3 files changed, 216 insertions, 114 deletions

@@ -21,14 +21,13 @@
 #define SPEED_UP_AUTOSCROLLERS 0x408
 
 /* ------- Temp ------- */
+#include "Panel.h"
+#include <sstream>
+
 #define TMP1 0x501
 #define TMP2 0x502
-#define TMP3 0x503
-#define TMP4 0x504
 
-#include "Panel.h"
-// int panel = 0x33D4; // Tutorial vault
-int panel = 0x0005D; // Outside Tutorial Dots Tutorial 1
+HWND g_panelId;
 Puzzle g_puzzle;
 /* ------- Temp ------- */
 
@@ -132,10 +131,28 @@ LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
                 CheckDlgButton(hwnd, SPEED_UP_AUTOSCROLLERS, !IsDlgButtonChecked(hwnd, SPEED_UP_AUTOSCROLLERS));
                 break;
             case TMP1:
-                g_puzzle = PuzzleSerializer(g_witnessProc).ReadPuzzle(panel);
+                {
+                    std::wstring text(128, L'\0');
+                    int length = GetWindowText(g_panelId, text.data(), static_cast<int>(text.size()));
+                    text.resize(length);
+                    std::wstringstream s;
+                    int panelId;
+                    s << text;
+                    s >> std::hex >> panelId;
+                    g_puzzle = PuzzleSerializer(g_witnessProc).ReadPuzzle(panelId);
+                }
                 break;
             case TMP2:
-                PuzzleSerializer(g_witnessProc).WritePuzzle(g_puzzle, panel);
+                {
+                    std::wstring text(128, L'\0');
+                    int length = GetWindowText(g_panelId, text.data(), static_cast<int>(text.size()));
+                    text.resize(length);
+                    std::wstringstream s;
+                    int panelId;
+                    s << text;
+                    s >> std::hex >> panelId;
+                    PuzzleSerializer(g_witnessProc).WritePuzzle(g_puzzle, panelId);
+                }
                 break;
         }
     }
@@ -219,9 +236,9 @@ int APIENTRY wWinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance
     CreateCheckbox(10, 340, SPEED_UP_AUTOSCROLLERS);
     CreateLabel(30, 340, 205, L"Speed up various autoscrollers");
 
-    CreateButton(200, 100, 100, L"Read", TMP1);
-    CreateButton(200, 130, 100, L"Write", TMP2);
-    CreateButton(200, 190, 100, L"Dump", TMP4);
+    g_panelId = CreateText(200, 100, 100, L"A3B2");
+    CreateButton(200, 130, 100, L"Read", TMP1);
+    CreateButton(200, 160, 100, L"Write", TMP2);
 
     g_witnessProc->StartHeartbeat(g_hwnd);
 
@@ -10,6 +10,7 @@ Puzzle PuzzleSerializer::ReadPuzzle(int id) {
     Puzzle p;
     p.width = 2 * _memory->ReadPanelData<int>(id, GRID_SIZE_X, 1)[0] - 1;
     p.height = 2 * _memory->ReadPanelData<int>(id, GRID_SIZE_Y, 1)[0] - 1;
+    if (p.width < 0 || p.height < 0) return p; // @Error: Grid size should be always positive? Looks like the starting panels break this rule, though.
     p.grid.resize(p.width);
         for (auto& row : p.grid) row.resize(p.height);
 
@@ -22,78 +23,87 @@ Puzzle PuzzleSerializer::ReadPuzzle(int id) {
 void PuzzleSerializer::ReadIntersections(Puzzle& p, int id) {
         int numIntersections = _memory->ReadPanelData<int>(id, NUM_DOTS, 1)[0];
         std::vector<int> intersectionFlags = _memory->ReadArray<int>(id, DOT_FLAGS, numIntersections);
+        int numConnections = _memory->ReadPanelData<int>(id, NUM_CONNECTIONS, 1)[0];
+        std::vector<int> connections_a = _memory->ReadArray<int>(id, DOT_CONNECTION_A, numConnections);
+        std::vector<int> connections_b = _memory->ReadArray<int>(id, DOT_CONNECTION_B, numConnections);
+        std::vector<float> intersectionLocations = _memory->ReadArray<float>(id, DOT_POSITIONS, numIntersections*2);
 
+    // @Cleanup: Change defaults?
+    for (int x=0; x<p.width; x++) {
+        for (int y=0; y<p.height; y++) {
+            if (x%2 == y%2) continue;
+            p.grid[x][y].gap = Cell::Gap::FULL;
+        }
+    }
+
+    for (int j=0; j<numIntersections; j++) {
+                float x1 = intersectionLocations[2*connections_a[j]];
+                float y1 = intersectionLocations[2*connections_a[j]+1];
+                float x2 = intersectionLocations[2*connections_b[j]];
+                float y2 = intersectionLocations[2*connections_b[j]+1];
+        auto [x, y] = loc_to_xy(p, connections_a[j]);
+        
+                         if (x1 < x2) x++;
+                else if (x1 > x2) x--;
+                else if (y1 < y2) y--;
+                else if (y1 > y2) y++;
+        p.grid[x][y].gap = Cell::Gap::NONE;
+    }
+
+    // This iterates bottom-top, left-right
         int i = 0;
         for (;; i++) {
+        int flags = intersectionFlags[i];
                 auto [x, y] = loc_to_xy(p, i);
                 if (y < 0) break;
-                if (intersectionFlags[i] & Flags::IS_STARTPOINT) {
+                if (flags & Flags::IS_STARTPOINT) {
             p.grid[x][y].start = true;
                 }
-        p.grid[x][y].dot = FlagsToDot(intersectionFlags[i]);
+        p.grid[x][y].dot = FlagsToDot(flags);
+        if (flags & Flags::IS_FULL_GAP) {
+            p.grid[x][y].gap = Cell::Gap::FULL;
+        }
         }
 
-        int numConnections = _memory->ReadPanelData<int>(id, NUM_CONNECTIONS, 1)[0];
-        std::vector<int> connections_a = _memory->ReadArray<int>(id, DOT_CONNECTION_A, numConnections);
-        std::vector<int> connections_b = _memory->ReadArray<int>(id, DOT_CONNECTION_B, numConnections);
-        std::vector<float> intersections = _memory->ReadArray<float>(id, DOT_POSITIONS, numIntersections*2);
-
         // Iterate the remaining intersections (endpoints, dots, gaps)
         for (; i < numIntersections; i++) {
+        int location = FindConnection(i, connections_a, connections_b);
+                if (location == -1) continue; // @Error: Unable to find connection point
+        // (x1, y1) location of this intersection
+        // (x2, y2) location of the connected intersection
+                float x1 = intersectionLocations[2*i];
+                float y1 = intersectionLocations[2*i+1];
+                float x2 = intersectionLocations[2*location];
+                float y2 = intersectionLocations[2*location+1];
+        auto [x, y] = loc_to_xy(p, location);
+
                 if (intersectionFlags[i] & Flags::IS_ENDPOINT) {
-                        for (int j=0; j<numConnections; j++) {
-                                int location = 0;
-                                if (connections_a[j] == i) location = connections_b[j];
-                                if (connections_b[j] == i) location = connections_a[j];
-                                if (location != 0) {
-                                        auto [x, y] = loc_to_xy(p, location);
-                                        if (intersections[2*i] < intersections[2*location]) { // Our (i) x coordinate is less than the target's (location)
-                        p.grid[x][y].end = Cell::Dir::LEFT;
-                                        } else if (intersections[2*i] > intersections[2*location]) {
-                        p.grid[x][y].end = Cell::Dir::RIGHT;
-                                        } else if (intersections[2*i + 1] > intersections[2*location + 1]) { // y coordinate is 0 (bottom) 1 (top), so this check is reversed.
-                        p.grid[x][y].end = Cell::Dir::UP;
-                                        } else {
-                        p.grid[x][y].end = Cell::Dir::DOWN;
-                                        }
-                                        break;
-                                }
-                        }
+            // Our x coordinate is less than the target's
+                             if (x1 < x2) p.grid[x][y].end = Cell::Dir::LEFT;
+                        else if (x1 > x2) p.grid[x][y].end = Cell::Dir::RIGHT;
+            // Note that Y coordinates are reversed: 0.0 (bottom) 1.0 (top)
+                        else if (y1 < y2) p.grid[x][y].end = Cell::Dir::DOWN;
+            else if (y1 > y2) p.grid[x][y].end = Cell::Dir::UP;
                 } else if (intersectionFlags[i] & Flags::HAS_DOT) {
-                        for (int j=0; j<numConnections; j++) {
-                                int location = 0;
-                                if (connections_a[j] == i) location = connections_b[j];
-                                if (connections_b[j] == i) location = connections_a[j];
-                                if (location != 0) {
-                                        auto [x, y] = loc_to_xy(p, location);
-                                        float x1 = intersections[2*i];
-                                        float y1 = intersections[2*i+1];
-                                        float x2 = intersections[2*location];
-                                        float y2 = intersections[2*location+1];
-                                        if (intersections[2*i] < intersections[2*location]) {
-                                                // Our (i) x coordinate is less than the target's (location), so we are to the left
-                                                x--;
-                                        } else if (intersections[2*i] > intersections[2*location]) { // To the right
-                                                x++;
-                                        } else if (intersections[2*i + 1] > intersections[2*location + 1]) {
-                                                // y coordinate is 0 (bottom) 1 (top), so this check is reversed. We are above the target (location)
-                                                y--;
-                                        } else { // Beleow the target
-                                                y++;
-                                        }
-
-                    p.grid[x][y].dot = FlagsToDot(intersectionFlags[i]);
-                                        break;
-                                }
-                        }
-                }
+                             if (x1 < x2) x--;
+                        else if (x1 > x2) x++;
+                        else if (y1 < y2) y++;
+                        else if (y1 > y2) y--;
+            p.grid[x][y].dot = FlagsToDot(intersectionFlags[i]);
+        } else if (intersectionFlags[i] & Flags::HAS_NO_CONN) {
+                             if (x1 < x2) x--;
+                        else if (x1 > x2) x++;
+                        else if (y1 < y2) y++;
+                        else if (y1 > y2) y--;
+            p.grid[x][y].gap = Cell::Gap::BREAK;
+        }
         }       
 }
 
 void PuzzleSerializer::ReadDecorations(Puzzle& p, int id) {
         int numDecorations = _memory->ReadPanelData<int>(id, NUM_DECORATIONS, 1)[0];
         std::vector<int> decorations = _memory->ReadArray<int>(id, DECORATIONS, numDecorations);
-    if (numDecorations != decorations.size()) return; // @Error!
+    if (numDecorations > 0) p.hasDecorations = true;
 
         for (int i=0; i<numDecorations; i++) {
                 auto [x, y] = dloc_to_xy(p, i);
@@ -119,13 +129,13 @@ void PuzzleSerializer::WritePuzzle(const Puzzle& p, int id) {
         _memory->WritePanelData<int>(id, GRID_SIZE_Y, {(p.height + 1)/2});
 
         WriteIntersections(p, id);
-        WriteDecorations(p, id);
+    if (p.hasDecorations) WriteDecorations(p, id);
 
         _memory->WritePanelData<int>(id, NEEDS_REDRAW, {1});
 }
 
 void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
-        std::vector<float> intersections;
+        std::vector<float> intersectionLocations;
         std::vector<int> intersectionFlags;
         std::vector<int> connections_a;
         std::vector<int> connections_b;
@@ -134,30 +144,56 @@ void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
         float max = 0.9f;
         float width_interval = (max - min) / (p.width/2);
         float height_interval = (max - min) / (p.height/2);
+    float horiz_gap_size = width_interval / 2;
+    float verti_gap_size = height_interval / 2;
 
-        // @Cleanup: If I write directly to locations, then I can remove this gross loop iterator.
+    // TODO: Compute HAS_NO_CONN / HAS_HORIZ_CONN / HAS_VERTI_CONN in this loop.
+        // @Cleanup: If I write directly to locations, then I can simplify this gross loop iterator.
+    // int numIntersections = (p.width / 2 + 1) * (p.height / 2 + 1);
+    // Grided intersections
         for (int y=p.height-1; y>=0; y-=2) {
                 for (int x=0; x<p.width; x+=2) {
-                        intersections.push_back(static_cast<float>(min + (x/2) * width_interval));
-                        intersections.push_back(static_cast<float>(max - (y/2) * height_interval));
+                        intersectionLocations.push_back(min + (x/2) * width_interval);
+                        intersectionLocations.push_back(max - (y/2) * height_interval);
                         int flags = 0;
             if (p.grid[x][y].start) {
                 flags |= Flags::IS_STARTPOINT;
             }
+            if (p.grid[x][y].gap == Cell::Gap::FULL) {
+                flags |= Flags::IS_FULL_GAP;
+            }
+            switch (p.grid[x][y].dot) {
+                case Cell::Dot::BLACK:
+                    flags |= Flags::HAS_DOT;
+                    break;
+                case Cell::Dot::BLUE:
+                    flags |= Flags::HAS_DOT | Flags::DOT_IS_BLUE;
+                    break;
+                case Cell::Dot::YELLOW:
+                    flags |= Flags::HAS_DOT | Flags::DOT_IS_ORANGE;
+                    break;
+                case Cell::Dot::INVISIBLE:
+                    flags |= Flags::HAS_DOT | Flags::DOT_IS_INVISIBLE;
+                    break;
+            }
+
                         intersectionFlags.push_back(flags);
 
-                        // Create connections for this intersection -- always write low -> high
-                        if (y > 0) {
+                        // Create connections for this intersection -- always write the smaller value into a, the larger into b
+            // Bottom connection
+                        if (y > 0 && p.grid[x][y-1].gap == Cell::Gap::NONE) {
                                 connections_a.push_back(xy_to_loc(p, x, y-2));
                                 connections_b.push_back(xy_to_loc(p, x, y));
                         }
-                        if (x > 0) {
+            // Left connection
+                        if (x > 0 && p.grid[x-1][y].gap == Cell::Gap::NONE) {
                                 connections_a.push_back(xy_to_loc(p, x-2, y));
                                 connections_b.push_back(xy_to_loc(p, x, y));
                         }
                 }
         }
 
+    // Endpoints
     for (int x=0; x<p.width; x++) {
         for (int y=0; y<p.height; y++) {
             if (p.grid[x][y].end == Cell::Dir::NONE) continue;
@@ -180,8 +216,8 @@ void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
                                 yPos -= .05f;
                     break;
             }
-                    intersections.push_back(xPos);
-                    intersections.push_back(yPos);
+                    intersectionLocations.push_back(xPos);
+                    intersectionLocations.push_back(yPos);
                     intersectionFlags.push_back(Flags::IS_ENDPOINT);
         }
     }
@@ -190,7 +226,28 @@ void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
     for (int x=0; x<p.width; x++) {
         for (int y=0; y<p.height; y++) {
                         if (p.grid[x][y].dot == Cell::Dot::NONE) continue;
-                        if (x%2 == 1 && y%2 == 1) continue;
+                        if (x%2 == y%2) continue; // Cells are invalid, intersections are already handled.
+
+            // We need to introduce a new segment -- 
+                        // Locate the segment we're breaking
+                        for (int i=0; i<connections_a.size(); i++) {
+                                auto [x1, y1] = loc_to_xy(p, connections_a[i]);
+                                auto [x2, y2] = loc_to_xy(p, connections_b[i]);
+                                if ((x1+1 == x && x2-1 == x && y1 == y && y2 == y) ||
+                                        (y1+1 == y && y2-1 == y && x1 == x && x2 == x)) {
+                                        int other_connection = connections_b[i];
+                                        connections_b[i] = static_cast<int>(intersectionFlags.size()); // This endpoint
+                                        
+                                        connections_a.push_back(other_connection);
+                                        connections_b.push_back(static_cast<int>(intersectionFlags.size())); // This endpoint
+                                        break;
+                                }
+                        }
+                        // Add this dot to the end
+                        float xPos = min + (x/2.0f) * width_interval;
+                        float yPos = max - (y/2.0f) * height_interval;
+                        intersectionLocations.push_back(xPos);
+                        intersectionLocations.push_back(yPos);
 
             int flags = Flags::HAS_DOT;
             switch (p.grid[x][y].dot) {
@@ -206,15 +263,16 @@ void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
                     flags |= DOT_IS_INVISIBLE;
                     break;
             }
+            intersectionFlags.push_back(flags);
+                }
+        }
 
-            // Dot is already a point the grid, just overwrite the flags
-                        if (x%2 == 0 && y%2 == 0) {
-                                intersectionFlags[xy_to_loc(p, x, y)] |= flags;
-                                continue;
-                        }
+    // Gaps
+    for (int x=0; x<p.width; x++) {
+        for (int y=0; y<p.height; y++) {
+                        if (p.grid[x][y].gap == Cell::Gap::NONE) continue;
+                        if (x%2 == y%2) continue; // Cells are invalid, intersections are already handled.
 
-            // Else, we need to introduce a new segment
-                        // Locate the segment we're breaking
                         for (int i=0; i<connections_a.size(); i++) {
                                 auto [x1, y1] = loc_to_xy(p, connections_a[i]);
                                 auto [x2, y2] = loc_to_xy(p, connections_b[i]);
@@ -223,22 +281,35 @@ void PuzzleSerializer::WriteIntersections(const Puzzle& p, int id) {
                                         int other_connection = connections_b[i];
                                         connections_b[i] = static_cast<int>(intersectionFlags.size()); // This endpoint
                                         
-                                        connections_a.push_back(static_cast<int>(intersectionFlags.size())); // This endpoint
-                                        connections_b.push_back(other_connection);
+                                        connections_a.push_back(other_connection);
+                                        connections_b.push_back(static_cast<int>(intersectionFlags.size() + 1)); // Next endpoint
                                         break;
                                 }
                         }
-                        // Add this dot to the end
+            // Add the two halves of this gap to the end
                         float xPos = min + (x/2.0f) * width_interval;
                         float yPos = max - (y/2.0f) * height_interval;
-                        intersections.push_back(xPos);
-                        intersections.push_back(yPos);
-            intersectionFlags.push_back(flags);
+            // Reminder: Y goes from 0.0 (bottom) to 1.0 (top)
+            if (x%2 == 0) { // Vertical gap
+                            intersectionLocations.push_back(xPos);
+                            intersectionLocations.push_back(yPos + verti_gap_size / 2);
+                            intersectionLocations.push_back(xPos);
+                            intersectionLocations.push_back(yPos - verti_gap_size / 2);
+                intersectionFlags.push_back(Flags::HAS_NO_CONN | Flags::HAS_VERTI_CONN);
+                intersectionFlags.push_back(Flags::HAS_NO_CONN | Flags::HAS_VERTI_CONN);
+            } else if (y%2 == 0) { // Horizontal gap
+                            intersectionLocations.push_back(xPos - horiz_gap_size / 2);
+                            intersectionLocations.push_back(yPos);
+                            intersectionLocations.push_back(xPos + horiz_gap_size / 2);
+                            intersectionLocations.push_back(yPos);
+                intersectionFlags.push_back(Flags::HAS_NO_CONN | Flags::HAS_VERTI_CONN);
+                intersectionFlags.push_back(Flags::HAS_NO_CONN | Flags::HAS_VERTI_CONN);
+            }
                 }
         }
 
         _memory->WritePanelData<int>(id, NUM_DOTS, {static_cast<int>(intersectionFlags.size())});
-        _memory->WriteArray<float>(id, DOT_POSITIONS, intersections);
+        _memory->WriteArray<float>(id, DOT_POSITIONS, intersectionLocations);
         _memory->WriteArray<int>(id, DOT_FLAGS, intersectionFlags);
         _memory->WritePanelData<int>(id, NUM_CONNECTIONS, {static_cast<int>(connections_a.size())});
         _memory->WriteArray<int>(id, DOT_CONNECTION_A, connections_a);
@@ -262,7 +333,7 @@ void PuzzleSerializer::WriteDecorations(const Puzzle& p, int id) {
         _memory->WriteArray<int>(id, DECORATIONS, decorations);
 }
 
-std::tuple<int, int> PuzzleSerializer::loc_to_xy(const Puzzle& p, int location) {
+std::tuple<int, int> PuzzleSerializer::loc_to_xy(const Puzzle& p, int location) const {
     int height2 = (p.height - 1) / 2;
     int width2 = (p.width + 1) / 2;
 
@@ -271,7 +342,7 @@ std::tuple<int, int> PuzzleSerializer::loc_to_xy(const Puzzle& p, int location)
     return {x, y};
 }
 
-int PuzzleSerializer::xy_to_loc(const Puzzle& p, int x, int y) {
+int PuzzleSerializer::xy_to_loc(const Puzzle& p, int x, int y) const {
     int height2 = (p.height - 1) / 2;
     int width2 = (p.width + 1) / 2;
 
@@ -279,7 +350,7 @@ int PuzzleSerializer::xy_to_loc(const Puzzle& p, int x, int y) {
     return rowsFromBottom * width2 + x/2;
 }
 
-std::tuple<int, int> PuzzleSerializer::dloc_to_xy(const Puzzle& p, int location) {
+std::tuple<int, int> PuzzleSerializer::dloc_to_xy(const Puzzle& p, int location) const {
     int height2 = (p.height - 3) / 2;
     int width2 = (p.width - 1) / 2;
 
@@ -288,7 +359,7 @@ std::tuple<int, int> PuzzleSerializer::dloc_to_xy(const Puzzle& p, int location)
     return {x, y};
 }
 
-int PuzzleSerializer::xy_to_dloc(const Puzzle& p, int x, int y) {
+int PuzzleSerializer::xy_to_dloc(const Puzzle& p, int x, int y) const {
     int height2 = (p.height - 3) / 2;
     int width2 = (p.width - 1) / 2;
 
@@ -296,7 +367,7 @@ int PuzzleSerializer::xy_to_dloc(const Puzzle& p, int x, int y) {
     return rowsFromBottom * width2 + (x - 1)/2;
 }
 
-Cell::Dot PuzzleSerializer::FlagsToDot(int flags) {
+Cell::Dot PuzzleSerializer::FlagsToDot(int flags) const {
     if (!(flags & Flags::HAS_DOT)) return Cell::Dot::NONE;
     if (flags & Flags::DOT_IS_BLUE) {
         return Cell::Dot::BLUE;
@@ -308,3 +379,11 @@ Cell::Dot PuzzleSerializer::FlagsToDot(int flags) {
         return Cell::Dot::BLACK;
     }
 }
+
+int PuzzleSerializer::FindConnection(int i, const std::vector<int>& connections_a, const std::vector<int>& connections_b) const {
+    for (int j=0; j<connections_a.size(); j++) {
+            if (connections_a[j] == i) return connections_b[j];
+            if (connections_b[j] == i) return connections_a[j];
+    }
+    return -1;
+}
@@ -30,30 +30,31 @@ enum Color {
 struct Decoration {
     Shape type;
     Color color;
-    int polyshape;
+    int polyshape = 0;
     // For triangles only
-    int count;
+    int count = 0;
 };
 
 struct Cell {
-    bool start;
+    bool start = false;
     enum class Dir {NONE, LEFT, RIGHT, UP, DOWN};
-    Dir end;
-    std::shared_ptr<Decoration> decoration;
+    Dir end = Dir::NONE;
+    std::shared_ptr<Decoration> decoration = nullptr;
     enum class Dot {NONE, BLACK, BLUE, YELLOW, INVISIBLE};
-    Dot dot;
+    Dot dot = Dot::NONE;
     enum class Gap {NONE, BREAK, FULL};
-    Gap gap;
+    Gap gap = Gap::NONE;
 };
 
 struct Puzzle {
     int16_t height;
     int16_t width;
+    bool hasDecorations = false;
     std::vector<std::vector<Cell>> grid;
 
     enum class Symmetry {NONE, X, Y, XY};
-    Symmetry sym;
-    bool pillar;
+    Symmetry sym = Symmetry::NONE;
+    bool pillar = false;
 };
 
 class PuzzleSerializer {
@@ -65,13 +66,16 @@ public:
 private:
     // @Bug: Blue and orange are swapped?
     enum Flags {
-        IS_ENDPOINT =           0x1,
-        IS_STARTPOINT =         0x2,
-        DOT_IS_BLUE =         0x100,
-        DOT_IS_ORANGE =       0x200,
-        DOT_IS_INVISIBLE =   0x1000,
-        IS_GAP =            0x10000,
-        HAS_DOT =           0x40020,
+        IS_ENDPOINT =            0x1,
+        IS_STARTPOINT =          0x2,
+        IS_FULL_GAP =            0x8,
+        HAS_DOT =               0x20,
+        DOT_IS_BLUE =          0x100,
+        DOT_IS_ORANGE =        0x200,
+        DOT_IS_INVISIBLE =    0x1000,
+        HAS_NO_CONN =       0x100000,
+        HAS_VERTI_CONN =    0x200000,
+        HAS_HORIZ_CONN =    0x400000,
     };
 
     void ReadIntersections(Puzzle& p, int id);
@@ -79,12 +83,14 @@ private:
     void WriteIntersections(const Puzzle& p, int id);
     void WriteDecorations(const Puzzle& p, int id);
 
-    std::tuple<int, int> loc_to_xy(const Puzzle& p, int location);
-    int xy_to_loc(const Puzzle& p, int x, int y);
+    std::tuple<int, int> loc_to_xy(const Puzzle& p, int location) const;
+    int xy_to_loc(const Puzzle& p, int x, int y) const;
     // Decoration location
-    std::tuple<int, int> dloc_to_xy(const Puzzle& p, int location);
-    int xy_to_dloc(const Puzzle& p, int x, int y);
-    Cell::Dot FlagsToDot(int flags);
+    std::tuple<int, int> dloc_to_xy(const Puzzle& p, int location) const;
+    int xy_to_dloc(const Puzzle& p, int x, int y) const;
+    Cell::Dot FlagsToDot(int flags) const;
+    // Iterate connection lists for another location which is connected to us; return that other location.
+    int FindConnection(int i, const std::vector<int>& connections_a, const std::vector<int>& connections_b) const;
 
     std::shared_ptr<Memory> _memory;
 };