From 3dab7a77c5799682bdf0517771a45ffd7a4f33ad Mon Sep 17 00:00:00 2001
From: Eltrac <hi@guhub.cn>
Date: Fri, 14 Mar 2025 16:02:40 +0800
Subject: feat: player gets knocked back getting hit by enemy

---
 config.lua         |  6 +++++-
 objects/Player.lua | 11 ++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/config.lua b/config.lua
index 22d06d2..2e95283 100644
--- a/config.lua
+++ b/config.lua
@@ -28,6 +28,7 @@ config = {
     playerShootCooldown = 0.2,
 
     player = {
+        size = 20,
         punch = {
             radius = 15,
             angle = 120,
@@ -36,7 +37,10 @@ config = {
             damageCoefficient = 10,
             cooldown = 0.5
         },
-        size = 20,
+        knockback = {
+            force = 200,
+            duration = 0.2
+        },
     },
 
     wave = {
diff --git a/objects/Player.lua b/objects/Player.lua
index 09f3a58..d515a5f 100644
--- a/objects/Player.lua
+++ b/objects/Player.lua
@@ -40,7 +40,7 @@ function Player:setY(y)
 end
 
 function Player:move(v)
-    if self.dashing and self.dashing >= G.time then return end
+    if self.knocked and self.knocked >= G.time then return end
     self.moving = (v.x ~= 0 or v.y ~= 0)
     self.physicsBody:setLinearVelocity(v.x, v.y)
 end
@@ -148,6 +148,15 @@ function Player:onContact(other, contact)
         if not (other.stunned or self:isShielded()) then
             audio.play("getsHit")
             table.remove(self.hearts)
+            -- knock back Player
+            local ex, ey = other.x, other.y
+            local dx, dy = self.x - ex, self.y - ey
+            local distance = math.sqrt(dx * dx + dy * dy)
+            local normEdx, normEdy = dx / distance, dy / distance
+            local knockbackX, knockbackY = normEdx * config.player.knockback.force,
+                normEdy * config.player.knockback.force
+            self.knocked = G.time + config.player.knockback.duration
+            self.physicsBody:applyLinearImpulse(knockbackX, knockbackY)
             -- shield this player
             self.shieldedTill = G.time + config.playerShieldTime
         end
-- 
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