Wave Function Collapse Algorithm

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Pakz	Created : 25 September 2020 Edited : 26 September 2020 Language : raylib c Wave Function Collapse Algorithm
I think it was last year that I learned about the Wave Function Collapse algorithm. It is rather new. Only a few years ago it was created. There are no easy to understand tutorials on how to learn it. What it does is create levels from pieces of levels. Puzzling from one piece into to a whole level. Online there are a whole bunch of examples and a lot better than what I created. My version kind of creates some kind of dungeons. Here is where I finally learned how to create some working code : www.boristhebrave.com/2020/04/13/wave-function-collapse-explained/ edit: // // Wave Function Collapse - sort of... // // I barely understand how this works. It has taken me a number of tries and a whack load of hours // top get to this current point. The tutorials and explanations on the internet are not that clear and easy // to understand. // // In the example here I have a number of tiles. I pick a random tile from the valid ones and place it on the grid. // I then fix the neighbour tiles to fit this current position. Connected/unconnected. I keep placing random tiles // for a x amount of times. // There is a array that contains a list of all possible tiles(x,y,alltileslist). There are functions that check if a position on the grid // has connections to another position on the grid. This is used to unflag the tiles that are on the list to get // selected(one random) as a tile to be placed. // // The MAX_TILES is the amount of tiles that I have created to create the map with. I check the middle top/left/right/bottom // tile value to see if there is a connection(1). Experiment with making different tiles. // // I might(should) add comments to the code later. // #include "raylib.h" #define MAP_WIDTH 14 #define MAP_HEIGHT 12 #define MAX_TILES 15 static void newmap(void); static void resetmap(void); // If the selected map position has a connection the l/r/u/d side than return true/false static bool domainhasleftsidedconnections(int x,int y); static bool domainhasrightsidedconnections(int x,int y); static bool domainhastopsidedconnections(int x,int y); static bool domainhasbottomsidedconnections(int x,int y); // Remove every tile flag from l/r/u/d. static void removeleftsidedconnections(int x,int y); static void removerightsidedconnections(int x,int y); static void removetopsidedconnections(int x,int y); static void removebottomsidedconnections(int x,int y); // Select a random tile from the list of available tiles. static void setrandomtile(int x,int y); // Update the current map position checking l/r/u/d for connections and setting // the flag for can use or can not use with setrandomtile. static void updatedomain(int x,int y); // create our final tilemap. static void finishmap(void); // Our tile array. 3by3 grid of x amount of tiles static int tile[3][3][MAX_TILES] = {0}; // Our work map. We have every tile set up there. -1 if not usable or 1 if usable. static int map[MAP_WIDTH][MAP_HEIGHT][MAX_TILES] = {0}; // This is a array we use to draw the map on the screen static int tilemap[MAP_WIDTH][MAP_HEIGHT] = {0}; int main(void) { // Initialization //-------------------------------------------------------------------------------------- const int screenWidth = 800; const int screenHeight = 450; InitWindow(screenWidth, screenHeight, "raylib example."); // // These are the tiles with which the map will be generated. You can set the amount you want to use in the // define MAX_TILES x // The code checks the connections between these tiles by reading if a 1 is on the center top/left/right/bottom. // Also the draw routine draws the 1's as black. // // You could change(experiment!) and for instance use maybe 4 tiles and see the output. You can change the depth in the // newmap() function for how many times a tile is going to be selected and fit into the map. int tile1[3][3] = { {0,0,0}, {1,1,1}, {0,0,0}}; int tile2[3][3] = { {0,1,0}, {0,1,0}, {0,1,0}}; int tile3[3][3] = { {1,1,1}, {1,1,1}, {1,1,1}}; int tile4[3][3] = { {0,1,0}, {1,1,1}, {0,1,0}}; int tile5[3][3] = { {0,1,0}, {1,1,0}, {0,0,0}}; int tile6[3][3] = { {0,1,0}, {0,1,1}, {0,0,0}}; int tile7[3][3] = { {0,0,0}, {1,1,0}, {0,1,0}}; int tile8[3][3] = { {0,0,0}, {0,1,1}, {0,1,0}}; int tile9[3][3] = { {0,1,0}, {1,1,1}, {0,0,0}}; int tile10[3][3] = { {0,1,0}, {0,1,1}, {0,1,0}}; int tile11[3][3] = { {0,0,0}, {1,1,1}, {0,1,0}}; int tile12[3][3] = { {0,1,0}, {1,1,0}, {0,1,0}}; int tile13[3][3] = { {1,1,0}, {1,1,0}, {1,1,0}}; int tile14[3][3] = { {0,1,1}, {0,1,1}, {0,1,1}}; int tile15[3][3] = { {1,1,1}, {1,1,1}, {1,1,1}}; // // Here we copy each individual tile into a single array that we will // use in the code. for(int i=0;i<MAX_TILES;i++){ for(int y=0;y<3;y++){ for(int x=0;x<3;x++){ switch (i){ case 0: tile[x][y][i] = tile1[x][y]; break; case 1: tile[x][y][i] = tile2[x][y]; break; case 2: tile[x][y][i] = tile3[x][y]; break; case 3: tile[x][y][i] = tile4[x][y]; break; case 4: tile[x][y][i] = tile5[x][y]; break; case 5: tile[x][y][i] = tile6[x][y]; break; case 6: tile[x][y][i] = tile7[x][y]; break; case 7: tile[x][y][i] = tile8[x][y]; break; case 8: tile[x][y][i] = tile9[x][y]; break; case 9: tile[x][y][i] = tile10[x][y]; break; case 10: tile[x][y][i] = tile11[x][y]; break; case 11: tile[x][y][i] = tile12[x][y]; break; case 12: tile[x][y][i] = tile13[x][y]; break; case 13: tile[x][y][i] = tile14[x][y]; break; case 14: tile[x][y][i] = tile15[x][y]; break; } } } } // Here we generate the first map newmap(); SetTargetFPS(10); // Set our game to run at 60 frames-per-second //-------------------------------------------------------------------------------------- int cnt=0; // Main game loop while (!WindowShouldClose()) // Detect window close button or ESC key { // Update //---------------------------------------------------------------------------------- //--------------------------------------------------------------------------------- cnt++; if(IsKeyReleased(KEY_SPACE) \|\| cnt>4){ newmap(); cnt=0; } // Draw //---------------------------------------------------------------------------------- BeginDrawing(); ClearBackground(RAYWHITE); for (int y = 0; y< MAP_HEIGHT ; y++) { for (int x = 0; x< MAP_WIDTH ; x++) { int x3 = x48; int y3 = y32; for(int y2=0;y2<3;y2++){ for(int x2=0;x2<3;x2++){ if( tile[x2][y2][tilemap[x][y]]==1 )DrawRectangle(x3+x216,y3+y212,16,12,BLACK); } } } } DrawText("Press space for new map.", 100, screenHeight-40, 40, LIGHTGRAY); EndDrawing(); //---------------------------------------------------------------------------------- } // De-Initialization //-------------------------------------------------------------------------------------- CloseWindow(); // Close window and OpenGL context //-------------------------------------------------------------------------------------- return 0; } void newmap(){ // Here we reset the map. Meaning nothing will be in the memory. resetmap(); // here we generate the new map. I have set the depth to a number where it generates // output that I thought was ok! int depth=GetRandomValue(100,400); for(int i=0;i<depth;i++){ setrandomtile(GetRandomValue(0,MAP_WIDTH-1),GetRandomValue(0,MAP_HEIGHT-1)); } // Here we copy the remaining tile into the tilemap that we use to draw it onto the screen. finishmap(); }; void finishmap(){ for(int y=0;y<MAP_HEIGHT;y++){ for(int x=0;x<MAP_WIDTH;x++){ for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]>-1){ tilemap[x][y] = i; } } }} }; void resetmap(){ for(int y=0;y<MAP_HEIGHT;y++){ for(int x=0;x<MAP_WIDTH;x++){ for(int i=0;i<MAX_TILES;i++){ map[x][y][i] = 1; // set every tile flag to usable(1) } } } }; bool domainhasleftsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return false; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[0][1][i]==1){ return true;//the tile flag has a left side } } return false;//the map array has no tiles connecting on the left side }; bool domainhasrightsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return false; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[2][1][i]==1){ return true; } } return false; }; bool domainhastopsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return false; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[1][0][i]==1){ return true; } } return false; }; bool domainhasbottomsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return false; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[1][2][i]==1){ return true; } } return false; }; void removeleftsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[0][1][i]==1){ //if the flag of the tile is enabled(1) and the tile has a connection on the left(x)and center(y) spot map[x][y][i]=-1; // disable the flag } } }; void removerightsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[2][1][i]==1){ map[x][y][i]=-1; } } }; void removetopsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[1][0][i]==1){ map[x][y][i]=-1; } } }; void removebottomsidedconnections(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return; for(int i=0;i<MAX_TILES;i++){ if(map[x][y][i]==1 && tile[1][2][i]==1){ map[x][y][i]=-1; } } }; void setrandomtile(int x,int y){ bool exitloop=false; int count=0; while(exitloop==false){ count++; int val=GetRandomValue(0,MAX_TILES-1);//get a random number if(map[x][y][val]>-1){ //if the random number inside the map flag position is enabled(on the list!) for(int i=0;i<MAX_TILES;i++){ //disable every flag map[x][y][i]=-1; } map[x][y][val]=1;//enable the one we randomly created exitloop = true; break; } if(count>500)exitloop=true;//if anything goes wrong than exit } // Update around the new tile so that the connections make sense updatedomain(x-1,y); updatedomain(x+1,y); updatedomain(x,y-1); updatedomain(x,y+1); }; void updatedomain(int x,int y){ if(x<0 \|\| y<0 \|\| x>=MAP_WIDTH \|\| y>=MAP_HEIGHT)return; // Enable every tile flag for(int i=0;i<MAX_TILES;i++){ map[x][y][i]=1; } // check sides and disable tiles pieces with connections that are not present. if(domainhasbottomsidedconnections(x,y-1)==false)removetopsidedconnections(x,y); if(domainhastopsidedconnections(x,y+1)==false)removebottomsidedconnections(x,y); if(domainhasleftsidedconnections(x+1,y)==false)removerightsidedconnections(x,y); if(domainhasrightsidedconnections(x-1,y)==false)removeleftsidedconnections(x,y); }; --v Here one of the outputs: Here a video showing my code and the output levels. View on YouTube My code was made in Raylib using the c language. (github user : pakz001)

Comments
Saturday, 26 September 2020, 01:42
Pakz	Bump! I commented the code and put that version here on the site into a code box. Maybe someone wil find it useful.
Saturday, 26 September 2020, 05:54
Jayenkai	That looks handy for making some nice level layout and such. Still waiting for that epic game that makes use of all these generators, and your awesome sprites. Come on, Pakz!!
Saturday, 26 September 2020, 07:16
Pakz	I had almost started with porting my 'dude space mining' game from monkey2 to raylib and expand on that. But I want to spend a lot more time learning how to do reasonable pixelart. Knowing me this is going to take me 'a while' These were done recently for rpg inventories : still a newb though !
Saturday, 26 September 2020, 07:23
Jayenkai	"newb" my arse! Those would definitely work in a game.
Thursday, 01 October 2020, 09:16
Pakz	A little bit more about the wave function collapse. I have had more time to think about it. It is a sort of auto tiling algorithm. When in sim city you placed a road into a straight direction and then went into another direction the game would auto change the corner road to be a corner tile. Also it would handle all directions a road would go by placing the rights tiles there. No need to select each tile from the menu. This wfc algorithm is somewhat similar. It places a random tile and based on that tile it would select tiles besides it that connect with that one. Say you have a flower and you start at the bottom. Its base can only go up so that tile would be selected or the flower part. At random it could be a large or small flower. There are a bunch of tricks and mods that can be done to get different behaviour and output but auto tiling seems to be what it is in its most primitive form.
Thursday, 01 October 2020, 10:42
cyangames	After giving it a readup it sure seems interesting, I wander if it could be used to create something larger than expected on a lil 32kb NES cart then.... Hmmmmm

Wave Function Collapse Algorithm

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