weapon attachment to parent

src/entity.c

@@ -265,6 +265,7 @@ struct xform entity_get_local_xform(struct entity *ent)
 
 void entity_set_xform(struct entity *ent, struct xform xf)
 {
+    if (!xform_eq(xf, ent->cached_global_xform)) {
         struct entity_store *store = entity_get_store(ent);
         /* Update local xform */
         if (ent->is_top) {
@@ -277,13 +278,16 @@ void entity_set_xform(struct entity *ent, struct xform xf)
         ent->cached_global_xform = xf;
         ent->cached_global_xform_dirty = false;
         entity_mark_child_xforms_dirty(store, ent);
+    }
 }
 
 void entity_set_local_xform(struct entity *ent, struct xform xf)
 {
+    if (!xform_eq(xf, ent->local_xform)) {
         ent->local_xform = xf;
         ent->cached_global_xform_dirty = true;
         entity_mark_child_xforms_dirty(entity_get_store(ent), ent);
+    }
 }
 
 /* ========================== *

src/entity.h

@@ -24,6 +24,8 @@ enum entity_prop {
 
     ENTITY_PROP_BULLET,
 
+    ENTITY_PROP_ATTACHED,
+
     /* Test props */
 
     ENTITY_PROP_TEST,
@@ -122,6 +124,13 @@ struct entity {
     f64 animation_time_in_frame;
     u32 animation_frame;
 
+    /* ====================================================================== */
+    /* Attachment */
+
+    /* ENTITY_PROP_ATTACHED */
+    /* Slice name on the parent entity's sprite to attach to */
+    struct string attach_slice;
+
     /* ====================================================================== */
     /* Equip */
 

src/game.c

@@ -118,9 +118,9 @@ INTERNAL void spawn_test_entities(void)
         entity_set_xform(e, xf);
 
         e->sprite = sprite_tag_from_path(STR("res/graphics/tim.ase"));
-        e->sprite_span_name = STR("idle.unarmed");
+        //e->sprite_span_name = STR("idle.unarmed");
         //e->sprite_span_name = STR("idle.one_handed");
-        //e->sprite_span_name = STR("idle.two_handed");
+        e->sprite_span_name = STR("idle.two_handed");
 
         entity_enable_prop(e, ENTITY_PROP_PLAYER_CONTROLLED);
         e->player_max_speed = 4.f;
@@ -140,18 +140,14 @@ INTERNAL void spawn_test_entities(void)
         f32 r = PI / 4;
         struct entity *e = entity_alloc(root);
 #else
-        struct v2 pos = V2(0.1, 0);
-        struct v2 size = V2(1, 1);
-        f32 r = 0;
         struct entity *e = entity_alloc(player_ent);
 #endif
 
-
-        struct xform xf = XFORM_TRS(.t = pos, .r = r, .s = size);
-        entity_set_local_xform(e, xf);
-
         e->sprite = sprite_tag_from_path(STR("res/graphics/gun.ase"));
 
+        entity_enable_prop(e, ENTITY_PROP_ATTACHED);
+        e->attach_slice = STR("attach.wep");
+
         entity_enable_prop(e, ENTITY_PROP_WEAPON);
         e->trigger_delay = 1.0 / 10.0;
 
@@ -284,7 +280,8 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
         if (!ent->valid) continue;
 
         if (!entity_has_prop(ent, ENTITY_PROP_ACTIVE)) {
-            if (ent->activation_tick == 0 || G.tick.tick_id >= ent->activation_tick) {
+            u64 atick = ent->activation_tick;
+            if (atick != 0 || G.tick.tick_id >= atick) {
                 entity_enable_prop(ent, ENTITY_PROP_ACTIVE);
                 ent->activation_tick = G.tick.tick_id;
                 ++ent->continuity_gen;
@@ -360,6 +357,33 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
         ent->sprite_local_xform = xf;
     }
 
+    /* ========================== *
+     * Update attachments
+     * ========================== */
+
+    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;
+
+        if (entity_has_prop(ent, ENTITY_PROP_ATTACHED)) {
+            struct entity *parent = entity_from_handle(store, ent->parent);
+            struct sprite_tag parent_sprite = parent->sprite;
+            struct sprite_sheet *parent_sheet = sprite_sheet_from_tag_await(sprite_frame_scope, parent_sprite);
+
+            struct xform parent_xf = entity_get_xform(parent);
+            struct xform parent_sprite_xf = xform_mul(parent_xf, parent->sprite_local_xform);
+
+            struct sprite_sheet_slice attach_slice = sprite_sheet_get_slice(parent_sheet, ent->attach_slice, parent->animation_frame);
+            struct v2 attach_pos = xform_mul_v2(parent_sprite_xf, attach_slice.center);
+            struct v2 attach_dir = xform_basis_mul_v2(parent_sprite_xf, attach_slice.dir);
+
+            struct xform xf = entity_get_xform(ent);
+            xf.og = attach_pos;
+            xf = xform_with_rotation(xf, v2_angle(attach_dir) + PI / 2);
+            entity_set_xform(ent, xf);
+        }
+    }
+
     /* ========================== *
      * Update control from player cmds
      * ========================== */
@@ -506,7 +530,7 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
                 bullet->bullet_src = ent->handle;
                 bullet->bullet_src_pos = rel_pos;
                 bullet->bullet_src_dir = rel_dir;
-                bullet->bullet_impulse = 25;
+                bullet->bullet_impulse = 5;
 
                 entity_enable_prop(bullet, ENTITY_PROP_BULLET);
             }
@@ -530,7 +554,7 @@ INTERNAL void game_update(struct game_cmd_array game_cmds)
             f32 final_xf_angle;
             {
                 struct sprite_sheet *sheet = sprite_sheet_from_tag_await(sprite_frame_scope, ent->sprite);
-                struct sprite_sheet_slice slice = sprite_sheet_get_slice(sheet, STR("hold"), ent->animation_frame);
+                struct sprite_sheet_slice slice = sprite_sheet_get_slice(sheet, STR("attach.wep"), ent->animation_frame);
 
                 f32 forward_hold_angle_offset;
                 {

src/math.h

@@ -741,6 +741,11 @@ INLINE struct v2 xform_get_scale(struct xform xf);
 INLINE struct trs trs_from_xform(struct xform m);
 INLINE struct trs trs_lerp(struct trs a, struct trs b, f32 t);
 
+INLINE b32 xform_eq(struct xform xf1, struct xform xf2)
+{
+    return v2_eq(xf1.bx, xf2.bx) && v2_eq(xf1.by, xf2.by) && v2_eq(xf1.og, xf2.og);
+}
+
 INLINE struct xform xform_from_pos(struct v2 v)
 {
     return (struct xform) {

src/memory.h

@@ -11,6 +11,9 @@
 #define MEMCMP_STRUCT(p1, p2) MEMCMP((p1), (p2), sizeof(*p1))
 #define MEMCMP(p1, p2, n) memcmp((p1), (p2), (n))
 
+#define MEMEQ_STRUCT(p1, p2) MEMEQ((p1), (p2), sizeof(*p1))
+#define MEMEQ(p1, p2, n) (MEMCMP((p1), (p2), (n)) == 0)
+
 #define MEMSET(ptr, val, count) memset((ptr), (val), (count))
 
 #if CRTLIB

src/sprite.c

@@ -974,6 +974,8 @@ struct sprite_sheet_slice sprite_sheet_get_slice(struct sprite_sheet *sheet, str
     /* Return 'pivot' by default */
     struct sprite_sheet_slice res = { 0 };
     if (string_eq(name, STR("pivot"))) {
+        /* 'pivot' slice does not exist, return center */
+        res.center = V2(0, 0);
         res.center_px = v2_mul(sheet->frame_size, 0.5f);
         res.dir_px = V2(res.center_px.x, 0);
         res.dir = V2(0, -0.5);
@@ -1096,10 +1098,10 @@ INTERNAL SYS_THREAD_ENTRY_POINT_FUNC_DEF(sprite_evictor_thread_entry_point, arg)
                                 }
 #endif
 
-                                /* Check usage time */
 #if RESOURCE_RELOADING
+                                /* Check usage time */
                                 /* Only check conditional if RESOURCE_RELOADING is enabled,
-                                    * since over-budget is assumed to be * true otherwise */
+                                 * since over-budget is assumed to be true otherwise */
                                 if (cache_over_budget)
 #endif
                                 {