProceduralLayout*> layouts;
@@ -96,16 +106,18 @@ class WorleyLayout : public ProceduralLayout
 };
 
 // A pseudo-random layout with variable density.
-// By default, 45% of the area is wall. Densities in excess of 50% (500) are very
-// likely to create isolated bubbles. See http://en.wikipedia.org/wiki/Percolation_theory
-// for additional information.
+// By default, 45% of the area is wall. Densities in excess of 50% (500)
+// are very likely to create isolated bubbles.
+// See http://en.wikipedia.org/wiki/Percolation_theory for additional
+// information.
 // This layout is depth invariant.
 class ChaosLayout : public ProceduralLayout
 {
     public:
-        ChaosLayout(uint32_t _seed, uint32_t _density = 450)
-            : seed(_seed), baseDensity(_density) {}
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        ChaosLayout(uint32_t _seed, uint32_t _density = 450) :
+            seed(_seed), baseDensity(_density) {}
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         const uint32_t seed;
         const uint32_t baseDensity;
@@ -115,9 +127,10 @@ class ChaosLayout : public ProceduralLayout
 class RoilingChaosLayout : public ProceduralLayout
 {
     public:
-        RoilingChaosLayout(uint32_t _seed, uint32_t _density = 450)
-            : seed(_seed), density(_density) {}
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        RoilingChaosLayout(uint32_t _seed, uint32_t _density = 450) :
+            seed(_seed), density(_density) {}
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         const uint32_t seed;
         const uint32_t density;
@@ -128,14 +141,17 @@ class WastesLayout : public ProceduralLayout
 {
     public:
         WastesLayout() { };
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
 };
 
 class RiverLayout : public ProceduralLayout
 {
     public:
-        RiverLayout(uint32_t _seed, const ProceduralLayout &_layout) : seed(_seed), layout(_layout) {}
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        RiverLayout(uint32_t _seed, const ProceduralLayout &_layout) :
+            seed(_seed), layout(_layout) {}
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         const uint32_t seed;
         const ProceduralLayout &layout;
@@ -146,7 +162,8 @@ class NewAbyssLayout : public ProceduralLayout
 {
     public:
         NewAbyssLayout(uint32_t _seed) : seed(_seed) {}
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         const uint32_t seed;
 };
@@ -156,12 +173,30 @@ class NewAbyssLayout : public ProceduralLayout
 class LevelLayout : public ProceduralLayout
 {
     public:
-        LevelLayout(level_id id, uint32_t _seed, const ProceduralLayout &_layout);
-        ProceduralSample operator()(const coord_def &p, const uint32_t offset = 0) const;
+        LevelLayout(level_id id, uint32_t _seed,
+            const ProceduralLayout &_layout);
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
     private:
         feature_grid grid;
         uint32_t seed;
         const ProceduralLayout &layout;
 };
 
+// Clamps another layout so that it changes no more frequently than specified
+// by the clamp parameter. This is useful if you can't find a good analytic
+// bound on how rapidly your layout changes. If you provide a high valued clamp
+// to a fast changing layout, aliasing will occur.
+class ClampLayout : public ProceduralLayout
+{
+    public:
+        ClampLayout(const ProceduralLayout &_layout, int _clamp) :
+            layout(_layout), clamp(_clamp) {}
+        ProceduralSample operator()(const coord_def &p,
+            const uint32_t offset = 0) const;
+    private:
+        const ProceduralLayout &layout;
+        const int clamp;
+};
+
 #endif /* PROC_LAYOUTS_H */