From 3712cb761b937e6d3df8c1dbc10e1fde6e08e29d Mon Sep 17 00:00:00 2001
From: "V. Shirokii" <vs.shirokii@gmail.com>
Date: Sat, 20 Jul 2024 13:54:16 +0100
Subject: [PATCH] Export skyvis polygons Fix sky not being rendered when
 skyportals are not visible

---
 src/common/rendering/rt/rt_main.cpp          |  1 +
 src/rendering/hwrenderer/scene/hw_portal.cpp | 21 ++++++++++++++++++++
 src/rendering/hwrenderer/scene/hw_sky.cpp    |  7 +++++++
 3 files changed, 29 insertions(+)

diff --git a/src/common/rendering/rt/rt_main.cpp b/src/common/rendering/rt/rt_main.cpp
index d4c5341ac..d3bf55a41 100644
--- a/src/common/rendering/rt/rt_main.cpp
+++ b/src/common/rendering/rt/rt_main.cpp
@@ -153,6 +153,7 @@ namespace cvar
     RT_CVAR( rt_sky,                    100.f,  "sky intensity")
     RT_CVAR( rt_sky_saturation,         1.f,    "sky saturation")
     RT_CVAR( rt_sky_stretch,            1.2f,   "how much to stretch the sky sphere along the vertical axis")
+    RT_CVAR( rt_sky_always,             true,   "always submit sky geometry (even if it's not visible in primary view)")
 
     // RT_CVAR( rt_sun,                 7000.f, "sun intensity")
     // RT_CVAR( rt_sun_diameter,        0.5f,   "sun angular diameter in degrees")
diff --git a/src/rendering/hwrenderer/scene/hw_portal.cpp b/src/rendering/hwrenderer/scene/hw_portal.cpp
index 9b4f65aa1..b55eef062 100644
--- a/src/rendering/hwrenderer/scene/hw_portal.cpp
+++ b/src/rendering/hwrenderer/scene/hw_portal.cpp
@@ -44,6 +44,10 @@
 
 EXTERN_CVAR(Int, r_mirror_recursions)
 EXTERN_CVAR(Bool, gl_portals)
+namespace cvar
+{
+EXTERN_CVAR( Bool, rt_sky_always )
+}
 
 void SetPlaneTextureRotation(FRenderState& state, HWSectorPlane* plane, FGameTexture* texture);
 
@@ -95,6 +99,20 @@ void FPortalSceneState::EndFrame(HWDrawInfo *di, FRenderState &state)
 		indent += "  ";
 	}
 
+#if HAVE_RT
+	// no sky walls/floor/ceiling visible... emulate it :(
+	if( di->Portals.size() == 0 )
+	{
+		if( cvar::rt_sky_always )
+		{
+			HWSkyInfo skyinfo{};
+			skyinfo.init( di, nullptr, sector_t::ceiling, 0, 0 );
+			auto emulated_skyportal = HWSkyPortal{ screen->mSkyData, &portalState, &skyinfo };
+			RenderPortal( &emulated_skyportal, state, true, di );
+		}
+	}
+	else
+#endif
 	while (di->Portals.Pop(p) && p)
 	{
 		if (gl_portalinfo) 
@@ -227,6 +245,9 @@ void HWPortal::DrawPortalStencil(FRenderState &state, int pass)
 	
 	for (unsigned int i = 0; i < mPrimIndices.Size(); i += 2)
 	{
+		auto rtexp = rtstate.push_type(
+		    RT_IsWallExportable( lines[ i / 2 ].seg ) ? RtPrim::ExportMap : RtPrim::Identity );
+
 		state.Draw(DT_TriangleFan, mPrimIndices[i], mPrimIndices[i + 1], i == 0);
 	}
 	if (NeedCap() && lines.Size() > 1)
diff --git a/src/rendering/hwrenderer/scene/hw_sky.cpp b/src/rendering/hwrenderer/scene/hw_sky.cpp
index dfa954530..498ca3f36 100644
--- a/src/rendering/hwrenderer/scene/hw_sky.cpp
+++ b/src/rendering/hwrenderer/scene/hw_sky.cpp
@@ -45,6 +45,13 @@ CVAR(Bool,gl_noskyboxes, false, 0)
 
 FTextureID GetSkyTexture(sector_t* sec, int plane, int second)
 {
+#if HAVE_RT
+	if( !sec )
+	{
+		return second ? level.skytexture2 : level.skytexture1;
+	}
+#endif
+
 	auto tex = sec->planes[plane].skytexture[second];
 	if (tex.isValid()) return tex;
 	return second ? sec->Level->skytexture2 : sec->Level->skytexture1;