add rotation field to obj

data/scripts/classes/obj.lua

@@ -3,6 +3,7 @@
 ---@field texture string
 ---@field texture_size integer
 ---@field position Vector3
+---@field rotation Vector3
 ---@field triangles table
 local Obj = {}
 
@@ -50,7 +51,7 @@ function Obj.create(model, texture, position)
     texture = texture.file,
     texture_size = texture.size,
     position = pos:copy(),
-
+    rotation = Vector3(),
     triangles = {}
   }
   obj.position = obj.position:copy()
@@ -112,12 +113,19 @@ function Obj.create(model, texture, position)
   return obj
 end
 
+local function rotate_vertex(obj, v)
+  local vec = Vector3(v)
+  --- YXZ (yaw pitch roll) minimizes gimbal lock
+  -- return vec:rotate(Vector3.UP, obj.rotation.y):rotate(Vector3.LEFT, obj.rotation.x):rotate(Vector3.FORWARD, obj.rotation.z)
+  return vec:rotate(Vector3.UP, obj.rotation.y):rotate(Vector3.LEFT, obj.rotation.x):rotate(Vector3.FORWARD, obj.rotation.z)
+end
+
 function Obj:draw()
   for _, triangle in ipairs(self.triangles) do
     local newt = util.shallow_copy(triangle)
-    newt.v0 = Vector3(triangle.v0) + self.position
+    newt.v0 = rotate_vertex(self, triangle.v0) + self.position
-    newt.v1 = Vector3(triangle.v1) + self.position
+    newt.v1 = rotate_vertex(self, triangle.v1) + self.position
-    newt.v2 = Vector3(triangle.v2) + self.position
+    newt.v2 = rotate_vertex(self, triangle.v2) + self.position
     draw_triangle(newt)
   end
 end

data/scripts/game.lua

@@ -5,7 +5,7 @@ local List = require "types.list"
 
 local Obj = require "classes.obj"
 
-local cube = Obj.create("models/unit_cube.obj", {file = "images/measure002a.png", size = 512}, Vector3(0, 1, 0))
+local cube = Obj.create("models/unit_cube.obj", {file = "images/measure002a.png", size = 512}, Vector3(0, 1, 1))
 
 local Feed = require "classes.feed"
 ---@type List
@@ -44,7 +44,7 @@ end
 function game_tick()
   -- ctx.initialization_needed is true first frame and every time dynamic reload is performed
   if ctx.initialization_needed then
-    audio_play{audio = "music/bg1.xm", loops = true, channel = "music"}
+    -- audio_play{audio = "music/bg1.xm", loops = true, channel = "music"}
     player.ThrowPressed:connect(create_feed)
 
     -- spawn some ducks
@@ -86,7 +86,9 @@ function game_tick()
     texture_region = { x = 0, y = 0, w = 512, h = 512 },
   }
   draw_quad(util.merge(q, params))
-  cube.position.x = math.sin(ctx.frame_number * 0.01)
+  cube.position.y = math.sin(ctx.frame_number * 0.05)
-  cube.position.z = math.cos(ctx.frame_number * 0.01)
+  -- cube.position.z = math.cos(ctx.frame_number * 0.01)
+  cube.rotation.x = cube.rotation.x + 0.01
+  cube.rotation.z = cube.rotation.z + 0.01
   cube:draw()
 end

data/scripts/types/vector3.lua

@@ -220,14 +220,30 @@ function Vector3:rotated(axis, angle)
     return vaxis
   end
 
----@diagnostic disable-next-line: undefined-field
   vaxis = vaxis:normalized()
   local cosa = math.cos(angle)
   local sina = math.sin(angle)
   -- __mul is only defined for the left operand (table), numbers don't get metatables.
   -- as such, the ordering of operations here is specific
-  local v = (self * cosa) + (vaxis * ((1 - cosa) * self:dot(vaxis))) + (vaxis:cross(self) * sina)
+  return (self * cosa) + (vaxis * ((1 - cosa) * self:dot(vaxis))) + (vaxis:cross(self) * sina)
-  return Vector3(v)
+end
+
+---In-place version of rotated.
+---@param axis Vector3
+---@param angle number
+---@return Vector3
+function Vector3:rotate(axis, angle)
+  local cosa = math.cos(angle)
+  local sina = math.sin(angle)
+
+  local dot = self:dot(axis)
+  local cross = axis:cross(self)
+
+  self.x = self.x * cosa + axis.x * ((1 - cosa) * dot) + cross.x * sina
+  self.y = self.y * cosa + axis.y * ((1 - cosa) * dot) + cross.y * sina
+  self.z = self.z * cosa + axis.z * ((1 - cosa) * dot) + cross.z * sina
+
+  return self
 end
 
 ---Returns a copy of this vector.
@@ -293,12 +309,18 @@ function Vector3:horizontal()
 end
 ---- CONSTANTS
 
+---@type Vector3
 Vector3.UP = Vector3(0, 1, 0)
-Vector3.DOWN = -Vector3.UP
+---@type Vector3
+Vector3.DOWN = Vector3(0, -1, 0)
+---@type Vector3
 Vector3.FORWARD = Vector3(0, 0, -1)
-Vector3.BACK = -Vector3.FORWARD
+---@type Vector3
+Vector3.BACK = Vector3(0, 0, 1)
+---@type Vector3
 Vector3.RIGHT = Vector3(1, 0, 0)
-Vector3.LEFT = -Vector3.RIGHT
+---@type Vector3
+Vector3.LEFT = Vector3(-1, 0, 0)
 
 -------------------
 return Vector3