http://www.uw-madison.lkams.kernel.org/pub/mirrors/fink/distfiles/xscreensaver-4...

[xscreensaver] / hacks / glx / tube.c

diff --git a/hacks/glx/tube.c b/hacks/glx/tube.c
index 6632c29d6882ec641a2e565f507b195974e3b5b4..20f51ed4d2839e165a4266747f4d3f7a6e6e675d 100644 (file)
--- a/hacks/glx/tube.c
+++ b/hacks/glx/tube.c
@@ -1,4 +1,4 @@
-/* tube, Copyright (c) 2001 Jamie Zawinski <jwz@jwz.org>
+/* tube, Copyright (c) 2001, 2003 Jamie Zawinski <jwz@jwz.org>
  * Utility functions to create tubes and cones in GL.
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
@@ -17,13 +17,13 @@
 #include "tube.h"
 
 static void
-unit_tube (int faces, Bool smooth, Bool wire)
+unit_tube (int faces, Bool smooth, Bool caps_p, Bool wire)
 {
   int i;
   GLfloat step = M_PI * 2 / faces;
   GLfloat s2 = step/2;
   GLfloat th;
-  GLfloat x, y, x0, y0;
+  GLfloat x, y, x0=0, y0=0;
   int z = 0;
 
   /* side walls
@@ -70,26 +70,27 @@ unit_tube (int faces, Bool smooth, Bool wire)
 
   /* End caps
    */
-  for (z = 0; z <= 1; z++)
-    {
-      glFrontFace(z == 0 ? GL_CCW : GL_CW);
-      glNormal3f(0, (z == 0 ? -1 : 1), 0);
-      glBegin(wire ? GL_LINE_LOOP : GL_TRIANGLE_FAN);
-      if (! wire) glVertex3f(0, z, 0);
-      for (i = 0, th = 0; i <= faces; i++)
-        {
-          GLfloat x = cos (th);
-          GLfloat y = sin (th);
-          glVertex3f(x, z, y);
-          th += step;
-        }
-      glEnd();
-    }
+  if (caps_p)
+    for (z = 0; z <= 1; z++)
+      {
+        glFrontFace(z == 0 ? GL_CCW : GL_CW);
+        glNormal3f(0, (z == 0 ? -1 : 1), 0);
+        glBegin(wire ? GL_LINE_LOOP : GL_TRIANGLE_FAN);
+        if (! wire) glVertex3f(0, z, 0);
+        for (i = 0, th = 0; i <= faces; i++)
+          {
+            GLfloat x = cos (th);
+            GLfloat y = sin (th);
+            glVertex3f(x, z, y);
+            th += step;
+          }
+        glEnd();
+      }
 }
 
 
 static void
-unit_cone (int faces, Bool smooth, Bool wire)
+unit_cone (int faces, Bool smooth, Bool cap_p, Bool wire)
 {
   int i;
   GLfloat step = M_PI * 2 / faces;
@@ -129,18 +130,21 @@ unit_cone (int faces, Bool smooth, Bool wire)
 
   /* End cap
    */
-  glFrontFace(GL_CCW);
-  glNormal3f(0, -1, 0);
-  glBegin(wire ? GL_LINE_LOOP : GL_TRIANGLE_FAN);
-  if (! wire) glVertex3f(0, 0, 0);
-  for (i = 0, th = 0; i <= faces; i++)
+  if (cap_p)
     {
-      GLfloat x = cos (th);
-      GLfloat y = sin (th);
-      glVertex3f(x, 0, y);
-      th += step;
+      glFrontFace(GL_CCW);
+      glNormal3f(0, -1, 0);
+      glBegin(wire ? GL_LINE_LOOP : GL_TRIANGLE_FAN);
+      if (! wire) glVertex3f(0, 0, 0);
+      for (i = 0, th = 0; i <= faces; i++)
+        {
+          GLfloat x = cos (th);
+          GLfloat y = sin (th);
+          glVertex3f(x, 0, y);
+          th += step;
+        }
+      glEnd();
     }
-  glEnd();
 }
 
 
@@ -148,31 +152,28 @@ static void
 tube_1 (GLfloat x1, GLfloat y1, GLfloat z1,
         GLfloat x2, GLfloat y2, GLfloat z2,
         GLfloat diameter, GLfloat cap_size,
-        int faces, Bool smooth, Bool wire,
+        int faces, Bool smooth, Bool caps_p, Bool wire,
         Bool cone_p)
 {
-  GLfloat length, angle, a, b, c;
+  GLfloat length, X, Y, Z;
 
   if (diameter <= 0) abort();
 
-  a = (x2 - x1);
-  b = (y2 - y1);
-  c = (z2 - z1);
+  X = (x2 - x1);
+  Y = (y2 - y1);
+  Z = (z2 - z1);
 
-  length = sqrt (a*a + b*b + c*c);
-  angle = acos (a / length);
+  if (X == 0 && Y == 0 && Z == 0)
+    return;
 
-  glPushMatrix();
-  glTranslatef(x1, y1, z1);
-  glScalef (length, length, length);
+  length = sqrt (X*X + Y*Y + Z*Z);
 
-  if (c == 0 && b == 0)
-    glRotatef (angle / (M_PI / 180), 0, 1, 0);
-  else
-    glRotatef (angle / (M_PI / 180), 0, -c, b);
+  glPushMatrix();
 
-  glRotatef (-90, 0, 0, 1);
-  glScalef (diameter/length, 1, diameter/length);
+  glTranslatef(x1, y1, z1);
+  glRotatef (-atan2 (X, Y)               * (180 / M_PI), 0, 0, 1);
+  glRotatef ( atan2 (Z, sqrt(X*X + Y*Y)) * (180 / M_PI), 1, 0, 0);
+  glScalef (diameter, length, diameter);
 
   /* extend the endpoints of the tube by the cap size in both directions */
   if (cap_size != 0)
@@ -183,9 +184,10 @@ tube_1 (GLfloat x1, GLfloat y1, GLfloat z1,
     }
 
   if (cone_p)
-    unit_cone (faces, smooth, wire);
+    unit_cone (faces, smooth, caps_p, wire);
   else
-    unit_tube (faces, smooth, wire);
+    unit_tube (faces, smooth, caps_p, wire);
+
   glPopMatrix();
 }
 
@@ -194,9 +196,10 @@ void
 tube (GLfloat x1, GLfloat y1, GLfloat z1,
       GLfloat x2, GLfloat y2, GLfloat z2,
       GLfloat diameter, GLfloat cap_size,
-      int faces, Bool smooth, Bool wire)
+      int faces, Bool smooth, Bool caps_p, Bool wire)
 {
-  tube_1 (x1, y1, z1, x2, y2, z2, diameter, cap_size, faces, smooth, wire,
+  tube_1 (x1, y1, z1, x2, y2, z2, diameter, cap_size,
+          faces, smooth, caps_p, wire,
           False);
 }
 
@@ -205,8 +208,9 @@ void
 cone (GLfloat x1, GLfloat y1, GLfloat z1,
       GLfloat x2, GLfloat y2, GLfloat z2,
       GLfloat diameter, GLfloat cap_size,
-      int faces, Bool smooth, Bool wire)
+      int faces, Bool smooth, Bool cap_p, Bool wire)
 {
-  tube_1 (x1, y1, z1, x2, y2, z2, diameter, cap_size, faces, smooth, wire,
+  tube_1 (x1, y1, z1, x2, y2, z2, diameter, cap_size,
+          faces, smooth, cap_p, wire,
           True);
 }