From 5bcf22a6f8dce820f0d978703ae6bc74a75b233f Mon Sep 17 00:00:00 2001
From: Donald Ball <donald.ball@gmail.com>
Date: Mon, 17 Nov 2025 20:31:14 -0500
Subject: [PATCH] bullet recoil, use tau

---
 asteroids/main.lua | 15 +++++++--------
 asteroids/phys.lua |  6 +-----
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/asteroids/main.lua b/asteroids/main.lua
index cb45bbf..1f50818 100644
--- a/asteroids/main.lua
+++ b/asteroids/main.lua
@@ -10,7 +10,7 @@ local function initGame()
             radius = 30,
             bullet = {
                 radius = 5,
-                recoil = -10,
+                recoil = 10,
                 speed = 500,
                 time = 4,
                 sound = love.sound.newSoundData('resources/bullet.mp3'),
@@ -104,7 +104,7 @@ function love.update(dt)
         end
 
         local spin = state.controls.joystick:getGamepadAxis('leftx') * game.controls.ship.turnRate
-        state.ship.facing = (state.ship.facing + spin * dt) % phys.tau
+        state.ship.facing = (state.ship.facing + spin * dt)
     end
     update(state.ship, dt)
 
@@ -121,8 +121,8 @@ function love.update(dt)
             if phys.intersects(bullet, asteroid) then
                 table.remove(state.bullets, bulletIndex)
                 if asteroid.stage > 1 then
-                    local angle1 = love.math.random() * (2 * math.pi)
-                    local angle2 = (angle1 - math.pi) % (2 * math.pi)
+                    local angle1 = love.math.random() * phys.tau
+                    local angle2 = angle1 - phys.tau / 2
                     local radius = game.asteroids.stages[asteroid.stage - 1].radius
                     local speed = game.asteroids.stages[asteroid.stage - 1].speed
                     table.insert(state.asteroids, {
@@ -158,7 +158,7 @@ function love.update(dt)
     end
 
     if #state.asteroids == 0 then
-        --reset()
+        reset()
     end
 end
 
@@ -180,8 +180,7 @@ function love.gamepadpressed(joystick, button)
         }
         table.insert(state.bullets, bullet)
         bullet.sound:play()
-        --state.ship.speed.x = state.ship.speed.x + math.cos(state.ship.angle) * game.ship.bullet.recoil
-        --state.ship.speed.y = state.ship.speed.y + math.sin(state.ship.angle) * game.ship.bullet.recoil
+        phys.apply(state.ship, { speed = game.ship.bullet.recoil, angle = state.ship.facing + phys.tau / 2 })
     end
     if button == "x" then
         print(inspect(state.ship))
@@ -198,7 +197,7 @@ function love.draw()
             love.graphics.draw(game.ship.sprite,
                 state.ship.x,
                 state.ship.y,
-                (state.ship.facing + math.pi / 2) % (math.pi * 2),
+                (state.ship.facing + phys.tau / 4) % phys.tau,
                 scale,
                 scale,
                 game.ship.sprite:getWidth() / 2,
diff --git a/asteroids/phys.lua b/asteroids/phys.lua
index b850788..3772423 100644
--- a/asteroids/phys.lua
+++ b/asteroids/phys.lua
@@ -18,10 +18,6 @@ function phys.update(actor, dt)
     actor.y = actor.y + math.sin(actor.angle) * dv
 end
 
-function phys.rotate(actor, angle)
-    actor.facing = (actor.facing + angle) % phys.tau
-end
-
 function phys.apply(actor, force)
     local ax = math.cos(actor.angle) * actor.speed
     local ay = math.sin(actor.angle) * actor.speed
@@ -31,7 +27,7 @@ function phys.apply(actor, force)
     local y = ay + fy
 
     local speed = math.sqrt(x ^ 2 + y ^ 2)
-    local angle = math.atan2(y, x) % phys.tau
+    local angle = math.atan2(y, x)
     actor.speed = speed
     actor.angle = angle
 end