Improve scrape particle position for fence & sign

mods/rp_default/fence.lua

@@ -70,6 +70,7 @@ local function register_fence(name, def)
 	def_painted.tiles = {def.texture_top_painted, def.texture_top_painted, def.texture_side_painted}
 	def_painted.inventory_image = def.inventory_image.."^[hsl:0:-100:0"
 	def_painted.wield_image = def.wield_image.."^[hsl:0:-100:0"
+	def_painted._rp_paint_particle_pos = "cube_inside"
 	local name_painted = name .. "_painted"
 	minetest.register_node(name_painted, def_painted)
 end
@@ -238,6 +239,7 @@ local function register_fence_gate(name, def)
 	def_open_painted.tiles = {def.texture_top_painted, def.texture_top_painted, def.texture_side_painted, def.texture_side_painted, def.texture_front_painted}
 	def_open_painted.inventory_image = nil
 	def_open_painted.wield_image = nil
+	def_open_painted._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node(gate_id_open_painted, def_open_painted)
 
 	local def_closed_painted = table.copy(def_closed)
@@ -250,6 +252,7 @@ local function register_fence_gate(name, def)
 	def_closed_painted.tiles = {def.texture_top_painted, def.texture_top_painted, def.texture_side_painted, def.texture_side_painted, def.texture_front_painted}
 	def_closed_painted.inventory_image = def.inventory_image.."^[hsl:0:-100:0"
 	def_closed_painted.wield_image = def.wield_image.."^[hsl:0:-100:0"
+	def_closed_painted._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node(gate_id_closed_painted, def_closed_painted)
 end
 

mods/rp_paint/API.md

@@ -147,14 +147,26 @@ Removes color of a paintable node at `pos`, returning it to its
 Returns `true` on success, `false` on failure or if node was not painted
 or if node does not support an unpainted state.
 
-### `rp_paint.scrape_color(pos)`
+### `rp_paint.scrape_color(pos, pointed_thing)`
 
 Same as `rp_paint.remove_color`, but will also play a “scraping-off”
 sound effect (`_rp_scrape`) and show a particle effect.
 
 The recommended use case for this function is tools.
 
-By default, the particles will be based on the node itself by adding
+* `pos`: Position of node to scrape off
+* `pointed_thing`: A pointed thing table specifying where the position
+                   was pointed to (used for particle position)
+
+See also "Scrape particle fine-tuning" for details on how to customize
+the scrape particles for nodes.
+
+## Appendix
+
+### Scrape particle fine-tuning
+
+By default, when scraping off a node, the particles will be based on
+the node itself by adding
 `node = <the node that was scraped>` to the particle spawner
 definition. This looks good for most nodes but sometimes it doesn’t.
 
@@ -164,6 +176,13 @@ particle effect on. If set to `false`, there will be no scraping
 particles.
 (Example: `_rp_paint_particle_node = "rp_default:planks_painted"`)
 
+With the field `_rp_paint_particle_pos`, you can specify a custom
+position for the particles:
+
+* `"flat_above"` (default): Particles appear in front of the node
+                 where it was scraped
+* `"cube_inside"`: Particles appear inside the scraped node
+
 ### Color IDs
 
 Each color has an unique numeric ID. The following IDs are available:

mods/rp_paint/init.lua

@@ -247,12 +247,18 @@ rp_paint.add_scrape_particles = function(pos, oldnode, direction)
 	if not olddef then
 		return false
 	end
+	local ptype = olddef._rp_paint_particle_pos
+	local rpos = table.copy(pos)
 	-- Spawn particles where we scrape
 	local offset1, offset2
 	local SQ = 0.48 -- "radius" of square
 	local H1 = 0.48 -- min. distance from node
 	local H2 = 0.49 -- max. distance from node
-	if direction.y > 0 then
+	if ptype == "cube_inside" then
+		offset1 = {x=-SQ, y=-SQ, z=-SQ}
+		offset2 = {x=SQ, y=SQ, z=SQ}
+		rpos = vector.subtract(rpos, direction)
+	elseif direction.y > 0 then
 		offset1 = {x=-SQ, y=-H2, z=-SQ}
 		offset2 = {x=SQ, y=-H1, z=SQ}
 	elseif direction.y < 0 then
@@ -290,11 +296,20 @@ rp_paint.add_scrape_particles = function(pos, oldnode, direction)
 	else
 		particle_node = oldnode
 	end
+	local minpos, maxpos
+	if ptype == "flat_under" then
+		rpos = vector.subtract(rpos, direction)
+		minpos = vector.add(rpos, offset1)
+		maxpos = vector.add(rpos, offset2)
+	else
+		minpos = vector.add(rpos, offset1)
+		maxpos = vector.add(rpos, offset2)
+	end
 	minetest.add_particlespawner({
 		amount = math.random(10, 20),
 		time = 0.1,
-		minpos = vector.add(pos, offset1),
-		maxpos = vector.add(pos, offset2),
+		minpos = minpos,
+		maxpos = maxpos,
 		minvel = {x=-0.2, y=0, z=-0.2},
 		maxvel = {x=0.2, y=2, z=0.2},
 		minacc = {x=0, y=-GRAVITY, z=0},

mods/rp_signs/init.lua

@@ -1076,6 +1076,7 @@ local function register_sign(id, def)
 	sdef_p.inventory_image = def.inv_image.."^[hsl:0:-100:0"
 	sdef_p.wield_image = def.inv_image.."^[hsl:0:-100:0"
 	sdef_p.drop = "rp_signs:"..id
+	sdef_p._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node("rp_signs:"..id.."_painted", sdef_p)
 
 	-- Wall sign, rotated by 90°, painted
@@ -1095,6 +1096,7 @@ local function register_sign(id, def)
 	sdef_r90_p.inventory_image = "("..def.inv_image..")^[transformR90^[hsl:0:-100:0"
 	sdef_r90_p.wield_image = "("..def.inv_image..")^[transformR90^[hsl:0:-100:0"
 	sdef_r90_p.drop = "rp_signs:"..id
+	sdef_r90_p._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node("rp_signs:"..id.."_r90_painted", sdef_r90_p)
 
 	-- Standing sign, painted
@@ -1116,6 +1118,7 @@ local function register_sign(id, def)
 	ssdef_p.inventory_image = "("..def.inv_image_standing..")^[hsl:0:-100:0"
 	ssdef_p.wield_image = "("..def.inv_image_standing..")^[hsl:0:-100:0"
 	ssdef_p.drop = "rp_signs:"..id.."_standing"
+	ssdef_p._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node("rp_signs:"..id.."_standing_painted", ssdef_p)
 
 	-- Hanging sign, painted
@@ -1137,6 +1140,7 @@ local function register_sign(id, def)
 	shdef_p.inventory_image = nil
 	shdef_p.wield_image = nil
 	shdef_p.drop = "rp_signs:"..id.."_standing"
+	shdef_p._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node("rp_signs:"..id.."_hanging_painted", shdef_p)
 
 	-- Sideways sign, painted
@@ -1157,6 +1161,7 @@ local function register_sign(id, def)
 	stsdef_p.inventory_image = nil
 	stsdef_p.wield_image = nil
 	stsdef_p.drop = "rp_signs:"..id.."_standing"
+	stsdef_p._rp_paint_particle_pos = "cube_inside"
 	minetest.register_node("rp_signs:"..id.."_side_painted", stsdef_p)
 
 	register_sign_page(id, {