- added some helper code mainly designed to help GZDoom maintain the vertex buffer for the textured automap.

src/am_map.cpp

@@ -1897,6 +1897,7 @@ void AM_drawSubsectors()
 	FDynamicColormap *colormap;
 	mpoint_t originpt;
 
+	screen->StartSimplePolys();
 	for (int i = 0; i < numsubsectors; ++i)
 	{
 		if (subsectors[i].flags & SSECF_POLYORG)
@@ -2049,6 +2050,7 @@ void AM_drawSubsectors()
 				);
 		}
 	}
+	screen->FinishSimplePolys();
 }
 
 //=============================================================================

src/v_draw.cpp

@@ -1244,6 +1244,19 @@ void DCanvas::Clear (int left, int top, int right, int bottom, int palcolor, uin
 	}
 }
 
+//==========================================================================
+//
+// no-ops. This is so that renderer backends can better manage the
+// processing of the subsector drawing in the automap
+//
+//==========================================================================
+
+void DCanvas::StartSimplePolys()
+{}
+
+void DCanvas::FinishSimplePolys()
+{}
+
 //==========================================================================
 //
 // DCanvas :: FillSimplePoly

src/v_video.h

@@ -216,6 +216,9 @@ public:
 	// Fill an area with a texture
 	virtual void FlatFill (int left, int top, int right, int bottom, FTexture *src, bool local_origin=false);
 
+	virtual void StartSimplePolys();
+	virtual void FinishSimplePolys();
+
 	// Fill a simple polygon with a texture
 	virtual void FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 		double originx, double originy, double scalex, double scaley, DAngle rotation,