From e7f93ab55aabf5040755b7626df97f1151f9dd29 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Wed, 24 Oct 2018 08:59:10 +0000
Subject: Tweaks to road demo.

---
 xd.c | 52 ++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 14 deletions(-)

diff --git a/xd.c b/xd.c
index 44a2ef0..703ca4f 100644
--- a/xd.c
+++ b/xd.c
@@ -281,7 +281,7 @@ static DemoInfo		demotbl[NO_DEMOS]=
 				UsesPixmap
 			    },
 			    {
-				"Road Demo",
+				"Road Demo (LMB toggle culling)",
 				RoadDemo,
 				UsesPixmap
 			    },
@@ -4332,6 +4332,7 @@ static void RoadDemo(void)
     static double dx, dy;
     static double dxi, dyi;
     static int dcount;
+    static int cull = TRUE;
 
     int f,r;
     double x, y, z;
@@ -4349,7 +4350,7 @@ static void RoadDemo(void)
 	{
 	    if (dcount == 0 && dx == 0 && dy == 0)
 	    {
-	    	dcount = RND2(20, 500);
+	    	dcount = RND2(200, 500);
 		dx = 0;
 		dy = 0;
 		dxi = RND(10) / 40.0 - 0.125;
@@ -4376,17 +4377,23 @@ static void RoadDemo(void)
 		    double sdx = SgnF(dx);
 		    double sdy = SgnF(dy);
 
-		    dx -= dxi;
-		    dy -= dyi;
+		    if (dx != 0.0)
+		    {
+			dx -= dxi;
+		    }
+
+		    if (dy != 0.0)
+		    {
+			dy -= dyi;
+		    }
 
 		    if (SgnF(dx) != sdx)
 		    {
 		    	dx = 0;
-			dy = 0;
 		    }
-		    else if (SgnF(dy) != sdy)
+
+		    if (SgnF(dy) != sdy)
 		    {
-		    	dx = 0;
 		    	dy = 0;
 		    }
 		}
@@ -4397,6 +4404,17 @@ static void RoadDemo(void)
 	}
     }
 
+    if (mouse_b&Button1Mask)
+    {
+	static time_t bounce=0;
+
+	if (bounce!=time(NULL))
+	{
+	    cull = !cull;
+	    bounce=time(NULL);
+	}
+    }
+
     Cls();
 
     x = -ROAD_WIDTH / 2;
@@ -4449,7 +4467,7 @@ static void RoadDemo(void)
 
 	if (Project(rx2, ry2, rz2, &xp))
 	{
-	    if (xp.y < max_y)
+	    if (!cull || xp.y < max_y)
 	    {
 		Plot(xp.x, xp.y, white);
 
@@ -4468,7 +4486,7 @@ static void RoadDemo(void)
 	{
 	    if (dcount == 0 && dx == 0 && dy == 0)
 	    {
-	    	dcount = RND2(20, 500);
+	    	dcount = RND2(200, 500);
 		dx = 0;
 		dy = 0;
 		dxi = RND(10) / 40.0 - 0.125;
@@ -4495,17 +4513,23 @@ static void RoadDemo(void)
 		    double sdx = SgnF(dx);
 		    double sdy = SgnF(dy);
 
-		    dx -= dxi;
-		    dy -= dyi;
+		    if (dx != 0.0)
+		    {
+			dx -= dxi;
+		    }
+
+		    if (dy != 0.0)
+		    {
+			dy -= dyi;
+		    }
 
 		    if (SgnF(dx) != sdx)
 		    {
 		    	dx = 0;
-			dy = 0;
 		    }
-		    else if (SgnF(dy) != sdy)
+
+		    if (SgnF(dy) != sdy)
 		    {
-		    	dx = 0;
 		    	dy = 0;
 		    }
 		}
-- 
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