From 9424c9c2c9ca1148daf524bb8dccac8031cca898 Mon Sep 17 00:00:00 2001
From: jacob <jacob@cagori.com>
Date: Wed, 14 Aug 2024 18:40:00 -0500
Subject: [PATCH] correct bullet starting point

---
 src/entity.h |  3 +++
 src/game.c   | 75 +++++++++++++++++++++++++---------------------------
 2 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/src/entity.h b/src/entity.h
index 7fa59ab3..9985eb8d 100644
--- a/src/entity.h
+++ b/src/entity.h
@@ -138,6 +138,9 @@ struct entity {
     /* Bullet */
 
     struct entity_handle bullet_src;
+    struct v2 bullet_src_pos;
+    struct v2 bullet_src_dir;
+    f32 bullet_impulse;
 
     /* ====================================================================== */
     /* Testing */
diff --git a/src/game.c b/src/game.c
index b809c2f5..63a3991e 100644
--- a/src/game.c
+++ b/src/game.c
@@ -156,8 +156,6 @@ INTERNAL void spawn_test_entities(void)
         e->trigger_delay = 1.0 / 10.0;
 
         player_ent->equipped = e->handle;
-
-        //entity_enable_prop(e, ENTITY_PROP_KINEMATIC);
     }
 
     /* Camera */
@@ -490,55 +488,27 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
 
         /* Fire weapon */
         if (entity_has_prop(ent, ENTITY_PROP_WEAPON)) {
-            struct xform xf = entity_get_xform(ent);
-
             struct sprite_tag sprite = ent->sprite;
             u32 animation_frame = ent->animation_frame;
-            struct xform sprite_xform = xform_mul(xf, ent->sprite_local_xform);
             struct sprite_sheet *sheet = sprite_sheet_from_tag_await(sprite_frame_scope, sprite);
 
+            struct xform sprite_local_xform = ent->sprite_local_xform;
+
             struct sprite_sheet_slice out_slice = sprite_sheet_get_slice(sheet, STR("out"), animation_frame);
-            struct v2 out_pos = xform_mul_v2(sprite_xform, out_slice.center);
-            struct v2 out_vec = xform_basis_mul_v2(sprite_xform, out_slice.dir);
-            out_vec = v2_norm(out_vec);
-            out_vec = v2_mul(out_vec, 25);
+            struct v2 rel_pos = xform_mul_v2(sprite_local_xform, out_slice.center);
+            struct v2 rel_dir = xform_basis_mul_v2(sprite_local_xform, out_slice.dir);
 
             {
-                /* FIXME: Weapon velocity should affect bullet velocity
-                 * (This should also make bullet_src_ent unnecessary for
-                 * drawing bullet trails) */
-
-#if 1
-                 /* Spawn bullet */
+                /* Spawn bullet */
                 struct entity *bullet = entity_alloc(root);
                 bullet->sprite = sprite_tag_from_path(STR("res/graphics/bullet.ase"));
-                struct xform bullet_xf = XFORM_TRS(.t = out_pos, .r = v2_angle(out_vec) + PI / 2);
-                entity_set_xform(bullet, bullet_xf);
-                bullet->velocity = out_vec;
-                bullet->bullet_src = ent->handle;
-                entity_enable_prop(bullet, ENTITY_PROP_BULLET);
-#elif 1
-                 /* TODO: Remove this (testing) */
-                 struct v2 barrel_velocity = entity_from_handle(store, ent->parent)->velocity;
 
-                 /* Create bullet */
-                 /* TODO: Move bullet infront of barrel by hitbox */
-                struct entity *bullet = entity_alloc(root);
-                bullet->sprite = sprite_tag_from_path(STR("res/graphics/bullet.ase"));
-                struct xform bullet_xf = XFORM_TRS(.t = out_pos, .r = v2_angle(out_vec) + PI / 2);
-                entity_set_xform(bullet, bullet_xf);
-                entity_enable_prop(bullet, ENTITY_PROP_BULLET);
                 bullet->bullet_src = ent->handle;
-                bullet->activation_tick = G.tick.tick_id + 1;
-                bullet->velocity = barrel_velocity;
+                bullet->bullet_src_pos = rel_pos;
+                bullet->bullet_src_dir = rel_dir;
+                bullet->bullet_impulse = 25;
 
-                /* Create impulse */
-                struct entity *impulse = entity_alloc(root);
-                entity_enable_prop(impulse, ENTITY_PROP_IMPULSE);
-                impulse->impulse_target = bullet->handle;
-                impulse->impulse_vec = out_vec;
-                impulse->activation_tick = bullet->activation_tick + 1;  /* Ensure bullet exists for 1 tick at the start of the barrel before impulse is applied */
-#endif
+                entity_enable_prop(bullet, ENTITY_PROP_BULLET);
             }
         }
     }
@@ -633,6 +603,33 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
         }
     }
 
+    /* ========================== *
+     * Initialize bullet kinematics from sources
+     * ========================== */
+
+    for (u64 entity_index = 0; entity_index < store->reserved; ++entity_index) {
+        struct entity *ent = &store->entities[entity_index];
+        if (!(ent->valid && entity_has_prop(ent, ENTITY_PROP_ACTIVE))) continue;
+
+        /* FIXME: Apply src entity velocity to bullet velocity */
+
+        if (entity_has_prop(ent, ENTITY_PROP_BULLET) && !entity_has_prop(ent, ENTITY_PROP_KINEMATIC)) {
+            struct entity *src = entity_from_handle(store, ent->bullet_src);
+            struct xform src_xf = entity_get_xform(src);
+
+            struct v2 pos = xform_mul_v2(src_xf, ent->bullet_src_pos);
+            struct v2 vec = xform_basis_mul_v2(src_xf, ent->bullet_src_dir);
+            vec = v2_mul(v2_norm(vec), ent->bullet_impulse);
+
+            struct xform xf = XFORM_TRS(.t = pos, .r = v2_angle(vec) + PI / 2);
+            entity_set_xform(ent, xf);
+
+            ent->velocity = vec;
+
+            entity_enable_prop(ent, ENTITY_PROP_KINEMATIC);
+        }
+    }
+
     /* ========================== *
      * Update camera position
      * ========================== */