From beec7c23cdd1e302093acf38001f5c29fb1c1b70 Mon Sep 17 00:00:00 2001
From: Jason Hilder <jhilder95@gmail.com>
Date: Mon, 3 Aug 2026 06:40:17 +0200
Subject: [PATCH] Setup basic enemy information and make enemy use flow field.

---
 src/enemy.odin | 59 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

diff --git a/src/enemy.odin b/src/enemy.odin
index 9a62357..1d6f318 100644
--- a/src/enemy.odin
+++ b/src/enemy.odin
@@ -16,7 +16,9 @@ Enemy :: struct {
 
     // movement
 	velocity:		  rl.Vector2,
-	speed:			  f32, 
+	speed:			  f32, // max move speed
+	accel:			  f32, // how fast to reach speed
+	friction:		  f32, // how fast to stop
 
     // collision
 	collider_offset:  rl.Vector2,
@@ -27,10 +29,14 @@ Enemy :: struct {
 enemy_init :: proc(assets: ^Enemy_Assets, pos: [2]f32) -> Enemy {
 	enemy := Enemy{}
 	enemy.position = {pos.x, pos.y}
+	enemy.speed = 100
+	enemy.accel = 720
+	enemy.friction = 640
+
     enemy.state = .IDLE
 	enemy.collider_offset = rl.Vector2{8, 15}
-	enemy.collider_w = 16
-	enemy.collider_h = 10
+	enemy.collider_w = 12
+	enemy.collider_h = 8
     animation_play(&enemy.animation, &assets.clips[.IDLE])
 
 	return enemy
@@ -45,6 +51,13 @@ get_enemy_collider :: proc(enemy: Enemy, pos: rl.Vector2) -> rl.Rectangle {
 	}
 }
 
+get_enemy_center :: proc(enemy: Enemy, pos: rl.Vector2) -> rl.Vector2 {
+    collider := get_enemy_collider(enemy, pos)
+    return rl.Vector2{
+        collider.x + collider.width * 0.5,
+        collider.y + collider.height * 0.5,
+    }
+}
 
 get_spawn_rect :: proc(max_x, max_y: f32) -> rl.Rectangle {
     enemy_spawn_points: [4]rl.Rectangle = {
@@ -63,6 +76,7 @@ get_spawn_rect :: proc(max_x, max_y: f32) -> rl.Rectangle {
     return rand_pos
 }
 
+
 // @TODO consider a self check, ie pass the enemy in question index and make sure to skip that
 spawn_enemy :: proc(enemy_array: ^[MAX_ENEMIES]Enemy, assets: ^Enemy_Assets, enemy_count: ^int, game_map: Game_Map) {
     max_x := game_map.width_px
@@ -91,10 +105,47 @@ spawn_enemy :: proc(enemy_array: ^[MAX_ENEMIES]Enemy, assets: ^Enemy_Assets, ene
     }
 }
 
-update_enemies :: proc(enemy_array: ^[MAX_ENEMIES]Enemy, assets: ^Enemy_Assets, enemy_cnt: int, dt: f32) {
+update_enemies :: proc(enemy_array: ^[MAX_ENEMIES]Enemy, assets: ^Enemy_Assets, enemy_cnt: int, game_map: Game_Map, dt: f32) {
     for idx in 0..<enemy_cnt {
         enemy := &enemy_array[idx]
         moving := false
+        dir := rl.Vector2{}
+
+        enemy_center     := get_enemy_center(enemy^, enemy.position)
+        enemy_grid_pos   := world_to_grid(enemy_center)
+        enemy_grid_index := grid_to_index(enemy_grid_pos.x, enemy_grid_pos.y, game_map.width)
+
+        // already normalized
+        flow_dir := game_map.flow_field[enemy_grid_index]
+
+        // wall avoidance steering
+
+        target_velocity := flow_dir * enemy.speed
+
+        enemy.velocity = rl.Vector2MoveTowards(enemy.velocity, target_velocity, enemy.accel * dt)
+        // Check for collisions
+        new_position := enemy.velocity * dt
+        new_x_pos := rl.Vector2{enemy.position.x + new_position.x, enemy.position.y}
+        if
+        !check_map_collision(get_enemy_collider(enemy^, new_x_pos), game_map)
+        {
+            enemy.position.x = new_x_pos.x
+            moving = true
+        } else {
+            enemy.velocity.x = 0
+            moving = false
+        }
+
+        new_y_pos := rl.Vector2{enemy.position.x, enemy.position.y + new_position.y}
+        if
+        !check_map_collision(get_enemy_collider(enemy^, new_y_pos), game_map)
+        {
+            enemy.position.y = new_y_pos.y
+            moving = true
+        } else {
+            enemy.velocity.y = 0
+            moving = false
+        }
 
         enemy.state = moving ? .WALK : .IDLE
         animation_play(&enemy.animation, &assets.clips[enemy.state])