add optional opts param and swappable get_node

common.lua

@@ -40,10 +40,9 @@ function isogen.get_cube_position(center_x, center_y, cube_len, _, pos)
     return x, y
 end
 
-function isogen.probe_position(min, max, pos, ipos, list)
-    list = list or {}
+function isogen.probe_position(min, max, pos, ipos, list, get_node)
     while vector.in_area(pos, min, max) do
-        local node = minetest.get_node(pos)
+        local node = get_node(pos)
         local color = isogen.get_color(node)
         if color then
             local rel_pos = vector.subtract(pos, min)
@@ -67,7 +66,6 @@ function isogen.probe_position(min, max, pos, ipos, list)
         end
         pos = vector.add(pos, ipos)
     end
-    return list
 end
 
 local function flip_pos(pos, max, axis)

common.spec.lua

@@ -65,6 +65,6 @@ mtt.register("probe_position", function(callback)
     local pos = vector.new(0, 15, 0)
     local ipos = vector.new(1, -1, 1)
 
-    isogen.probe_position(pos1, pos2, pos, ipos)
+    isogen.probe_position(pos1, pos2, pos, ipos, {}, minetest.get_node)
     callback()
 end)

draw.lua

@@ -18,15 +18,17 @@ local function color_adjust(c, v)
     }
 end
 
-function isogen.draw(pos1, pos2, cube_len)
+function isogen.draw(pos1, pos2, opts)
+    opts = opts or {}
+    opts.cube_len = opts.cube_len or 24
+    opts.get_node = opts.get_node or minetest.get_node
     local min, max = vector.sort(pos1, pos2)
-    cube_len = cube_len or 24
 
     minetest.load_area(min, max)
 
     local size = vector.add(vector.subtract(max, min), 1)
-    local width, height = isogen.calculate_image_size(size, cube_len)
-    local center_x, center_y = isogen.get_center_cube_offset(size, cube_len)
+    local width, height = isogen.calculate_image_size(size, opts.cube_len)
+    local center_x, center_y = isogen.get_center_cube_offset(size, opts.cube_len)
     local canvas = isogen.create_canvas(width, height)
 
     local ipos = vector.new(1, -1, 1)
@@ -35,21 +37,21 @@ function isogen.draw(pos1, pos2, cube_len)
     -- top layer
     for x=min.x, max.x do
         for z=min.z, max.z do
-            isogen.probe_position(min, max, vector.new(x, max.y, z), ipos, list)
+            isogen.probe_position(min, max, vector.new(x, max.y, z), ipos, list, opts.get_node)
         end
     end
 
     -- left layer (without top stride)
     for x=min.x, max.x do
         for y=min.y, max.y-1 do
-            isogen.probe_position(min, max, vector.new(x, y, min.z), ipos, list)
+            isogen.probe_position(min, max, vector.new(x, y, min.z), ipos, list, opts.get_node)
         end
     end
 
     -- right layer (without top and left stride)
     for z=min.z+1, max.z do
         for y=min.y, max.y-1 do
-            isogen.probe_position(min, max, vector.new(min.x, y, z), ipos, list)
+            isogen.probe_position(min, max, vector.new(min.x, y, z), ipos, list, opts.get_node)
         end
     end
 
@@ -60,8 +62,8 @@ function isogen.draw(pos1, pos2, cube_len)
     for _, entry in ipairs(list) do
         local rel_pos = vector.subtract(entry.pos, min)
         local color = entry.color
-        local x, y = isogen.get_cube_position(center_x, center_y, cube_len, 0, rel_pos)
-        isogen.draw_cube(canvas, cube_len, x, y, color, color_adjust(color, -10), color_adjust(color, 10))
+        local x, y = isogen.get_cube_position(center_x, center_y, opts.cube_len, 0, rel_pos)
+        isogen.draw_cube(canvas, opts.cube_len, x, y, color, color_adjust(color, -10), color_adjust(color, 10))
     end
 
     return canvas:png()

draw_cube.spec.lua

@@ -7,7 +7,7 @@ mtt.register("draw_cube", function(callback)
 
     local canvas = isogen.create_canvas(800, 600)
 
-    isogen.draw_cube(canvas, 24, 0, 0, red, green, blue)
+    isogen.draw_cube(canvas, 24, 0, 0, red, green, blue, minetest.get_node)
     local png = canvas:png()
 
     local path = minetest.get_worldpath() .. "/test.png"

draw_map.lua

@@ -1,5 +1,7 @@
 
-function isogen.draw_map(pos1, pos2)
+function isogen.draw_map(pos1, pos2, opts)
+    opts = opts or {}
+    opts.get_node = opts.get_node or minetest.get_node
     pos1, pos2 = vector.sort(pos1, pos2)
 
     minetest.load_area(pos1, pos2)
@@ -18,7 +20,7 @@ function isogen.draw_map(pos1, pos2)
             -- up-down
             for y=pos2.y,pos1.y,-1 do
                 local pos = vector.new(x, y, z)
-                local node = minetest.get_node(pos)
+                local node = opts.get_node(pos)
                 local color = isogen.get_color(node)
                 if color then
                     table.insert(list, color)

readme.md

@@ -32,7 +32,7 @@ Supported node-colors:
 
 # Api
 
-## `isogen.draw(pos1, pos2, cube_len?)`
+## `isogen.draw(pos1, pos2, opts?)`
 
 Renders an isometric image and returns the png data
 
@@ -40,15 +40,18 @@ Example:
 ```lua
 local pos1 = vector.new(0,0,0)
 local pos2 = vector.new(16,16,16) -- NOTE: larger regions require more memory
-local cube_len = 24 -- multiple of 4 and greater than 4 pixels
+local opts = { -- optional
+    cube_len = 24, -- optional: multiple of 4 and greater than 4 pixels
+    get_node = minetest.get_node -- optional: the get_node() function to use
+}
 
 -- render and save to world-directory
-local png = isogen.draw(pos1, pos2, cube_len)
+local png = isogen.draw(pos1, pos2, opts)
 local path = minetest.get_worldpath() .. "/iso.png"
 minetest.safe_file_write(path, png)
 ```
 
-## `isogen.draw_map(pos1, pos2)`
+## `isogen.draw_map(pos1, pos2, opts?)`
 
 Renders a map image and returns the png data
 
@@ -56,9 +59,12 @@ Example:
 ```lua
 local pos1 = vector.new(0,0,0)
 local pos2 = vector.new(16,16,16) -- NOTE: larger regions require more memory
+local opts = { -- optional
+    get_node = minetest.get_node -- optional: the get_node() function to use
+}
 
 -- render and save to world-directory
-local png = isogen.draw_map(pos1, pos2)
+local png = isogen.draw_map(pos1, pos2, opts)
 local path = minetest.get_worldpath() .. "/map.png"
 minetest.safe_file_write(path, png)
 ```