marker util

init.lua

@@ -13,6 +13,7 @@ dofile(MP .. "/entity.lua")
 dofile(MP .. "/preview.lua")
 dofile(MP .. "/api.lua")
 dofile(MP .. "/common.lua")
+dofile(MP .. "/markers.lua")
 dofile(MP .. "/placements/mapblock_lib.lua")
 dofile(MP .. "/placements/dummy.lua")
 dofile(MP .. "/conditions.lua")

markers.lua

@@ -0,0 +1,38 @@
+
+-- type -> texture-name
+local textures = {
+    arrow = "building_lib_arrow.png"
+}
+
+-- name -> vector
+-- assuming texture points upwards originally
+local rotations = {
+    ["z-"] = { x=math.pi/2, y=0, z=0 },
+    ["z+"] = { x=math.pi/2, y=0, z=math.pi },
+    ["x+"] = { x=math.pi/2, y=0, z=math.pi/2 },
+    ["x-"] = { x=math.pi/2, y=0, z=-math.pi/2 }
+}
+
+function building_lib.create_marker(type, opts)
+    -- apply sane defaults
+    if not textures[type] then
+        type = "arrow"
+    end
+    opts = opts or {}
+    opts.pos = opts.pos or {}
+    opts.pos.x = opts.pos.x or 0
+    opts.pos.y = opts.pos.y or 0
+    opts.pos.z = opts.pos.z or 0
+    opts.size = opts.size or 10
+
+    if not rotations[opts.rotation] then
+        opts.rotation = "z-"
+    end
+
+    return {
+        texture = textures[type],
+        position = opts.pos,
+        rotation = rotations[opts.rotation],
+        size = {x=opts.size, y=opts.size}
+    }
+end

preview.lua

@@ -48,7 +48,8 @@ function building_lib.show_preview(playername, texture, color, building_def, map
 		local unrotated_size = building_lib.get_building_size(building_def, 360 - rotation)
 
 		for _, marker in ipairs(building_def.markers) do
-			local rotated_position = mapblock_lib.rotate_pos(marker.position, unrotated_size, rotation)
+			local center_rel_pos = vector.add(marker.position, 0.5)
+			local rotated_position = mapblock_lib.rotate_pos(center_rel_pos, unrotated_size, rotation)
 			local node_pos = vector.multiply(vector.add(mapblock_pos1, rotated_position), 16)
 			node_pos = vector.subtract(node_pos, 0.5)
 			local z_rotation = marker.rotation.z