Add bumpmapping and parallax occlusion testing nodes to devtest (#9242)

games/devtest/mods/testnodes/mod.conf

@@ -1,2 +1,3 @@
 name = testnodes
 description = Contains a bunch of basic example nodes for demonstrative purposes, development and testing
+depends = stairs

games/devtest/mods/testnodes/textures.lua

@@ -71,3 +71,52 @@ for a=1,#alphas do
 		groups = { dig_immediate = 3 },
 	})
 end
+
+
+-- Bumpmapping and Parallax Occlusion
+
+-- This node has a normal map which corresponds to a pyramid with sides tilted
+-- by an angle of 45°, i.e. the normal map contains four vectors which point
+-- diagonally away from the surface (e.g. (0.7, 0.7, 0)),
+-- and the heights in the height map linearly increase towards the centre,
+-- so that the surface corresponds to a simple pyramid.
+-- The node can help to determine if e.g. tangent space transformations work
+-- correctly.
+-- If, for example, the light comes from above, then the (tilted) pyramids
+-- should look like they're lit from this light direction on all node faces.
+-- The white albedo texture has small black indicators which can be used to see
+-- how it is transformed ingame (and thus see if there's rotation around the
+-- normal vector).
+minetest.register_node("testnodes:height_pyramid", {
+	description = "Bumpmapping and Parallax Occlusion Tester (height pyramid)",
+	tiles = {"testnodes_height_pyramid.png"},
+	groups = {dig_immediate = 3},
+})
+
+-- The stairs nodes should help to validate if shading works correctly for
+-- rotated nodes (which have rotated textures).
+stairs.register_stair_and_slab("height_pyramid", "experimantal:height_pyramid",
+	{dig_immediate = 3},
+	{"testnodes_height_pyramid.png"},
+	"Bumpmapping and Parallax Occlusion Tester Stair (height pyramid)",
+	"Bumpmapping and Parallax Occlusion Tester Slab (height pyramid)")
+
+-- This node has a simple heightmap for parallax occlusion testing and flat
+-- normalmap.
+-- When parallax occlusion is enabled, the yellow scrawl should stick out of
+-- the texture when viewed at an angle.
+minetest.register_node("testnodes:parallax_extruded", {
+	description = "Parallax Occlusion Tester",
+	tiles = {"testnodes_parallax_extruded.png"},
+	groups = {dig_immediate = 3},
+})
+
+-- Analogously to the height pyramid stairs nodes,
+-- these nodes should help to validate if parallax occlusion works correctly for
+-- rotated nodes (which have rotated textures).
+stairs.register_stair_and_slab("parallax_extruded",
+	"experimantal:parallax_extruded",
+	{dig_immediate = 3},
+	{"testnodes_parallax_extruded.png"},
+	"Parallax Occlusion Tester Stair",
+	"Parallax Occlusion Tester Slab")