Scanline fill

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Pakz	Created : 30 January 2021 Edited : 30 January 2021 Language : Raylib c language Scanline fill Fast scanline fill routine in c language
#include "raylib.h" #define MAP_WIDTH 100 #define MAP_HEIGHT 100 int map[MAP_HEIGHT][MAP_WIDTH]; void scanlinefill(int x, int y,int value); void mapline(int x1, int y1, int x2, int y2,int value); int main(void) { // Initialization //-------------------------------------------------------------------------------------- const int screenWidth = 800; const int screenHeight = 450; InitWindow(screenWidth, screenHeight, "raylib example."); SetTargetFPS(60); // Set our game to run at 60 frames-per-second //-------------------------------------------------------------------------------------- mapline(0,0,MAP_WIDTH,MAP_HEIGHT,1); scanlinefill(50,48,1); // Main game loop while (!WindowShouldClose()) // Detect window close button or ESC key { // Update //---------------------------------------------------------------------------------- //---------------------------------------------------------------------------------- // Draw //---------------------------------------------------------------------------------- BeginDrawing(); ClearBackground(RAYWHITE); for(int y=0;y<MAP_HEIGHT;y++){ for(int x=0;x<MAP_WIDTH;x++){ if(map[y][x]==1){ DrawRectangle(x2,y2,2,2,RED); } }} EndDrawing(); //---------------------------------------------------------------------------------- } // De-Initialization //-------------------------------------------------------------------------------------- CloseWindow(); // Close window and OpenGL context //-------------------------------------------------------------------------------------- return 0; } // // scan line fill(flood) the map array if the value is 0 with value. // // void scanlinefill(int x, int y,int value){ if(x<0 \|\| x>=MAP_WIDTH \|\| y<0 \|\| y>=MAP_HEIGHT)return; if(map[y][x]==value)return; int x2=x; while(x2>-1 && map[y][x2]==0){ map[y][x2]=value; scanlinefill(x2,y-1,value); scanlinefill(x2,y+1,value); x2--; } x2=x+1; while(x2<MAP_WIDTH && map[y][x2]==0){ map[y][x2]=value; scanlinefill(x2,y-1,value); scanlinefill(x2,y+1,value); x2++; } } // // Bresenham line inside map[][] array. // void mapline(int x1, int y1, int x2, int y2,int value){ int dx; int dy; int sx; int sy; int e; dx = abs(x2 - x1); sx = -1; if(x1 < x2)sx = 1; dy = abs(y2 - y1); sy = -1; if(y1 < y2)sy = 1; if(dx < dy){ e = dx / 2; }else{ e = dy / 2; } bool exitloop=false; while(exitloop == false){ if(x1>-1 && x1<MAP_WIDTH && y1>-1 && y1<MAP_HEIGHT)map[x1][y1]=value; if(x1 == x2){ if(y1 == y2){ exitloop = true; } } if(dx > dy){ x1 += sx; e -= dy; if (e < 0){ e += dx; y1 += sy; } }else{ y1 += sy; e -= dx; if(e < 0){ e += dy; x1 += sx; } } } } --v
Latest Update I read about how to do a scanline fill a couple of years ago and tried to create it today. A scanline fill starts at x,y. It loops filling the line to the left and to the right. At every position you call the same function again but at one spot higher and one spot lower. There also is a bresenham line function in the code which I used to test the scanline fill. More raylib code at : https://github.com/Pakz001/Raylib-Examples

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Sunday, 31 January 2021, 08:46
Pakz	I had just tested the code with larger maps and it starts causing problems with the cache at larger maps(What is up with that in 2021?) I assumed this method had less problems with that but maybe I did something wrong. I had to get back to the method using a list that store the edges.

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