From 1b80f05e8212965c3f2835443aa3b6200ca943d5 Mon Sep 17 00:00:00 2001
From: Joshua Barretto <joshua.s.barretto@gmail.com>
Date: Thu, 20 Aug 2020 22:34:58 +0100
Subject: [PATCH] Centred particle meshes correctly

---
 assets/voxygen/shaders/particle-vert.glsl |  2 +-
 voxygen/src/render/mesh.rs                |  3 +++
 voxygen/src/scene/particle.rs             | 17 +++++++++++------
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/assets/voxygen/shaders/particle-vert.glsl b/assets/voxygen/shaders/particle-vert.glsl
index 269a3e8e41..a78551a935 100644
--- a/assets/voxygen/shaders/particle-vert.glsl
+++ b/assets/voxygen/shaders/particle-vert.glsl
@@ -217,7 +217,7 @@ void main() {
 		);
 	}
 
-	f_pos = (inst_pos - focus_off.xyz) + ((v_pos - 0.5) * attr.scale * SCALE * mat3(attr.rot) + attr.offs);
+	f_pos = (inst_pos - focus_off.xyz) + (v_pos * attr.scale * SCALE * mat3(attr.rot) + attr.offs);
 
 	// First 3 normals are negative, next 3 are positive
 	// TODO: Make particle normals match orientation
diff --git a/voxygen/src/render/mesh.rs b/voxygen/src/render/mesh.rs
index 4ddbe65843..cd38e88ae4 100644
--- a/voxygen/src/render/mesh.rs
+++ b/voxygen/src/render/mesh.rs
@@ -28,6 +28,9 @@ impl<P: Pipeline> Mesh<P> {
     /// Get a slice referencing the vertices of this mesh.
     pub fn vertices(&self) -> &[P::Vertex] { &self.verts }
 
+    /// Get a mutable slice referencing the vertices of this mesh.
+    pub fn vertices_mut(&mut self) -> &mut [P::Vertex] { &mut self.verts }
+
     /// Push a new vertex onto the end of this mesh.
     pub fn push(&mut self, vert: P::Vertex) { self.verts.push(vert); }
 
diff --git a/voxygen/src/scene/particle.rs b/voxygen/src/scene/particle.rs
index 536c2fa9f1..2586d335a7 100644
--- a/voxygen/src/scene/particle.rs
+++ b/voxygen/src/scene/particle.rs
@@ -14,7 +14,7 @@ use common::{
     spiral::Spiral2d,
     state::DeltaTime,
     terrain::TerrainChunk,
-    vol::RectRasterableVol,
+    vol::{RectRasterableVol, SizedVol},
 };
 use dot_vox::DotVoxData;
 use hashbrown::HashMap;
@@ -367,11 +367,16 @@ fn default_cache(renderer: &mut Renderer) -> HashMap<&'static str, Model<Particl
             guillotiere::Size::new(i32::from(max_texture_size), i32::from(max_texture_size));
         let mut greedy = GreedyMesh::new(max_size);
 
-        let mesh = Meshable::<ParticlePipeline, &mut GreedyMesh>::generate_mesh(
-            Segment::from(vox.as_ref()),
-            &mut greedy,
-        )
-        .0;
+        let segment = Segment::from(vox.as_ref());
+        let segment_size = segment.size();
+        let mut mesh =
+            Meshable::<ParticlePipeline, &mut GreedyMesh>::generate_mesh(segment, &mut greedy).0;
+        // Center particle vertices around origin
+        for vert in mesh.vertices_mut() {
+            vert.pos[0] -= segment_size.x as f32 / 2.0;
+            vert.pos[1] -= segment_size.y as f32 / 2.0;
+            vert.pos[2] -= segment_size.z as f32 / 2.0;
+        }
 
         // NOTE: Ignoring coloring / lighting for now.
         drop(greedy);