- add two-sided culling support in software and poly

src/polyrenderer/drawers/poly_triangle.cpp

@@ -79,6 +79,11 @@ void PolyTriangleDrawer::SetCullCCW(const DrawerCommandQueuePtr &queue, bool ccw
 	queue->Push<PolySetCullCCWCommand>(ccw);
 }
 
+void PolyTriangleDrawer::SetTwoSided(const DrawerCommandQueuePtr &queue, bool twosided)
+{
+	queue->Push<PolySetTwoSidedCommand>(twosided);
+}
+
 void PolyTriangleDrawer::SetWeaponScene(const DrawerCommandQueuePtr &queue, bool enable)
 {
 	queue->Push<PolySetWeaponSceneCommand>(enable);
@@ -348,6 +353,14 @@ void PolyTriangleThreadData::DrawShadedTriangle(const ShadedTriVertex *vert, boo
 		}
 	}
 
+	if (twosided && numclipvert > 2)
+	{
+		args->v1 = &clippedvert[0];
+		args->v2 = &clippedvert[1];
+		args->v3 = &clippedvert[2];
+		ccw = !IsFrontfacing(args);
+	}
+
 	// Draw screen triangles
 	if (ccw)
 	{
@@ -588,6 +601,17 @@ void PolySetCullCCWCommand::Execute(DrawerThread *thread)
 
 /////////////////////////////////////////////////////////////////////////////
 
+PolySetTwoSidedCommand::PolySetTwoSidedCommand(bool twosided) : twosided(twosided)
+{
+}
+
+void PolySetTwoSidedCommand::Execute(DrawerThread *thread)
+{
+	PolyTriangleThreadData::Get(thread)->SetTwoSided(twosided);
+}
+
+/////////////////////////////////////////////////////////////////////////////
+
 PolySetWeaponSceneCommand::PolySetWeaponSceneCommand(bool value) : value(value)
 {
 }

src/polyrenderer/drawers/poly_triangle.h

@@ -35,6 +35,7 @@ public:
 	static void ClearBuffers(DCanvas *canvas);
 	static void SetViewport(const DrawerCommandQueuePtr &queue, int x, int y, int width, int height, DCanvas *canvas, bool span_drawers);
 	static void SetCullCCW(const DrawerCommandQueuePtr &queue, bool ccw);
+	static void SetTwoSided(const DrawerCommandQueuePtr &queue, bool twosided);
 	static void SetWeaponScene(const DrawerCommandQueuePtr &queue, bool enable);
 	static void SetTransform(const DrawerCommandQueuePtr &queue, const Mat4f *objectToClip);
 };
@@ -47,6 +48,7 @@ public:
 	void SetViewport(int x, int y, int width, int height, uint8_t *dest, int dest_width, int dest_height, int dest_pitch, bool dest_bgra, bool span_drawers);
 	void SetTransform(const Mat4f *objectToClip);
 	void SetCullCCW(bool value) { ccw = value; }
+	void SetTwoSided(bool value) { twosided = value; }
 	void SetWeaponScene(bool value) { weaponScene = value; }
 
 	void DrawElements(const PolyDrawArgs &args);
@@ -81,6 +83,7 @@ private:
 	bool dest_bgra = false;
 	uint8_t *dest = nullptr;
 	bool ccw = true;
+	bool twosided = false;
 	bool weaponScene = false;
 	const Mat4f *objectToClip = nullptr;
 	bool span_drawers = false;
@@ -112,6 +115,18 @@ private:
 	bool ccw;
 };
 
+class PolySetTwoSidedCommand : public DrawerCommand
+{
+public:
+	PolySetTwoSidedCommand(bool twosided);
+
+	void Execute(DrawerThread *thread) override;
+	FString DebugInfo() override { return "PolySetCullCCWCommand"; }
+
+private:
+	bool twosided;
+};
+
 class PolySetWeaponSceneCommand : public DrawerCommand
 {
 public:

src/polyrenderer/scene/poly_model.cpp

@@ -56,10 +56,12 @@ void PolyModelRenderer::BeginDrawModel(AActor *actor, FSpriteModelFrame *smf, co
 	ModelActor = actor;
 	const_cast<VSMatrix &>(objectToWorldMatrix).copy(ObjectToWorld.Matrix);
 	SetTransform();
+	PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, true);
 }
 
 void PolyModelRenderer::EndDrawModel(AActor *actor, FSpriteModelFrame *smf)
 {
+	PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, false);
 	ModelActor = nullptr;
 }
 
@@ -98,12 +100,14 @@ void PolyModelRenderer::BeginDrawHUDModel(AActor *actor, const VSMatrix &objectT
 	const_cast<VSMatrix &>(objectToWorldMatrix).copy(ObjectToWorld.Matrix);
 	SetTransform();
 	PolyTriangleDrawer::SetWeaponScene(Thread->DrawQueue, true);
+	PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, true);
 }
 
 void PolyModelRenderer::EndDrawHUDModel(AActor *actor)
 {
 	ModelActor = nullptr;
 	PolyTriangleDrawer::SetWeaponScene(Thread->DrawQueue, false);
+	PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, false);
 }
 
 void PolyModelRenderer::SetInterpolation(double interpolation)

src/swrenderer/things/r_model.cpp

@@ -120,11 +120,13 @@ namespace swrenderer
 		}
 
 		SetTransform();
+		PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, true);
 	}
 
 	void SWModelRenderer::EndDrawModel(AActor *actor, FSpriteModelFrame *smf)
 	{
 		ModelActor = nullptr;
+		PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, false);
 	}
 
 	IModelVertexBuffer *SWModelRenderer::CreateVertexBuffer(bool needindex, bool singleframe)
@@ -183,12 +185,14 @@ namespace swrenderer
 		ClipBottom = {};
 		SetTransform();
 		PolyTriangleDrawer::SetWeaponScene(Thread->DrawQueue, true);
+		PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, true);
 	}
 
 	void SWModelRenderer::EndDrawHUDModel(AActor *actor)
 	{
 		ModelActor = nullptr;
 		PolyTriangleDrawer::SetWeaponScene(Thread->DrawQueue, false);
+		PolyTriangleDrawer::SetTwoSided(Thread->DrawQueue, false);
 	}
 
 	void SWModelRenderer::SetInterpolation(double interpolation)