Add bottomclip parameter to FillSimplePoly() for the software implementation

- Polygons will be clipped to bottomclip. If this is zero or below, they
  will be clipped to the bottom of the screen instead. This keeps the
  polygons from overwriting the status bar border for sofware 2D. The
  hardware version ignores it, since it always draws the status bar border
  every frame.

src/am_map.cpp

@@ -2046,7 +2046,8 @@ void AM_drawSubsectors()
 				scale / scaley,
 				rotation,
 				colormap,
-				floorlight
+				floorlight,
+				f_y + f_h
 				);
 		}
 	}

src/v_draw.cpp

@@ -1282,7 +1282,7 @@ void DCanvas::FinishSimplePolys()
 
 void DCanvas::FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 	double originx, double originy, double scalex, double scaley, DAngle rotation,
-	FDynamicColormap *colormap, int lightlevel)
+	FDynamicColormap *colormap, int lightlevel, int bottomclip)
 {
 #ifndef NO_SWRENDER
 	// Use an equation similar to player sprites to determine shade
@@ -1300,6 +1300,11 @@ void DCanvas::FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 		return;
 	}
 
+	if (bottomclip <= 0)
+	{
+		bottomclip = Height;
+	}
+
 	// Find the extents of the polygon, in particular the highest and lowest points.
 	for (botpt = toppt = 0, boty = topy = points[0].Y, leftx = rightx = points[0].X, i = 1; i <= npoints; ++i)
 	{
@@ -1322,7 +1327,7 @@ void DCanvas::FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 			rightx = points[i].X;
 		}
 	}
-	if (topy >= Height ||		// off the bottom of the screen
+	if (topy >= bottomclip ||	// off the bottom of the screen
 		boty <= 0 ||			// off the top of the screen
 		leftx >= Width ||		// off the right of the screen
 		rightx <= 0)			// off the left of the screen
@@ -1377,13 +1382,13 @@ void DCanvas::FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 	{
 		x = FLOAT2FIXED(points[pt1].X + 0.5f);
 		y2 = xs_RoundToInt(points[pt2].Y + 0.5f);
-		if (y1 >= y2 || (y1 < 0 && y2 < 0) || (y1 >= Height && y2 >= Height))
+		if (y1 >= y2 || (y1 < 0 && y2 < 0) || (y1 >= bottomclip && y2 >= bottomclip))
 		{
 		}
 		else
 		{
 			fixed_t xinc = FLOAT2FIXED((points[pt2].X - points[pt1].X) / (points[pt2].Y - points[pt1].Y));
-			int y3 = MIN(y2, Height);
+			int y3 = MIN(y2, bottomclip);
 			if (y1 < 0)
 			{
 				x += xinc * -y1;
@@ -1408,13 +1413,13 @@ void DCanvas::FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 	{
 		x = FLOAT2FIXED(points[pt1].X + 0.5f);
 		y2 = xs_RoundToInt(points[pt2].Y + 0.5f);
-		if (y1 >= y2 || (y1 < 0 && y2 < 0) || (y1 >= Height && y2 >= Height))
+		if (y1 >= y2 || (y1 < 0 && y2 < 0) || (y1 >= bottomclip && y2 >= bottomclip))
 		{
 		}
 		else
 		{
 			fixed_t xinc = FLOAT2FIXED((points[pt2].X - points[pt1].X) / (points[pt2].Y - points[pt1].Y));
-			int y3 = MIN(y2, Height);
+			int y3 = MIN(y2, bottomclip);
 			if (y1 < 0)
 			{
 				x += xinc * -y1;

src/v_video.h

@@ -224,7 +224,7 @@ public:
 	// 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,
-		struct FDynamicColormap *colormap, int lightlevel);
+		struct FDynamicColormap *colormap, int lightlevel, int bottomclip);
 
 	// Set an area to a specified color
 	virtual void Clear (int left, int top, int right, int bottom, int palcolor, uint32 color);

src/win32/fb_d3d9.cpp

@@ -3084,11 +3084,16 @@ void D3DFB::FlatFill(int left, int top, int right, int bottom, FTexture *src, bo
 //
 // Here, "simple" means that a simple triangle fan can draw it.
 //
+// Bottomclip is ignored by this implementation, since the hardware renderer
+// will unconditionally draw the status bar border every frame on top of the
+// polygons, so there's no need to waste time setting up a special scissor
+// rectangle here and needlessly forcing separate batches.
+//
 //==========================================================================
 
 void D3DFB::FillSimplePoly(FTexture *texture, FVector2 *points, int npoints,
 	double originx, double originy, double scalex, double scaley,
-	DAngle rotation, FDynamicColormap *colormap, int lightlevel)
+	DAngle rotation, FDynamicColormap *colormap, int lightlevel, int bottomclip)
 {
 	// Use an equation similar to player sprites to determine shade
 	double fadelevel = clamp((LIGHT2SHADE(lightlevel)/65536. - 12) / NUMCOLORMAPS, 0.0, 1.0);
@@ -3109,7 +3114,7 @@ void D3DFB::FillSimplePoly(FTexture *texture, FVector2 *points, int npoints,
 	}
 	if (In2D < 2)
 	{
-		Super::FillSimplePoly(texture, points, npoints, originx, originy, scalex, scaley, rotation, colormap, lightlevel);
+		Super::FillSimplePoly(texture, points, npoints, originx, originy, scalex, scaley, rotation, colormap, lightlevel, bottomclip);
 		return;
 	}
 	if (!InScene)

src/win32/win32iface.h

@@ -265,7 +265,7 @@ public:
 	void DrawPixel(int x, int y, int palcolor, uint32 rgbcolor);
 	void FillSimplePoly(FTexture *tex, FVector2 *points, int npoints,
 		double originx, double originy, double scalex, double scaley,
-		DAngle rotation, FDynamicColormap *colormap, int lightlevel);
+		DAngle rotation, FDynamicColormap *colormap, int lightlevel, int bottomclip) override;
 	bool WipeStartScreen(int type);
 	void WipeEndScreen();
 	bool WipeDo(int ticks);