beginning of orbital mechanics

src/main.lua

@@ -83,13 +83,13 @@ local ore_types = { "iron ore", "copper ore", "warp fuel", }
 --        the "zero relative velocity" key will be a burn whatever amount of fuel/acceleration necessary to match local acceleration
 --         which.. since the currently stored velocity is a COMPLETELY SEPARATE SYSTEM - is literally just zeroing velocity which makes it even simpler to execute
 local player_ship = {
-  position_x = screen_width / 2,
-  position_y = screen_height / 2,
+  position_x = 100,
+  position_y = 100,
   velocity_x = 0,
   velocity_y = 0,
   acceleration = 100,
 
-  radar_size = 10,
+  radar_size = 4,
 
   cargo_max_space = 100,
   cargo_free_space = 75,
@@ -103,42 +103,54 @@ local player_ship = {
 }
 
 local resource_points = {} -- NOTE they're "planets" but I intend for them to be multiple things tbh
+local function make_resource_point(x, y)
+  local current_point = {
+    position_x = x or math.random() * screen_width / 2,
+    position_y = y or math.random() * screen_height / 2,
+    radar_size = 7,
+
+    cargo_max_space = 100000,
+    cargo_free_space = 100000,
+    cargo_contents = {},
+  }
+  -- TODO exclude orbits that would collide
+  current_point.orbital_radius = math.sqrt(current_point.position_x^2 + current_point.position_y^2)
+  current_point.rotation_offset = math.atan2(current_point.position_y, current_point.position_x)
+
+  -- NOTE can select literally anything
+  local selected_type = ore_types[math.random(#ore_types)]
+  local cargo_amount = math.random() * 10000
+  transfer_cargo(nil, current_point, selected_type, cargo_amount)
+
+  local closest_object, distance_squared_to_object = get_closest_object(resource_points, current_point)
+  if closest_object and distance_squared_to_object <= (closest_object.radar_size^2 + current_point.radar_size^2) * 1.5 then
+    return
+  end
+
+  table.insert(resource_points, current_point)
+  return true
+end
+
 local function add_resource_points(point_count)
   for i = 1, point_count do
-    local function make_resource_point()
-      local current_point = {
-        position_x = math.random() * screen_width,
-        position_y = math.random() * screen_height,
-        radar_size = 10,
-
-        cargo_max_space = 100000,
-        cargo_free_space = 100000,
-        cargo_contents = {},
-      }
-
-      -- NOTE can select literally anything
-      local selected_type = ore_types[math.random(#ore_types)]
-      local cargo_amount = math.random() * 10000
-      transfer_cargo(nil, current_point, selected_type, cargo_amount)
-
-      local closest_object, distance_squared_to_object = get_closest_object(resource_points, current_point)
-      if closest_object and distance_squared_to_object <= (closest_object.radar_size^2 + current_point.radar_size^2) * 1.5 then
-        return
-      end
-
-      table.insert(resource_points, current_point)
-      return true
-    end
-
     if not make_resource_point() then
       i = i - 1
     end
   end
 end
-add_resource_points(math.random(5))
+add_resource_points(8)
+-- DEBUG hardcoded points to compare against (except they can still fail to spawn if something else is too close)
+make_resource_point(10, 0)
+make_resource_point(screen_width / 2 - 10, 0)
 
 local last_message = ""
+local game_time = 0
+-- local orbital_speed_constant = 1 -- ironically, I think 1 is exactly the speed I want
+local orbital_speed_constant = 50
+
 function love.update(dt)
+  game_time = game_time + dt
+
   -- NOTE this control scheme makes diagonal travel faster than horizontal/vertical
   if love.keyboard.isDown("w") or love.keyboard.isDown("up") then
     player_ship.velocity_y = player_ship.velocity_y - player_ship.acceleration * dt
@@ -171,6 +183,19 @@ function love.update(dt)
   player_ship.position_x = player_ship.position_x + player_ship.velocity_x * dt
   player_ship.position_y = player_ship.position_y + player_ship.velocity_y * dt
 
+  local player_radius = math.sqrt(player_ship.position_x^2 + player_ship.position_y^2)
+  local player_rotation_offset = math.atan2(player_ship.position_y, player_ship.position_x)
+  local x, y = math.cos(dt / player_radius / (1 / orbital_speed_constant) + player_rotation_offset), math.sin(dt / player_radius / (1 / orbital_speed_constant) + player_rotation_offset)
+  player_ship.position_x = x * player_radius
+  player_ship.position_y = y * player_radius
+
+  for i = 1, #resource_points do
+    local current_point = resource_points[i]
+    local x, y = math.cos(game_time / current_point.orbital_radius / (1 / orbital_speed_constant) + current_point.rotation_offset), math.sin(game_time / current_point.orbital_radius / (1 / orbital_speed_constant) + current_point.rotation_offset)
+    current_point.position_x = x * current_point.orbital_radius
+    current_point.position_y = y * current_point.orbital_radius
+  end
+
   -- TODO make this toggleable instead of requiring holding a key
   if love.keyboard.isDown("space") then
     local function collect_resource()
@@ -208,13 +233,20 @@ local font_height = font:getHeight()
 function love.draw()
   love.graphics.setColor(1, 1, 1, 1)
 
+  -- local camera_offset = {
+  --   x = screen_width / 2 - player_ship.position_x,
+  --   y = screen_height / 2 - player_ship.position_y,
+  -- }
+  local camera_offset = { x = screen_width / 2, y = screen_height / 2, }
+  love.graphics.translate(camera_offset.x, camera_offset.y)
   love.graphics.rectangle("line", player_ship.position_x - player_ship.radar_size / 2, player_ship.position_y - player_ship.radar_size / 2, player_ship.radar_size, player_ship.radar_size)
 
   for i = 1, #resource_points do
-    local resource_point = resource_points[i]
-    love.graphics.circle("line", resource_point.position_x, resource_point.position_y, resource_point.radar_size)
+    local current_point = resource_points[i]
+    love.graphics.circle("line", current_point.position_x, current_point.position_y, current_point.radar_size)
   end
 
+  love.graphics.translate(-camera_offset.x, -camera_offset.y)
   love.graphics.print(last_message, 1, 1)
 
   local inventory_status = {}