initial commit

2019-01-03 17:39:40 +01:00
commit d853f9f14c
3 changed files with 255 additions and 0 deletions
--- a/grid.nim
+++ b/grid.nim
@@ -0,0 +1,73 @@
+import random
+from times import epochTime
+type Grid* = object 
+    rows*, columns* : uint32
+    data : seq[uint32]
+
+proc newGrid*(rows, columns : uint32) : Grid =
+    Grid(
+        rows: rows, 
+        columns: columns,
+        data: newSeq[uint32]((rows * columns + 8 - 1) div 8)
+    )
+
+proc get(grid : Grid, x, y : uint32) : bool =
+    assert x < grid.columns
+    assert y < grid.rows
+    let index = y * grid.columns + x
+    (grid.data[index div 8] and (1u32 shl (index mod 8))) != 0
+
+proc set(grid : var Grid, x, y : uint32, value : bool) : void =
+    assert x < grid.columns
+    assert y < grid.rows
+    let index = y * grid.columns + x
+    grid.data[(index div 8)] = 
+        if value:
+            grid.data[(index div 8)] or (1u32 shl (index mod 8))
+        else:
+            grid.data[(index div 8)] and (not (1u32 shl (index mod 8)))
+    
+template `[]`*(grid : Grid, x,y : uint32) : bool =
+    get(grid, x, y)
+
+template `[]=`*(grid : Grid, x,y : uint32, value : bool) =
+    set(grid, x, y, value)
+
+proc next_step*(old_grid, new_grid : var Grid) =
+    for x in 0..<old_grid.columns:
+        for y in 0..<old_grid.rows:
+            var alive_neighbours = 0 
+            if old_grid[(x+1) mod old_grid.columns, y]:
+                alive_neighbours += 1
+            if old_grid[(x+1) mod old_grid.columns, (y+1) mod old_grid.rows]:
+                alive_neighbours += 1
+            if old_grid[(x+1) mod old_grid.columns, (y-1) mod old_grid.rows]:
+                alive_neighbours += 1
+            if old_grid[(x-1) mod old_grid.columns, y]:
+                alive_neighbours += 1
+            if old_grid[(x-1) mod old_grid.columns, (y + 1) mod old_grid.rows]:
+                alive_neighbours += 1
+            if old_grid[(x-1) mod old_grid.columns, (y - 1) mod old_grid.rows]:
+                alive_neighbours += 1
+            if old_grid[x mod old_grid.columns, (y + 1) mod old_grid.rows]:
+                alive_neighbours += 1
+            if old_grid[x mod old_grid.columns, (y - 1) mod old_grid.rows]:
+                alive_neighbours += 1
+            
+            if old_grid[x, y]:
+                if alive_neighbours < 2 or alive_neighbours > 3:
+                    new_grid[x, y] = false
+                else:
+                    new_grid[x, y] = true
+            elif alive_neighbours == 3:
+                new_grid[x, y] = true
+            else:
+                new_grid[x, y] = false
+
+proc rand_init*(grid : var Grid) =
+    var rand = initRand(epochTime().int64)
+    for x in 0..<grid.columns:
+        for y in 0..<grid.rows:
+            grid[x, y] = (rand.next() mod 2) != 0
+
+