From b3c8c8eb56227128dce4c905048c17bfa3bf91ec Mon Sep 17 00:00:00 2001
From: Petr Mikheev <ptmikheev@gmail.com>
Date: Sat, 9 Jul 2022 22:21:48 +0200
Subject: [PATCH] Support sky blending in multiview mode

---
 files/shaders/fog.glsl                       |  8 ++++----
 files/shaders/openmw_fragment.glsl           |  9 +++++++++
 files/shaders/openmw_fragment.h.glsl         | 11 ++++++++++-
 files/shaders/openmw_fragment_multiview.glsl | 11 ++++++++++-
 4 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/files/shaders/fog.glsl b/files/shaders/fog.glsl
index 9bf93079f3..d9d0548aa9 100644
--- a/files/shaders/fog.glsl
+++ b/files/shaders/fog.glsl
@@ -1,7 +1,8 @@
 uniform float far;
 
 #if @skyBlending
-uniform sampler2D sky;
+#include "openmw_fragment.h.glsl"
+
 uniform float skyBlendingStart;
 #endif
 
@@ -23,14 +24,13 @@ vec4 applyFogAtDist(vec4 color, float euclideanDist, float linearDist)
     color.xyz = mix(color.xyz, gl_Fog.color.xyz, fogValue);
 #endif
 
-#if @skyBlending && !@useOVR_multiview
+#if @skyBlending
     float fadeValue = clamp((far - dist) / (far - skyBlendingStart), 0.0, 1.0);
     fadeValue *= fadeValue;
 #ifdef ADDITIVE_BLENDING
     color.xyz *= fadeValue;
 #else
-    vec3 skyColor = texture2D(sky, gl_FragCoord.xy / screenRes).xyz;
-    color.xyz = mix(skyColor, color.xyz, fadeValue);
+    color.xyz = mix(mw_sampleSkyColor(gl_FragCoord.xy / screenRes), color.xyz, fadeValue);
 #endif
 #endif
 
diff --git a/files/shaders/openmw_fragment.glsl b/files/shaders/openmw_fragment.glsl
index 151f8fdb13..8c8302f3ae 100644
--- a/files/shaders/openmw_fragment.glsl
+++ b/files/shaders/openmw_fragment.glsl
@@ -31,3 +31,12 @@ vec4 mw_samplerLastShader(vec2 uv)
 {
     return texture2D(omw_SamplerLastShader, uv);
 }
+
+#if @skyBlending
+uniform sampler2D sky;
+
+vec3 mw_sampleSkyColor(vec2 uv)
+{
+    return texture2D(sky, uv).xyz;
+}
+#endif
diff --git a/files/shaders/openmw_fragment.h.glsl b/files/shaders/openmw_fragment.h.glsl
index c96912ead6..f7c1e2f21e 100644
--- a/files/shaders/openmw_fragment.h.glsl
+++ b/files/shaders/openmw_fragment.h.glsl
@@ -1,3 +1,6 @@
+#ifndef OPENMW_FRAGMENT_H_GLSL
+#define OPENMW_FRAGMENT_H_GLSL
+
 @link "openmw_fragment.glsl" if !@useOVR_multiview
 @link "openmw_fragment_multiview.glsl" if @useOVR_multiview
 
@@ -8,4 +11,10 @@ vec4 mw_sampleRefractionMap(vec2 uv);
 float mw_sampleRefractionDepthMap(vec2 uv);
 #endif
 
-vec4 mw_samplerLastShader(vec2 uv);
\ No newline at end of file
+vec4 mw_samplerLastShader(vec2 uv);
+
+#if @skyBlending
+vec3 mw_sampleSkyColor(vec2 uv);
+#endif
+
+#endif  // OPENMW_FRAGMENT_H_GLSL
diff --git a/files/shaders/openmw_fragment_multiview.glsl b/files/shaders/openmw_fragment_multiview.glsl
index 0ec9a3e12b..61f69cc2d9 100644
--- a/files/shaders/openmw_fragment_multiview.glsl
+++ b/files/shaders/openmw_fragment_multiview.glsl
@@ -35,4 +35,13 @@ uniform sampler2DArray omw_SamplerLastShader;
 vec4 mw_samplerLastShader(vec2 uv)
 {
     return texture2DArray(omw_SamplerLastShader, vec3((uv), gl_ViewID_OVR));
-}
\ No newline at end of file
+}
+
+#if @skyBlending
+uniform sampler2DArray sky;
+
+vec3 mw_sampleSkyColor(vec2 uv)
+{
+    return texture2DArray(sky, vec3((uv), gl_ViewID_OVR)).xyz;
+}
+#endif