From 523fe0f2b1092fabc91424893d60b14557aa9cf8 Mon Sep 17 00:00:00 2001
From: Doyle Thai <dyl.thai@gmail.com>
Date: Thu, 4 Aug 2016 00:48:43 +1000
Subject: [PATCH] Introduce notion of attack spec for battles

An attack spec will be used to hold the stats of both the attacker and
defender, grouping the data necessary to determine how much damage the
defender takes and other statuses caused by the attack.
---
 src/WorldTraveller.c | 44 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/src/WorldTraveller.c b/src/WorldTraveller.c
index c5dfcf5..fe04af2 100644
--- a/src/WorldTraveller.c
+++ b/src/WorldTraveller.c
@@ -729,6 +729,13 @@ INTERNAL void entityStateSwitch(EventQueue *eventQueue, World *world,
 	entity->state = newState;
 }
 
+typedef struct AttackSpec
+{
+	Entity *attacker;
+	Entity *defender;
+	i32 damage;
+} AttackSpec;
+
 INTERNAL void beginAttack(EventQueue *eventQueue, World *world,
                           Entity *attacker)
 {
@@ -759,14 +766,16 @@ INTERNAL void beginAttack(EventQueue *eventQueue, World *world,
 	}
 }
 
-INTERNAL void endAttack(EventQueue *eventQueue, World *world, Entity *attacker)
+// TODO(doyle): MemArena here is temporary until we incorporate AttackSpec to
+// battle in general!
+INTERNAL void endAttack(MemoryArena *arena, EventQueue *eventQueue,
+                        World *world, Entity *attacker)
 {
 #ifdef DENGINE_DEBUG
 	ASSERT(attacker->stats->entityIdToAttack != ENTITY_NULL_ID);
 #endif
 
 	entityStateSwitch(eventQueue, world, attacker, entitystate_battle);
-	registerEvent(eventQueue, eventtype_end_attack, attacker);
 	switch (attacker->stats->queuedAttack)
 	{
 	case entityattack_tackle:
@@ -821,6 +830,13 @@ INTERNAL void endAttack(EventQueue *eventQueue, World *world, Entity *attacker)
 	if (!noMoreValidTargets)
 	{
 		i32 damage = 50;
+
+		AttackSpec *attackSpec = PLATFORM_MEM_ALLOC(arena, 1, AttackSpec);
+		attackSpec->attacker   = attacker;
+		attackSpec->defender   = defender;
+		attackSpec->damage     = damage;
+
+		registerEvent(eventQueue, eventtype_end_attack, attackSpec);
 		// TODO(doyle): Use attacker stats in battle equations
 		if (attacker->type == entitytype_hero)
 		{
@@ -1000,7 +1016,7 @@ void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 				if (stats->busyDuration <= 0)
 				{
 					/* Apply attack damage */
-					endAttack(&eventQueue, world, entity);
+					endAttack(&state->arena, &eventQueue, world, entity);
 				}
 			}
 		}
@@ -1035,10 +1051,28 @@ void worldTraveller_gameUpdateAndRender(GameState *state, f32 dt)
 			{
 				if (!event.data) continue;
 
-				Entity *entity = (CAST(Entity *) event.data);
+				AttackSpec *attackSpec = (CAST(AttackSpec *)event.data);
+				Entity *attacker = attackSpec->attacker;
+				Entity *defender = attackSpec->defender;
+
 			    audio_playVorbis(
-			        arena, audioManager, entity->audioRenderer,
+			        arena, audioManager, attacker->audioRenderer,
 			        asset_getVorbis(assetManager, audiolist_tackle), 1);
+
+				char damageStr[12];
+			    common_itoa(attackSpec->damage, damageStr,
+			                ARRAY_COUNT(damageStr));
+
+			    // TODO(doyle): Incorporate UI into entity list or it's own list
+			    // with a rendering lifetime value
+			    renderer_string(renderer, &state->arena,
+			                    cameraBounds, font,
+			                    damageStr, defender->pos, V2(0, 0),
+			                    0, V4(1, 1, 1, 1));
+
+			    PLATFORM_MEM_FREE(&state->arena, attackSpec,
+			                      sizeof(AttackSpec));
+
 			    break;
 		    }
 			// NOTE(doyle): We delete dead entities at the end of the update