Fix GC shutdown crash due to canvas objects not getting GC'ed at the end

Fix typo in Draw2D and add support for specifying the viewport size directly

src/common/2d/v_draw.h

@@ -328,3 +328,4 @@ public:
 };
 
 void Draw2D(F2DDrawer* drawer, FRenderState& state);
+void Draw2D(F2DDrawer* drawer, FRenderState& state, int x, int y, int width, int height);

src/common/rendering/hwrenderer/hw_draw2d.cpp

@@ -51,13 +51,18 @@
 
 CVAR(Bool, gl_aalines, false, CVAR_ARCHIVE) 
 
-void Draw2D(F2DDrawer *drawer, FRenderState &state)
+void Draw2D(F2DDrawer* drawer, FRenderState& state)
+{
+	const auto& mScreenViewport = screen->mScreenViewport;
+	Draw2D(drawer, state, mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
+}
+
+void Draw2D(F2DDrawer* drawer, FRenderState& state, int x, int y, int width, int height)
 {
 	twoD.Clock();
 
-	const auto &mScreenViewport = screen->mScreenViewport;
+	state.SetViewport(x, y, width, height);
-	state.SetViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
+	screen->mViewpoints->Set2D(state, drawer->GetWidth(), drawer->GetHeight());
-	screen->mViewpoints->Set2D(state, twod->GetWidth(), twod->GetHeight());
 
 	state.EnableStencil(false);
 	state.SetStencil(0, SOP_Keep, SF_AllOn);

src/common/textures/textures.h

@@ -304,6 +304,7 @@ public:
 };
 
 class FCanvas;
+extern TArray<FCanvas*> AllCanvases;
 
 // A texture that can be drawn to.
 
@@ -319,6 +320,15 @@ public:
 		aspectRatio = (float)width / height;
 	}
 
+	~FCanvasTexture()
+	{
+		if (Canvas)
+		{
+			AllCanvases.Delete(AllCanvases.Find(Canvas));
+			Canvas = nullptr;
+		}
+	}
+
 	void NeedUpdate() { bNeedsUpdate = true; }
 	void SetUpdated(bool rendertype) { bNeedsUpdate = false; bFirstUpdate = false; bLastUpdateType = rendertype; }
 	bool CheckNeedsUpdate() const { return bNeedsUpdate; }

src/rendering/hwrenderer/hw_entrypoint.cpp

@@ -359,7 +359,7 @@ sector_t* RenderView(player_t* player)
 			{
 				screen->RenderTextureView(canvas->Tex, [=](IntRect& bounds)
 					{
-						Draw2D(&canvas->Drawer, *screen->RenderState());
+						Draw2D(&canvas->Drawer, *screen->RenderState(), 0, 0, canvas->Tex->GetWidth(), canvas->Tex->GetHeight());
 						canvas->Drawer.Clear();
 					});
 				canvas->Tex->SetUpdated(true);