From 5e6a9b628c4261c61ae46963aaa2a8879775bc6a Mon Sep 17 00:00:00 2001
From: Klemen Plestenjak <plestenjak.klemen@gmail.com>
Date: Mon, 15 Jan 2024 11:34:49 +0100
Subject: [PATCH] Use stack alloc for sorting draw data

---
 game/game_state.h |  1 -
 game/main.c       | 18 ++++++++----------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/game/game_state.h b/game/game_state.h
index fe52585..e96ce34 100644
--- a/game/game_state.h
+++ b/game/game_state.h
@@ -82,7 +82,6 @@ typedef struct Game {
     f32 elapsed;
 
     ecs_query_t *drawQuery;
-    DrawData   *drawData;
 } Game;
 
 static void setScreen(Game *game, GameScreen newScreen) {
diff --git a/game/main.c b/game/main.c
index a46fedb..a3a821c 100644
--- a/game/main.c
+++ b/game/main.c
@@ -107,7 +107,6 @@ bool init(void *userData) {
     Game *game = ecs_singleton_get_mut(ECS, Game);
     setScreen(game, SCREEN_MAIN_MENU);
     game->font = LoadFontEx("assets/fonts/CompassPro.ttf", 92, NULL, 0);
-    game->drawData = bzArrayCreate(DrawData, 1000);
     game->drawQuery = ecs_query(ECS, {
         .filter.terms = {
                 { ecs_id(Position) },
@@ -291,8 +290,6 @@ void deinit(void *userData) {
     bzObjectPoolDestroy(game->pools.btNode);
     bzObjectPoolDestroy(game->pools.btNodeState);
 
-    bzArrayDestroy(game->drawData);
-
     soundsUnloadAll(sounds);
 
     bzUIDestroy(UI);
@@ -316,7 +313,6 @@ void update(float dt, void *userData) {
     if (game->screen != game->nextScreen)
         game->screen = game->nextScreen;
 
-    BZ_ASSERT(game->stackAlloc.allocated == 0);
     bzStackAllocReset(&game->stackAlloc);
 
     ImGuiIO *io = igGetIO();
@@ -358,9 +354,11 @@ static void renderGame(Game *game, float dt) {
     // Ground UI
     drawPlayerInputUIGround();
     // Entities
-    bzArrayClear(game->drawData);
+    i32 numDraws = ecs_query_entity_count(game->drawQuery);
+    DrawData *drawData = bzStackAlloc(&game->stackAlloc, numDraws * sizeof(*drawData));
     ecs_iter_t it = ecs_query_iter(ECS, game->drawQuery);
     ecs_entity_t worker = 0;
+    i32 drawIdx = 0;
     while (ecs_iter_next(&it)) {
         Position *p = ecs_field(&it, Position, 1);
         Size *s = ecs_field(&it, Size, 2);
@@ -382,19 +380,19 @@ static void renderGame(Game *game, float dt) {
             src.height -= 0.02f;
             if (t[i].flipX) src.width *= -1.0f;
             if (t[i].flipY) src.height *= -1.0f;
-            bzArrayPush(game->drawData, (DrawData) {
+            drawData[drawIdx++] = (DrawData) {
                 .tex = t[i].texture,
                 .src = src,
                 .dst = dst,
                 .origin = origin,
                 .rotation = r[i]
-            });
+            };
         }
     }
-    qsort(game->drawData, bzArraySize(game->drawData), sizeof(*game->drawData), cmpDrawData);
+    qsort(drawData, numDraws, sizeof(*drawData), cmpDrawData);
 
-    for (i32 i = 0; i < bzArraySize(game->drawData); i++) {
-        DrawData draw = game->drawData[i];
+    for (i32 i = 0; i < numDraws; i++) {
+        DrawData draw = drawData[i];
         DrawTexturePro(draw.tex, draw.src, draw.dst, draw.origin, draw.rotation, WHITE);
     }
     Vector2 target = GetMousePosition();