Add rail rendering (WIP)

init.lua

@@ -113,6 +113,8 @@ xmaps.create_map_item = function(pos, properties)
 			{ 150, 105,  55 }, -- more liquid
 			{  60,  35,  16 }, -- tree outline
 			{ 150, 105,  55 }, -- tree fill
+			{  60,  35,  15 }, -- rail line
+			{  60,  35,  15 }, -- rail line
 		}
 		for x = 1,size,1 do
 			for z = 1,size,1 do
@@ -166,6 +168,126 @@ xmaps.create_map_item = function(pos, properties)
 
 		local image = tga_encoder.image(pixels)
 
+		local positions = minetest.find_nodes_in_area_under_air(
+			minp,
+			maxp,
+			"group:rail"
+		)
+		RAIL = 10
+		for _, p in ipairs(positions) do
+			local z = p.z - minp.z + 1
+			local x = p.x - minp.x + 1
+			pixels[z][x] = { RAIL }
+		end
+		-- thin out diagonal lines
+		for z = 1,#pixels do
+			for x = 1,#pixels[z] do
+				if (
+				   RAIL == pixels[z][x][1] and
+				   x < #pixels[z] -1 and
+				   RAIL == pixels[z][x+1][1] and
+				   not ( RAIL == pixels[z][x+2][1] )
+				) then
+					local color = 0 + ( ( x + z + 1 ) % 2 )
+					pixels[z][x+1] = { color }
+				end
+				if (
+				   RAIL == pixels[z][x][1] and
+				   z < #pixels - 1 and
+				   RAIL == pixels[z+1][x][1] and
+				   not ( RAIL == pixels[z+2][x][1] )
+				) then
+					local color = 0 + ( ( x + z + 1 ) % 2 )
+					pixels[z+1][x] = { color }
+				end
+			end
+		end
+		for _, p in ipairs(positions) do
+			local z = p.z - minp.z + 1
+			local x = p.x - minp.x + 1
+			local draw_rail = (
+				z > 1 and
+				z < size - 1 and
+				x > 1 and
+				x < size - 1
+			)
+			if draw_rail then
+				local _ = { nil } -- transparent
+				local R = { 11 } -- line
+				local rail
+				local node_sw = minetest.get_node({
+				      x=p.x - 1,
+				      y=p.y,
+				      z=p.z - 1,
+				})
+				local node_se = minetest.get_node({
+				      x=p.x - 1,
+				      y=p.y,
+				      z=p.z + 1,
+				})
+				local node_nw = minetest.get_node({
+				      x=p.x + 1,
+				      y=p.y,
+				      z=p.z - 1,
+				})
+				local node_ne = minetest.get_node({
+				      x=p.x + 1,
+				      y=p.y,
+				      z=p.z + 1,
+				})
+				if (
+				   minetest.get_item_group(
+				      node_sw.name,
+				      "rail"
+				   ) > 0 or
+				   minetest.get_item_group(
+				      node_se.name,
+				      "rail"
+				   ) > 0 or
+				   minetest.get_item_group(
+				      node_nw.name,
+				      "rail"
+				   ) > 0 or
+				   minetest.get_item_group(
+				      node_ne.name,
+				      "rail"
+				   ) > 0
+				) then
+				   rail = {
+					{ R, _, R },
+					{ _, R, _ },
+					{ R, _, R },
+				      }
+				else
+				   rail = {
+				      { _, R, _ },
+				      { R, R, R },
+				      { _, R, _ },
+				   }
+				end
+				if 0 == ( x + z ) % 4 then
+				   rail = {}
+				end
+				assert( rail )
+				image:blit_icon(
+					rail,
+					{
+						x = x - 2,
+						z = z - 2,
+					},
+					{
+						[4] = true,
+						[5] = true,
+						[6] = true,
+						[7] = true,
+						[8] = true,
+						[9] = true,
+						[11] = true,
+					}
+				)
+			end
+		end
+
 		local positions = minetest.find_nodes_in_area(
 			minp,
 			maxp,
@@ -207,6 +329,8 @@ xmaps.create_map_item = function(pos, properties)
 						[7] = true,
 						[8] = true,
 						[9] = true,
+						[10] = true,
+						[11] = true,
 					}
 				)
 			end
@@ -279,6 +403,8 @@ xmaps.create_map_item = function(pos, properties)
 						[7] = true,
 						[8] = true,
 						[9] = true,
+						[10] = true,
+						[11] = true,
 					}
 				)
 			end
@@ -321,6 +447,8 @@ xmaps.create_map_item = function(pos, properties)
 						[7] = true,
 						[8] = true,
 						[9] = true,
+						[10] = true,
+						[11] = true,
 					}
 				)
 			end
@@ -362,6 +490,8 @@ xmaps.create_map_item = function(pos, properties)
 						[7] = true,
 						[8] = true,
 						[9] = true,
+						[10] = true,
+						[11] = true,
 					}
 				)
 			end