From 657b590b6fc57bcfbefaf5db27714a5b1920269e Mon Sep 17 00:00:00 2001
From: asrael <asrael@pxl8.org>
Date: Sat, 7 Feb 2026 20:08:22 -0600
Subject: [PATCH] wire up pipeline cache

---
 src/core/pxl8.c       |  1 +
 src/gfx/pxl8_render.c | 53 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/src/core/pxl8.c b/src/core/pxl8.c
index 758efb8..1895703 100644
--- a/src/core/pxl8.c
+++ b/src/core/pxl8.c
@@ -283,6 +283,7 @@ pxl8_result pxl8_init(pxl8* sys, i32 argc, char* argv[]) {
     }
 
 #ifndef NDEBUG
+    game->debug_stats = true;
     game->debug_replay = pxl8_replay_create_buffer(60, 60);
     pxl8_sfx_mixer_set_event_callback(game->mixer, pxl8_audio_event_callback, game);
 #endif
diff --git a/src/gfx/pxl8_render.c b/src/gfx/pxl8_render.c
index 76417e7..2ecf566 100644
--- a/src/gfx/pxl8_render.c
+++ b/src/gfx/pxl8_render.c
@@ -734,6 +734,27 @@ typedef struct {
     bool valid;
 } pipeline_cache_entry;
 
+static u32 pipeline_desc_hash(const pxl8_gfx_pipeline_desc* d) {
+    u32 h = 2166136261u;
+    h = (h ^ (u32)d->blend.enabled) * 16777619u;
+    h = (h ^ (u32)d->blend.src) * 16777619u;
+    h = (h ^ (u32)d->blend.dst) * 16777619u;
+    h = (h ^ (u32)d->blend.alpha_test) * 16777619u;
+    h = (h ^ (u32)d->blend.alpha_ref) * 16777619u;
+    h = (h ^ (u32)d->depth.test) * 16777619u;
+    h = (h ^ (u32)d->depth.write) * 16777619u;
+    h = (h ^ (u32)d->depth.compare) * 16777619u;
+    h = (h ^ (u32)d->dither) * 16777619u;
+    h = (h ^ (u32)d->double_sided) * 16777619u;
+    h = (h ^ (u32)d->emissive) * 16777619u;
+    h = (h ^ (u32)d->rasterizer.cull) * 16777619u;
+    h = (h ^ (u32)d->rasterizer.fill) * 16777619u;
+    u64 s = (u64)(uintptr_t)d->shader;
+    h = (h ^ (u32)s) * 16777619u;
+    h = (h ^ (u32)(s >> 32)) * 16777619u;
+    return h;
+}
+
 typedef struct {
     pxl8_gfx_pipeline_desc desc;
     u16 generation;
@@ -900,12 +921,39 @@ pxl8_gfx_buffer pxl8_create_buffer(pxl8_renderer* r, const pxl8_gfx_buffer_desc*
 }
 
 pxl8_gfx_pipeline pxl8_create_pipeline(pxl8_renderer* r, const pxl8_gfx_pipeline_desc* desc) {
+    u32 hash = pipeline_desc_hash(desc);
+    u32 bucket = hash & (PXL8_PIPELINE_CACHE_SIZE - 1);
+    pipeline_cache_entry* ce = &r->pipeline_cache[bucket];
+
+    if (ce->valid && ce->hash == hash) {
+        pipeline_slot* s = &r->pipelines[ce->slot_idx];
+        if (s->active && s->cached) {
+            ce->last_used_frame = r->frame_counter;
+            return (pxl8_gfx_pipeline){ MAKE_ID(ce->slot_idx, s->generation) };
+        }
+    }
+
     for (u32 i = 0; i < PXL8_GFX_MAX_PIPELINES; i++) {
         if (!r->pipelines[i].active) {
             pipeline_slot* s = &r->pipelines[i];
             s->desc = *desc;
             s->generation = NEXT_GEN(s->generation);
             s->active = true;
+
+            if (!ce->valid || ce->last_used_frame != r->frame_counter) {
+                if (ce->valid && ce->slot_idx < PXL8_GFX_MAX_PIPELINES) {
+                    r->pipelines[ce->slot_idx].cached = false;
+                    r->pipelines[ce->slot_idx].active = false;
+                }
+                s->cached = true;
+                ce->hash = hash;
+                ce->slot_idx = i;
+                ce->last_used_frame = r->frame_counter;
+                ce->valid = true;
+            } else {
+                s->cached = false;
+            }
+
             return (pxl8_gfx_pipeline){ MAKE_ID(i, s->generation) };
         }
     }
@@ -980,7 +1028,8 @@ void pxl8_destroy_buffer(pxl8_renderer* r, pxl8_gfx_buffer buf) {
 void pxl8_destroy_pipeline(pxl8_renderer* r, pxl8_gfx_pipeline pip) {
     u32 idx = SLOT_INDEX(pip.id);
     if (idx < PXL8_GFX_MAX_PIPELINES && r->pipelines[idx].generation == SLOT_GEN(pip.id)) {
-        r->pipelines[idx].active = false;
+        if (!r->pipelines[idx].cached)
+            r->pipelines[idx].active = false;
     }
 }
 
@@ -1415,6 +1464,8 @@ void pxl8_gfx_submit(pxl8_renderer* r, pxl8_gfx_cmdbuf* cb) {
             r->buffers[i].append_pos = 0;
         }
     }
+
+    r->frame_counter++;
 }
 
 void pxl8_clear(pxl8_renderer* r, pxl8_gfx_texture target, u8 color) {