From e1429f383c0e259e49ab68e20c3e06c3e0dc88d6 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sun, 7 Feb 2010 12:48:11 +0000
Subject: [PATCH] Some cosmetic improvements to arrows

---
 src/Points.cpp | 52 ++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 14 deletions(-)

diff --git a/src/Points.cpp b/src/Points.cpp
index 781d440..c2837c5 100644
--- a/src/Points.cpp
+++ b/src/Points.cpp
@@ -93,43 +93,67 @@ void Points::renderArrow() const
     glEnable(GL_BLEND);
 
     glTranslatef(-0.5f, 0.11f, 0.0f);
-    glColor4f(0.1f, 0.1f, 0.8f, 0.6f);
+    glColor4f(0.2f, 0.1f, 0.9f, 0.7f);
+
+    const float headWidth = 0.25f;
     
     if (state == TAKEN) {
-	//glRotatef(45.0f, 0.0f, 1.0f, 0.0f);
-
+	
 	const BezierCurve<float>& curve =
 	    reflected ? myReflectedCurve : myCurve;
 
 	const float step = 0.1f;
+	const float arrowLen = 0.7f;
 
-	for (float t = 0.0f; t < 1.0f; t += step) {
+	for (float t = 0.0f; t < arrowLen; t += step) {
 
 	    const Vector<float> v1 = curve(t);
 	    const Vector<float> v2 = curve(t + step);
 
 	    glDisable(GL_CULL_FACE);
 
-	    glBegin(GL_QUADS);
-	    {
-		glVertex3f(v1.x, 0.0f, v1.y - 0.1f);
-		glVertex3f(v1.x, 0.0f, v1.y + 0.1f);
-		glVertex3f(v2.x, 0.0f, v2.y + 0.1f);
-		glVertex3f(v2.x, 0.0f, v2.y - 0.1f);
+	    if (t >= arrowLen - step) {
+		// Arrow head
+		glBegin(GL_TRIANGLES);
+		{
+		    glVertex3f(v1.x, 0.0f, v1.y - headWidth);
+		    glVertex3f(v2.x, 0.0f, v2.y);
+		    glVertex3f(v1.x, 0.0f, v1.y + headWidth);
+		}
+		glEnd();
+	    }
+	    else {
+		glBegin(GL_QUADS);
+		{
+		    glVertex3f(v1.x, 0.0f, v1.y - 0.1f);
+		    glVertex3f(v1.x, 0.0f, v1.y + 0.1f);
+		    glVertex3f(v2.x, 0.0f, v2.y + 0.1f);
+		    glVertex3f(v2.x, 0.0f, v2.y - 0.1f);
+		}
+		glEnd();
 	    }
-	    glEnd();
-
 	}
     }
     else {
+	const float headLength = 0.3f;
+	
 	glBegin(GL_QUADS);
 	{
 	    glVertex3f(0.0f, 0.0f, 0.1f);
-	    glVertex3f(3.0f, 0.0f, 0.1f);
-	    glVertex3f(3.0f, 0.0f, -0.1f);
+	    glVertex3f(2.0f - headLength, 0.0f, 0.1f);
+	    glVertex3f(2.0f - headLength, 0.0f, -0.1f);
 	    glVertex3f(0.0f, 0.0f, -0.1f);
 	}
 	glEnd();
+	
+	// Draw the arrow head
+	glBegin(GL_TRIANGLES);
+	{
+	    glVertex3f(2.0f - headLength, 0.0f, headWidth);
+	    glVertex3f(2.0f, 0.0f, 0.0f);
+	    glVertex3f(2.0f - headLength, 0.0f, -headWidth);
+	}
+	glEnd();
     }
 
     glPopAttrib();
-- 
2.39.2