From 0ae93318e320a54fb094b4dd45f3586063ae65d9 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 28 Mar 2021 21:00:24 +0200
Subject: [PATCH] - flip camera textures to have the correct orientation.

---
 source/core/rendering/scene/hw_flats.cpp   |  6 ++++--
 source/core/rendering/scene/hw_sprites.cpp |  1 +
 source/core/rendering/scene/hw_walls.cpp   | 10 ++++++++++
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/source/core/rendering/scene/hw_flats.cpp b/source/core/rendering/scene/hw_flats.cpp
index e69a1a4e4..9ef8de751 100644
--- a/source/core/rendering/scene/hw_flats.cpp
+++ b/source/core/rendering/scene/hw_flats.cpp
@@ -98,6 +98,7 @@ void HWFlat::SetupLights(HWDrawInfo *di, FLightNode * node, FDynLightData &light
 void HWFlat::MakeVertices()
 {
 	if (vertcount > 0) return;
+	bool canvas = texture->isHardwareCanvas();
 	if (sprite == nullptr)
 	{
 		auto mesh = sectorGeometry.get(sec - sector, plane);
@@ -109,7 +110,7 @@ void HWFlat::MakeVertices()
 			auto& pt = mesh->vertices[i];
 			auto& uv = mesh->texcoords[i];
 			vp->SetVertex(pt.X, pt.Z, pt.Y);
-			vp->SetTexCoord(uv.X, uv.Y);
+			vp->SetTexCoord(uv.X, canvas? 1.f - uv.Y : uv.Y);
 			vp++;
 		}
 		vertindex = ret.second;
@@ -129,7 +130,8 @@ void HWFlat::MakeVertices()
 			const static unsigned indices[] = { 0, 1, 2, 0, 2, 3 };
 			int j = indices[i];
 			vp->SetVertex(pos[j].x * (1 / 16.f), z, pos[j].y * (1 / -16.f));
-			vp->SetTexCoord(j == 1 || j == 2 ? 1.f - x : x, j == 2 || j == 3 ? 1.f - x : x);
+			if (!canvas) vp->SetTexCoord(j == 1 || j == 2 ? 1.f - x : x, j == 2 || j == 3 ? 1.f - y : y);
+			else vp->SetTexCoord(j == 1 || j == 2 ? 1.f - x : x, j == 2 || j == 3 ? y : 1.f - y);
 			vp++;
 		}
 		vertindex = ret.second;
diff --git a/source/core/rendering/scene/hw_sprites.cpp b/source/core/rendering/scene/hw_sprites.cpp
index f3b95cfcd..ebe9202c9 100644
--- a/source/core/rendering/scene/hw_sprites.cpp
+++ b/source/core/rendering/scene/hw_sprites.cpp
@@ -391,6 +391,7 @@ void HWSprite::Process(HWDrawInfo* di, spritetype* spr, sectortype* sector, int
 		ur = (spr->cstat & CSTAT_SPRITE_XFLIP) ? 1.f : 0.f;
 		vt = (spr->cstat & CSTAT_SPRITE_YFLIP) ? 0.f : 1.f;
 		vb = (spr->cstat & CSTAT_SPRITE_YFLIP) ? 1.f : 0.f;
+		if (tex->isHardwareCanvas()) std::swap(vt, vb);
 
 		float viewvecX = vp.ViewVector.X;
 		float viewvecY = vp.ViewVector.Y;
diff --git a/source/core/rendering/scene/hw_walls.cpp b/source/core/rendering/scene/hw_walls.cpp
index c582fd6ff..ee87ead81 100644
--- a/source/core/rendering/scene/hw_walls.cpp
+++ b/source/core/rendering/scene/hw_walls.cpp
@@ -401,6 +401,15 @@ void HWWall::PutWall(HWDrawInfo *di, bool translucent)
 		flags |= HWF_TRANSLUCENT;
 		ViewDistance = (di->Viewpoint.Pos.XY() - DVector2((glseg.x1 + glseg.x2) * 0.5f, (glseg.y1 + glseg.y2) * 0.5f)).LengthSquared();
 	}
+
+	if (texture->isHardwareCanvas())
+	{
+		tcs[UPLFT].v = 1.f - tcs[UPLFT].v;
+		tcs[LOLFT].v = 1.f - tcs[LOLFT].v;
+		tcs[UPRGT].v = 1.f - tcs[UPRGT].v;
+		tcs[LORGT].v = 1.f - tcs[LORGT].v;
+	}
+
 	
 	if (!screen->BuffersArePersistent())
 	{
@@ -1127,6 +1136,7 @@ void HWWall::ProcessWallSprite(HWDrawInfo* di, spritetype* spr, sectortype* sect
 	tcs[LORGT].u = tcs[UPRGT].u = (spr->cstat & CSTAT_SPRITE_XFLIP) ? 0.f : 1.f;
 	tcs[UPLFT].v = tcs[UPRGT].v = (spr->cstat & CSTAT_SPRITE_YFLIP) ? 1.f : 0.f;
 	tcs[LOLFT].v = tcs[LORGT].v = (spr->cstat & CSTAT_SPRITE_YFLIP) ? 0.f : 1.f;
+
 	zbottom[0] = zbottom[1] = (sprz) * (1 / -256.);
 	ztop[0] = ztop[1] =  (sprz - ((height * spr->yrepeat) << 2)) * (1 / -256.);