From 169f068f75a5e4cd65cb2615ac4100cb4c775324 Mon Sep 17 00:00:00 2001
From: Thinkofname <thinkofdeath@spigotmc.org>
Date: Tue, 22 Mar 2016 11:47:02 +0000
Subject: [PATCH] Add frustum culling

---
 Cargo.lock        | 10 ++++++++++
 Cargo.toml        |  1 +
 src/main.rs       |  1 +
 src/render/mod.rs | 13 ++++++++++---
 4 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 805ed3b..9d0ebf3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,6 +4,7 @@ version = "0.0.1"
 dependencies = [
  "byteorder 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cgmath 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "collision 0.5.1 (git+https://github.com/csherratt/collision-rs?rev=f80825e)",
  "flate2 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "glutin 0.4.9 (git+https://github.com/Thinkofname/glutin?branch=hide-cursor-state-x11)",
  "hyper 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -94,6 +95,15 @@ dependencies = [
  "objc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "collision"
+version = "0.5.1"
+source = "git+https://github.com/csherratt/collision-rs?rev=f80825e#f80825eca687ff1053ff492e54fa782944c9cf6b"
+dependencies = [
+ "cgmath 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num 0.1.31 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "color_quant"
 version = "1.0.0"
diff --git a/Cargo.toml b/Cargo.toml
index 1758af1..1a6c350 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ rustc-serialize = "0.3.18"
 log = "0.3.5"
 cgmath = "0.7.0"
 lazy_static = "0.1.15"
+collision = {git = "https://github.com/csherratt/collision-rs", rev = "f80825e"}
 
 [dependencies.steven_gl]
 path = "./gl"
diff --git a/src/main.rs b/src/main.rs
index 516c579..65fc4aa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,6 +31,7 @@ extern crate cgmath;
 extern crate log;
 #[macro_use]
 extern crate lazy_static;
+extern crate collision;
 
 #[macro_use]
 pub mod macros;
diff --git a/src/render/mod.rs b/src/render/mod.rs
index 1d472b3..0301f0c 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -29,6 +29,7 @@ use byteorder::{WriteBytesExt, NativeEndian};
 use serde_json;
 use cgmath::{self, Vector, Point};
 use world;
+use collision;
 
 const ATLAS_SIZE: usize = 1024;
 
@@ -287,11 +288,17 @@ impl Renderer {
         self.chunk_shader.light_level.set_float(LIGHT_LEVEL);
         self.chunk_shader.sky_offset.set_float(SKY_OFFSET);
 
+        let frustum = collision::Frustum::from_matrix4(self.perspective_matrix * camera_matrix).unwrap();
+
         for (pos, info) in &self.chunks {
             if let Some(solid) = info.solid.as_ref() {
-                self.chunk_shader.offset.set_int3(pos.0, pos.1 * 4096, pos.2);
-                solid.array.bind();
-                gl::draw_elements(gl::TRIANGLES, solid.count, self.element_buffer_type, 0);
+                let min = cgmath::Point3::new(pos.0 as f32 * 16.0, -pos.1 as f32 * 16.0, pos.2 as f32 * 16.0);
+                let bounds = collision::Aabb3::new(min, min + cgmath::Vector3::new(16.0, -16.0, 16.0));
+                if frustum.contains(bounds) != collision::Relation::Out {
+                    self.chunk_shader.offset.set_int3(pos.0, pos.1 * 4096, pos.2);
+                    solid.array.bind();
+                    gl::draw_elements(gl::TRIANGLES, solid.count, self.element_buffer_type, 0);
+                }
             }
         }