From 68a2efd3c5db62c2c011ccbad84f58be5e539fe3 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvark@fastmail.com>
Date: Tue, 29 Jun 2021 02:18:56 -0400
Subject: [PATCH] glsl-out: make the cs adjustment to also flip Y

---
 src/back/glsl/mod.rs                      | 4 ++--
 tests/out/glsl/quad-vert.main.Vertex.glsl | 2 +-
 tests/out/glsl/quad.main.Vertex.glsl      | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/back/glsl/mod.rs b/src/back/glsl/mod.rs
index 9090aba396..ef1a71cbc0 100644
--- a/src/back/glsl/mod.rs
+++ b/src/back/glsl/mod.rs
@@ -130,7 +130,7 @@ bitflags::bitflags! {
     #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
     #[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
     pub struct WriterFlags: u32 {
-        /// Extend output Z from (0,1) to (-1,1).
+        /// Flip output Y and extend Z from (0,1) to (-1,1).
         const ADJUST_COORDINATE_SPACE = 0x1;
         /// Supports GL_EXT_texture_shadow_lod on the host, which provides
         /// additional functions on shadows and arrays of shadows.
@@ -1520,7 +1520,7 @@ impl<'a, W: Write> Writer<'a, W> {
                             {
                                 writeln!(
                                     self.out,
-                                    "gl_Position.z = gl_Position.z * 2.0 - gl_Position.w;",
+                                    "gl_Position.yz = vec2(-gl_Position.y, gl_Position.z * 2.0 - gl_Position.w);",
                                 )?;
                                 write!(self.out, "{}", INDENT.repeat(indent))?;
                             }
diff --git a/tests/out/glsl/quad-vert.main.Vertex.glsl b/tests/out/glsl/quad-vert.main.Vertex.glsl
index fb0a07283b..b60099c18e 100644
--- a/tests/out/glsl/quad-vert.main.Vertex.glsl
+++ b/tests/out/glsl/quad-vert.main.Vertex.glsl
@@ -49,7 +49,7 @@ void main() {
     type10 _tmp_return = type10(_expr10, _expr11, _expr12, _expr13, _expr14);
     _vs2fs_location0 = _tmp_return.member;
     gl_Position = _tmp_return.gen_gl_Position;
-    gl_Position.z = gl_Position.z * 2.0 - gl_Position.w;
+    gl_Position.yz = vec2(-gl_Position.y, gl_Position.z * 2.0 - gl_Position.w);
     return;
 }
 
diff --git a/tests/out/glsl/quad.main.Vertex.glsl b/tests/out/glsl/quad.main.Vertex.glsl
index e32509b959..cde8ac8d46 100644
--- a/tests/out/glsl/quad.main.Vertex.glsl
+++ b/tests/out/glsl/quad.main.Vertex.glsl
@@ -17,7 +17,7 @@ void main() {
     VertexOutput _tmp_return = VertexOutput(uv, vec4((1.2 * pos), 0.0, 1.0));
     _vs2fs_location0 = _tmp_return.uv;
     gl_Position = _tmp_return.position;
-    gl_Position.z = gl_Position.z * 2.0 - gl_Position.w;
+    gl_Position.yz = vec2(-gl_Position.y, gl_Position.z * 2.0 - gl_Position.w);
     return;
 }