From dacc9d03a70b5b3519923519ccb63dae7195163e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mariusz=20Kry=C5=84ski?= <mrk@sed.pl>
Date: Thu, 28 Oct 2021 22:53:22 +0000
Subject: [PATCH] Add support for IndexFormat::Uint16 (#2990)

# Objective

while testing wgpu/WebGL on mobile GPU I've noticed bevy always forces vertex index format to 32bit (and ignores mesh settings).

## Solution

the solution is to pass proper vertex index format in GpuIndexInfo to render_pass
---
 pipelined/bevy_pbr2/src/render/light.rs     | 2 +-
 pipelined/bevy_pbr2/src/render/mod.rs       | 2 +-
 pipelined/bevy_render2/src/mesh/mesh/mod.rs | 2 ++
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/pipelined/bevy_pbr2/src/render/light.rs b/pipelined/bevy_pbr2/src/render/light.rs
index 98b714ff58060..bd1a91c453bde 100644
--- a/pipelined/bevy_pbr2/src/render/light.rs
+++ b/pipelined/bevy_pbr2/src/render/light.rs
@@ -797,7 +797,7 @@ impl Draw<Shadow> for DrawShadowMesh {
             let gpu_mesh = meshes.into_inner().get(mesh_handle).unwrap();
             pass.set_vertex_buffer(0, gpu_mesh.vertex_buffer.slice(..));
             if let Some(index_info) = &gpu_mesh.index_info {
-                pass.set_index_buffer(index_info.buffer.slice(..), 0, IndexFormat::Uint32);
+                pass.set_index_buffer(index_info.buffer.slice(..), 0, index_info.index_format);
                 pass.draw_indexed(0..index_info.count, 0, 0..1);
             } else {
                 panic!("non-indexed drawing not supported yet")
diff --git a/pipelined/bevy_pbr2/src/render/mod.rs b/pipelined/bevy_pbr2/src/render/mod.rs
index 3125ca2a28fb8..183351cb970f9 100644
--- a/pipelined/bevy_pbr2/src/render/mod.rs
+++ b/pipelined/bevy_pbr2/src/render/mod.rs
@@ -685,7 +685,7 @@ impl RenderCommand<Transparent3d> for DrawMesh {
         let gpu_mesh = meshes.into_inner().get(mesh_handle).unwrap();
         pass.set_vertex_buffer(0, gpu_mesh.vertex_buffer.slice(..));
         if let Some(index_info) = &gpu_mesh.index_info {
-            pass.set_index_buffer(index_info.buffer.slice(..), 0, IndexFormat::Uint32);
+            pass.set_index_buffer(index_info.buffer.slice(..), 0, index_info.index_format);
             pass.draw_indexed(0..index_info.count, 0, 0..1);
         } else {
             panic!("non-indexed drawing not supported yet")
diff --git a/pipelined/bevy_render2/src/mesh/mesh/mod.rs b/pipelined/bevy_render2/src/mesh/mesh/mod.rs
index ae2da3f66c3b7..72f1e29a92c17 100644
--- a/pipelined/bevy_render2/src/mesh/mesh/mod.rs
+++ b/pipelined/bevy_render2/src/mesh/mesh/mod.rs
@@ -538,6 +538,7 @@ pub struct GpuMesh {
 pub struct GpuIndexInfo {
     pub buffer: Buffer,
     pub count: u32,
+    pub index_format: IndexFormat,
 }
 
 impl RenderAsset for Mesh {
@@ -567,6 +568,7 @@ impl RenderAsset for Mesh {
                 label: None,
             }),
             count: mesh.indices().unwrap().len() as u32,
+            index_format: mesh.indices().unwrap().into(),
         });
 
         Ok(GpuMesh {