From 37b3c96131ea81e52a4f2a8957e34afb43e9ba36 Mon Sep 17 00:00:00 2001
From: samcake <samuel.gateau@gmail.com>
Date: Mon, 31 Oct 2016 17:40:34 -0700
Subject: [PATCH] fixing the lighting problem in stereo

---
 libraries/gpu-gl/src/gpu/gl/GLBackend.h       |  3 ++-
 .../src/deferred_light_limited.slv            | 21 +++++++++++++++++++
 .../render-utils/src/deferred_light_spot.slv  | 19 +++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/libraries/gpu-gl/src/gpu/gl/GLBackend.h b/libraries/gpu-gl/src/gpu/gl/GLBackend.h
index 6fca8cc5a7..1011a7f5a2 100644
--- a/libraries/gpu-gl/src/gpu/gl/GLBackend.h
+++ b/libraries/gpu-gl/src/gpu/gl/GLBackend.h
@@ -30,7 +30,8 @@
 #include "GLShared.h"
 
 
-// Pick one from the 3: THis version is the most efficient as of now
+// Different versions for the stereo drawcall
+// Current preferred is  "instanced" which draw the shape twice but instanced and rely on clipping plane to draw left/right side only
 //#define GPU_STEREO_TECHNIQUE_DOUBLED_SIMPLE
 //#define GPU_STEREO_TECHNIQUE_DOUBLED_SMARTER
 #define GPU_STEREO_TECHNIQUE_INSTANCED
diff --git a/libraries/render-utils/src/deferred_light_limited.slv b/libraries/render-utils/src/deferred_light_limited.slv
index 42ac1d6dfb..36e281ab5b 100644
--- a/libraries/render-utils/src/deferred_light_limited.slv
+++ b/libraries/render-utils/src/deferred_light_limited.slv
@@ -33,9 +33,14 @@ void main(void) {
         vec4 projected = gl_Position / gl_Position.w;
         projected.xy = (projected.xy + 1.0) * 0.5;
 
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+#else
         if (cam_isStereo()) {
             projected.x = 0.5 * (projected.x + cam_getStereoSide());
         }
+#endif
+#endif
         _texCoord0 = vec4(projected.xy, 0.0, 1.0) * gl_Position.w;
     } else {
         const float depth = -1.0; //Draw at near plane
@@ -47,11 +52,27 @@ void main(void) {
         );
         vec4 pos = UNIT_QUAD[gl_VertexID];
 
+
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+        TransformCamera cam = getTransformCamera();
+        <$transformStereoClipsSpace(cam, pos)$>
+#endif
+#endif
+
         _texCoord0 = vec4((pos.xy + 1.0) * 0.5, 0.0, 1.0);
 
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+#else
         if (cam_isStereo()) {
             _texCoord0.x = 0.5 * (_texCoord0.x + cam_getStereoSide());
         }
+#endif
+#endif
+
         gl_Position = pos;
+
     }
+
 }
diff --git a/libraries/render-utils/src/deferred_light_spot.slv b/libraries/render-utils/src/deferred_light_spot.slv
index 4a1a0472aa..935d756b28 100755
--- a/libraries/render-utils/src/deferred_light_spot.slv
+++ b/libraries/render-utils/src/deferred_light_spot.slv
@@ -46,9 +46,14 @@ void main(void) {
             vec4 projected = gl_Position / gl_Position.w;
         projected.xy = (projected.xy + 1.0) * 0.5;
 
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+#else
         if (cam_isStereo()) {
             projected.x = 0.5 * (projected.x + cam_getStereoSide());
         }
+#endif
+#endif
         _texCoord0 = vec4(projected.xy, 0.0, 1.0) * gl_Position.w;
     } else {
         const float depth = -1.0; //Draw at near plane
@@ -60,10 +65,24 @@ void main(void) {
         );
         vec4 pos = UNIT_QUAD[gl_VertexID];
 
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+        TransformCamera cam = getTransformCamera();
+        <$transformStereoClipsSpace(cam, pos)$>
+#endif
+#endif
+
         _texCoord0 = vec4((pos.xy + 1.0) * 0.5, 0.0, 1.0);
+
+#ifdef GPU_TRANSFORM_IS_STEREO
+#ifdef GPU_TRANSFORM_STEREO_SPLIT_SCREEN
+#else
         if (cam_isStereo()) {
             _texCoord0.x = 0.5 * (_texCoord0.x + cam_getStereoSide());
         }
+#endif
+#endif
+
         gl_Position = pos;
     }
 }