From f312299e62d98799b2e2f2e51aebaa675660ef39 Mon Sep 17 00:00:00 2001
From: scott-c <xodster@gmail.com>
Date: Fri, 16 Aug 2019 21:45:10 +0800
Subject: [PATCH] Replace view distance culling with frustum culling

---
 voxygen/src/scene/camera.rs | 10 ++++++++++
 voxygen/src/scene/figure.rs | 18 +++---------------
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/voxygen/src/scene/camera.rs b/voxygen/src/scene/camera.rs
index 3021652bef..b5923b0129 100644
--- a/voxygen/src/scene/camera.rs
+++ b/voxygen/src/scene/camera.rs
@@ -2,6 +2,7 @@ use client::Client;
 use common::vol::{ReadVol, Vox};
 use std::f32::consts::PI;
 use vek::*;
+use frustum_query::frustum::Frustum;
 
 const NEAR_PLANE: f32 = 0.01;
 const FAR_PLANE: f32 = 10000.0;
@@ -92,6 +93,15 @@ impl Camera {
         (view_mat, proj_mat, cam_pos)
     }
 
+    pub fn frustum(&self, client: &Client) -> Frustum {
+        let (view_mat, proj_mat, _) = self.compute_dependents(client);
+
+        Frustum::from_modelview_and_projection(
+            &view_mat.into_col_array(),
+            &proj_mat.into_col_array(),
+        )
+    }
+
     /// Rotate the camera about its focus by the given delta, limiting the input accordingly.
     pub fn rotate_by(&mut self, delta: Vec3<f32>) {
         // Wrap camera yaw
diff --git a/voxygen/src/scene/figure.rs b/voxygen/src/scene/figure.rs
index 80bcdf5b09..ddbe94e902 100644
--- a/voxygen/src/scene/figure.rs
+++ b/voxygen/src/scene/figure.rs
@@ -851,14 +851,7 @@ impl FigureMgr {
         let tick = client.get_tick();
         let ecs = client.state().ecs();
 
-        let view_distance = client.view_distance().unwrap_or(1);
-        // Get player position.
-        let player_pos = client
-            .state()
-            .ecs()
-            .read_storage::<comp::Pos>()
-            .get(client.entity())
-            .map_or(Vec3::zero(), |pos| pos.0);
+        let frustum = camera.frustum(client);
 
         for (entity, _, _, _, body, _) in (
             &ecs.entities(),
@@ -869,13 +862,8 @@ impl FigureMgr {
             ecs.read_storage::<comp::Stats>().maybe(),
         )
             .join()
-            // Don't render figures outside the vd
-            .filter(|(_, pos, _, _, _, _)| {
-                (pos.0 - player_pos)
-                    .map2(TerrainChunkSize::SIZE, |d, sz| d.abs() as f32 / sz as f32)
-                    .magnitude()
-                    < view_distance as f32
-            })
+            // Don't render figures outside of frustum (camera viewport, max draw distance is farplane) 
+            .filter(|(_, pos, _, _, _, _)| frustum.sphere_intersecting(&pos.0.x, &pos.0.y, &pos.0.z, &0.0))
             // Don't render dead entities
             .filter(|(_, _, _, _, _, stats)| stats.map_or(true, |s| !s.is_dead))
         {