From f1e8cfc70fd6c2d4a1b67d8cf2ecdefb65206fe9 Mon Sep 17 00:00:00 2001
From: quou <quou@disroot.org>
Date: Mon, 10 Mar 2025 14:08:57 +1100
Subject: sort the forward drawlist front-to-back

---
 c2.cpp       |  2 +-
 model.cpp    |  1 +
 model.hpp    |  1 +
 renderer.cpp | 19 +++++++++++++++++++
 renderer.hpp |  1 +
 5 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/c2.cpp b/c2.cpp
index 94e2e38..1262241 100644
--- a/c2.cpp
+++ b/c2.cpp
@@ -21,7 +21,7 @@ extern "C" {
 #define video_arena_size (1024 * 1024 * 16)
 #define asset_arena_size (1024 * 1024 * 4)
 #define ui_arena_size    (1024 * 1024)
-#define scene_arena_size (1024 * 4)
+#define scene_arena_size (1024 * 8)
 #define per_frame_memory_size (1024 * 1024)
 
 #define MSAA_SAMPLES 4
diff --git a/model.cpp b/model.cpp
index cb9c23e..6aba19e 100644
--- a/model.cpp
+++ b/model.cpp
@@ -308,6 +308,7 @@ void Model_Instance::update() {
 		);
 		bound.encompass(bounds[i]);
 	}
+	centre = bound.min + bound.max * 0.5f;
 }
 
 void Model_Instance::update_cbuffers(Device* dev) {
diff --git a/model.hpp b/model.hpp
index 7417e51..75e310e 100644
--- a/model.hpp
+++ b/model.hpp
@@ -110,6 +110,7 @@ struct Model_Instance {
 	Model* m;
 	AABB* bounds;
 	AABB bound;
+	v3f centre;
 
 	void init(Device* dev, Heap* h, Model* model);
 	void destroy(Device* dev, Heap* h);
diff --git a/renderer.cpp b/renderer.cpp
index c7040ec..64c3795 100644
--- a/renderer.cpp
+++ b/renderer.cpp
@@ -5,6 +5,8 @@ extern "C" {
 #include "memory.h"
 }
 
+#include <algorithm>
+
 struct VP_Cbuffer {
 	m4f view_projection;
 };
@@ -91,6 +93,21 @@ void Drawlist::render(
 	}
 }
 
+void Drawlist::sort(const Renderer& r) {
+	const Camera& cam = r.get_camera(camera);
+	v3f far = cam.position + cam.far * cam.forward;
+	/* ideally want to sort the meshes within each model as
+	 * well but as long as the models are small it wont matter
+	 * too much... */
+	std::sort(
+		models,
+		models + count,
+		[&far](const Model_Instance* a, const Model_Instance* b) {
+			return v3f::dot(a->centre, far) < v3f::dot(b->centre, far);
+		}
+	);
+}
+
 void Renderer::update_globals(
 	const Lighting* l,
 	Device* d,
@@ -136,6 +153,8 @@ void Renderer::render(
 			.build_rp();
 	}
 
+	drawlists[FORWARD].sort(*this);
+
 	ctx.debug_push("depth prepass");
 	drawlists[FORWARD].render(*this, dev, a, l, depth_prepass, 0);
 	ctx.debug_pop();
diff --git a/renderer.hpp b/renderer.hpp
index 6bfe551..a76afa9 100644
--- a/renderer.hpp
+++ b/renderer.hpp
@@ -30,6 +30,7 @@ struct Drawlist {
 		Render_Pass& pass,
 		void (*overrider)(Pipeline_Builder&)
 	);
+	void sort(const Renderer& r);
 };
 
 struct Renderer {
-- 
cgit v1.2.3-54-g00ecf