http://slackware.bholcomb.com/slackware/slackware-11.0/source/xap/xscreensaver/xscree...
[xscreensaver] / hacks / glx / stairs.c
index 5896e195a1e1792e1ad906aba0a3df92f636aca8..10f96b5f55dffa674361d1d5b94c257dbeaebb7e 100644 (file)
@@ -1,9 +1,8 @@
 /* -*- Mode: C; tab-width: 4 -*- */
 /* stairs --- Infinite Stairs, and Escher-like scene. */
 
-#if !defined( lint ) && !defined( SABER )
+#if 0
 static const char sccsid[] = "@(#)stairs.c     4.07 97/11/24 xlockmore";
-
 #endif
 
 #undef DEBUG_LISTS
@@ -33,9 +32,7 @@ static const char sccsid[] = "@(#)stairs.c    4.07 97/11/24 xlockmore";
  * Since I'm not a native English speaker, my apologies for any grammatical
  * mistake.
  *
- * My e-mail addresses are
- * vianna@cat.cbpf.br 
- *         and
+ * My e-mail address is
  * m-vianna@usa.net
  *
  * Marcelo F. Vianna (Jun-01-1997)
@@ -56,20 +53,15 @@ static const char sccsid[] = "@(#)stairs.c  4.07 97/11/24 xlockmore";
  * mapping shuld work on PseudoColor, DirectColor, TrueColor using Mesa. Mono
  * is not officially supported for both OpenGL and Mesa, but seems to not crash
  * Mesa.
-z *
+ *
  * In real OpenGL, PseudoColor DO NOT support texture map (as far as I know).
  */
 
-#include <X11/Intrinsic.h>
-
 #ifdef STANDALONE
-# define PROGCLASS                     "Stairs"
-# define HACK_INIT                     init_stairs
-# define HACK_DRAW                     draw_stairs
-# define stairs_opts           xlockmore_opts
-# define DEFAULTS                      "*cycles:               1       \n"                     \
-                                                       "*delay:                200000  \n"                     \
-                                                       "*wireframe:    False   \n"
+# define DEFAULTS                      "*delay:                20000   \n" \
+                                                       "*showFPS:      False   \n"
+# define refresh_stairs 0
+# define stairs_handle_event 0
 # include "xlockmore.h"                /* from the xscreensaver distribution */
 #else /* !STANDALONE */
 # include "xlock.h"                    /* from the xlockmore distribution */
@@ -78,17 +70,16 @@ z *
 
 #ifdef USE_GL
 
-#include <GL/glu.h>
 #include "e_textures.h"
 
-ModeSpecOpt stairs_opts =
+ENTRYPOINT ModeSpecOpt stairs_opts =
 {0, NULL, 0, NULL, NULL};
 
 #ifdef USE_MODULES
 ModStruct   stairs_description =
 {"stairs", "init_stairs", "draw_stairs", "release_stairs",
  "draw_stairs", "change_stairs", NULL, &stairs_opts,
- 1000, 1, 1, 1, 1.0, "",
+ 1000, 1, 1, 1, 4, 1.0, "",
  "Shows Infinite Stairs, an Escher-like scene", 0, NULL};
 
 #endif
@@ -108,95 +99,81 @@ typedef struct {
        GLint       WindH, WindW;
        GLfloat     step;
        Bool        direction;
-  int         AreObjectsDefined[1];
-       int     sphere_position;
+       int         AreObjectsDefined[1];
+       int         sphere_position;
+       int         sphere_tick;
        GLXContext *glx_context;
+    GLuint objects;
 } stairsstruct;
 
-static float front_shininess[] =
-{60.0};
-static float front_specular[] =
-{0.7, 0.7, 0.7, 1.0};
-static float ambient[] =
-{0.0, 0.0, 0.0, 1.0};
-static float diffuse[] =
-{1.0, 1.0, 1.0, 1.0};
-static float position0[] =
-{1.0, 1.0, 1.0, 0.0};
-static float position1[] =
-{-1.0, -1.0, 1.0, 0.0};
-static float lmodel_ambient[] =
-{0.5, 0.5, 0.5, 1.0};
-static float lmodel_twoside[] =
-{GL_TRUE};
+static const float front_shininess[] = {60.0};
+static const float front_specular[] = {0.7, 0.7, 0.7, 1.0};
+static const float ambient[] = {0.0, 0.0, 0.0, 1.0};
+static const float diffuse[] = {1.0, 1.0, 1.0, 1.0};
+static const float position0[] = {1.0, 1.0, 1.0, 0.0};
+static const float position1[] = {-1.0, -1.0, 1.0, 0.0};
+static const float lmodel_ambient[] = {0.5, 0.5, 0.5, 1.0};
+static const float lmodel_twoside[] = {GL_TRUE};
 
 #if 0
-static float MaterialRed[] =
-{0.7, 0.0, 0.0, 1.0};
-static float MaterialGreen[] =
-{0.1, 0.5, 0.2, 1.0};
-static float MaterialBlue[] =
-{0.0, 0.0, 0.7, 1.0};
-static float MaterialCyan[] =
-{0.2, 0.5, 0.7, 1.0};
-static float MaterialMagenta[] =
-{0.6, 0.2, 0.5, 1.0};
-static float MaterialGray[] =
-{0.2, 0.2, 0.2, 1.0};
-static float MaterialGray5[] =
-{0.5, 0.5, 0.5, 1.0};
-static float MaterialGray6[] =
-{0.6, 0.6, 0.6, 1.0};
-static float MaterialGray8[] =
-{0.8, 0.8, 0.8, 1.0};
+static const float MaterialRed[] = {0.7, 0.0, 0.0, 1.0};
+static const float MaterialGreen[] = {0.1, 0.5, 0.2, 1.0};
+static const float MaterialBlue[] = {0.0, 0.0, 0.7, 1.0};
+static const float MaterialCyan[] = {0.2, 0.5, 0.7, 1.0};
+static const float MaterialMagenta[] = {0.6, 0.2, 0.5, 1.0};
+static const float MaterialGray[] = {0.2, 0.2, 0.2, 1.0};
+static const float MaterialGray5[] = {0.5, 0.5, 0.5, 1.0};
+static const float MaterialGray6[] = {0.6, 0.6, 0.6, 1.0};
+static const float MaterialGray8[] = {0.8, 0.8, 0.8, 1.0};
+
 #endif
-static float MaterialYellow[] =
-{0.7, 0.7, 0.0, 1.0};
-static float MaterialWhite[] =
-{0.7, 0.7, 0.7, 1.0};
+static const float MaterialYellow[] = {0.7, 0.7, 0.0, 1.0};
+static const float MaterialWhite[] = {0.7, 0.7, 0.7, 1.0};
 
-static float positions[] =
+static const float positions[] =
 {
-  -2.5, 4.0, 0.0, /* First one is FUDGED :) */
-  -3.0, 3.25, 1.0,
-  -3.0, 4.4, 1.5,
-  -3.0, 3.05, 2.0,
-  -3.0, 4.2, 2.5,
-
-  -3.0, 2.85, 3.0,
-  -2.5, 4.0, 3.0,
-  -2.0, 2.75, 3.0,
-  -1.5, 3.9, 3.0,
-  -1.0, 2.65, 3.0,
-  -0.5, 3.8, 3.0,
-  0.0, 2.55, 3.0,
-  0.5, 3.7, 3.0,
-  1.0, 2.45, 3.0,
-  1.5, 3.6, 3.0,
-  2.0, 2.35, 3.0,
-
-  2.0, 3.5, 2.5,
-  2.0, 2.25, 2.0,
-  2.0, 3.4, 1.5,
-  2.0, 2.15, 1.0,
-  2.0, 3.3, 0.5,
-  2.0, 2.05, 0.0,
-  2.0, 3.2, -0.5,
-  2.0, 1.95, -1.0,
-  2.0, 3.1, -1.5,
-  2.0, 1.85, -2.0,
-
-  1.5, 2.9, -2.0,
-  1.0, 1.65, -2.0,
-  0.5, 2.7, -2.0,
-  0.0, 1.55, -2.0,
-  -0.5, 2.5, -2.0,
-  -1.0, 1.45, -2.0,
+       -2.5, 4.0, 0.0,         /* First one is FUDGED :) */
+       -3.0, 3.25, 1.0,
+       -3.0, 4.4, 1.5,
+       -3.0, 3.05, 2.0,
+       -3.0, 4.2, 2.5,
+
+       -3.0, 2.85, 3.0,
+       -2.5, 4.0, 3.0,
+       -2.0, 2.75, 3.0,
+       -1.5, 3.9, 3.0,
+       -1.0, 2.65, 3.0,
+       -0.5, 3.8, 3.0,
+       0.0, 2.55, 3.0,
+       0.5, 3.7, 3.0,
+       1.0, 2.45, 3.0,
+       1.5, 3.6, 3.0,
+       2.0, 2.35, 3.0,
+
+       2.0, 3.5, 2.5,
+       2.0, 2.25, 2.0,
+       2.0, 3.4, 1.5,
+       2.0, 2.15, 1.0,
+       2.0, 3.3, 0.5,
+       2.0, 2.05, 0.0,
+       2.0, 3.2, -0.5,
+       2.0, 1.95, -1.0,
+       2.0, 3.1, -1.5,
+       2.0, 1.85, -2.0,
+
+       1.5, 2.9, -2.0,
+       1.0, 1.65, -2.0,
+       0.5, 2.7, -2.0,
+       0.0, 1.55, -2.0,
+       -0.5, 2.5, -2.0,
+       -1.0, 1.45, -2.0,
 };
+
 #define NPOSITIONS ((sizeof positions) / (sizeof positions[0]))
 
+#define SPHERE_TICKS 8
+
 static stairsstruct *stairs = NULL;
-static GLuint objects;
 
 #define ObjSphere    0
 
@@ -216,124 +193,203 @@ mySphere(float radius)
 }
 
 static void
-draw_block(stairsstruct * sp, GLfloat width, GLfloat height, GLfloat thickness)
+draw_block(GLfloat width, GLfloat height, GLfloat thickness)
 {
-               glBegin(GL_QUADS);
-               glNormal3f(0, 0, 1);
-               glTexCoord2f(0, 0);
-               glVertex3f(-width, -height, thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(width, -height, thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(width, height, thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(-width, height, thickness);
-               glNormal3f(0, 0, -1);
-               glTexCoord2f(0, 0);
-               glVertex3f(-width, height, -thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(width, height, -thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(width, -height, -thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(-width, -height, -thickness);
-               glNormal3f(0, 1, 0);
-               glTexCoord2f(0, 0);
-               glVertex3f(-width, height, thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(width, height, thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(width, height, -thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(-width, height, -thickness);
-               glNormal3f(0, -1, 0);
-               glTexCoord2f(0, 0);
-               glVertex3f(-width, -height, -thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(width, -height, -thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(width, -height, thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(-width, -height, thickness);
-               glNormal3f(1, 0, 0);
-               glTexCoord2f(0, 0);
-               glVertex3f(width, -height, thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(width, -height, -thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(width, height, -thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(width, height, thickness);
-               glNormal3f(-1, 0, 0);
-               glTexCoord2f(0, 0);
-               glVertex3f(-width, height, thickness);
-               glTexCoord2f(1, 0);
-               glVertex3f(-width, height, -thickness);
-               glTexCoord2f(1, 1);
-               glVertex3f(-width, -height, -thickness);
-               glTexCoord2f(0, 1);
-               glVertex3f(-width, -height, thickness);
-               glEnd();
+       glBegin(GL_QUADS);
+       glNormal3f(0, 0, 1);
+       glTexCoord2f(0, 0);
+       glVertex3f(-width, -height, thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(width, -height, thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(width, height, thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(-width, height, thickness);
+       glNormal3f(0, 0, -1);
+       glTexCoord2f(0, 0);
+       glVertex3f(-width, height, -thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(width, height, -thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(width, -height, -thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(-width, -height, -thickness);
+       glNormal3f(0, 1, 0);
+       glTexCoord2f(0, 0);
+       glVertex3f(-width, height, thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(width, height, thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(width, height, -thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(-width, height, -thickness);
+       glNormal3f(0, -1, 0);
+       glTexCoord2f(0, 0);
+       glVertex3f(-width, -height, -thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(width, -height, -thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(width, -height, thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(-width, -height, thickness);
+       glNormal3f(1, 0, 0);
+       glTexCoord2f(0, 0);
+       glVertex3f(width, -height, thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(width, -height, -thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(width, height, -thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(width, height, thickness);
+       glNormal3f(-1, 0, 0);
+       glTexCoord2f(0, 0);
+       glVertex3f(-width, height, thickness);
+       glTexCoord2f(1, 0);
+       glVertex3f(-width, height, -thickness);
+       glTexCoord2f(1, 1);
+       glVertex3f(-width, -height, -thickness);
+       glTexCoord2f(0, 1);
+       glVertex3f(-width, -height, thickness);
+       glEnd();
 }
 
 static void
-draw_degree(stairsstruct * sp, GLfloat w, GLfloat h , GLfloat t)
-{
-  draw_block(sp, w, h, t);
-}
-
-static void
-draw_stairs_internal(ModeInfo *mi)
+draw_stairs_internal(ModeInfo * mi)
 {
        stairsstruct *sp = &stairs[MI_SCREEN(mi)];
-  GLfloat X;
-  
-  glPushMatrix();
-  glPushMatrix();
-  glTranslatef(-3.0, 0.1, 2.0);
-  for (X=0; X< 2; X++) {
-    draw_degree(sp, 0.5, 2.7+0.1*X, 0.5);
-    glTranslatef( 0.0, 0.1,-1.0);
-  }
+       GLfloat     X;
+
+       glPushMatrix();
+       glPushMatrix();
+       glTranslatef(-3.0, 0.1, 2.0);
+       for (X = 0; X < 2; X++) {
+               draw_block(0.5, 2.7 + 0.1 * X, 0.5);
+               glTranslatef(0.0, 0.1, -1.0);
+       }
+       glPopMatrix();
+       glTranslatef(-3.0, 0.0, 3.0);
+       glPushMatrix();
+
+       for (X = 0; X < 6; X++) {
+               draw_block(0.5, 2.6 - 0.1 * X, 0.5);
+               glTranslatef(1.0, -0.1, 0.0);
+       }
+       glTranslatef(-1.0, -0.9, -1.0);
+       for (X = 0; X < 5; X++) {
+               draw_block(0.5, 3.0 - 0.1 * X, 0.5);
+               glTranslatef(0.0, 0.0, -1.0);
+       }
+       glTranslatef(-1.0, -1.1, 1.0);
+       for (X = 0; X < 3; X++) {
+               draw_block(0.5, 3.5 - 0.1 * X, 0.5);
+               glTranslatef(-1.0, -0.1, 0.0);
+       }
        glPopMatrix();
-  glTranslatef(-3.0, 0.0, 3.0);
-  glPushMatrix();
-
-  for (X=0; X< 6; X++) {
-    draw_degree(sp, 0.5, 2.6-0.1*X, 0.5);
-    glTranslatef( 1.0,-0.1, 0.0);
-  }
-  glTranslatef(-1.0,-0.9,-1.0);
-  for (X=0; X< 5; X++) {
-    draw_degree(sp, 0.5, 3.0-0.1*X, 0.5);
-    glTranslatef( 0.0, 0.0,-1.0);
-  }
-  glTranslatef(-1.0,-1.1, 1.0);
-  for (X=0; X< 3; X++) {
-    draw_degree(sp, 0.5, 3.5-0.1*X, 0.5);
-    glTranslatef(-1.0,-0.1, 0.0);
-  }
        glPopMatrix();
+
+       glPushMatrix();
+       glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialYellow);
+
+    {
+      int pos  = sp->sphere_position;
+      int ppos = sp->sphere_position - 3;
+      int npos = sp->sphere_position + 3;
+      GLfloat spx, spy, spz;
+      GLfloat dx, dy, dz;
+      int div;
+
+      if (ppos < 0) ppos += NPOSITIONS;
+      if (npos >= NPOSITIONS) npos -= NPOSITIONS;
+
+      if (sp->sphere_tick < 0)
+        {
+          dx = positions[ppos]   - positions[pos];
+          dy = positions[ppos+1] - positions[pos+1];
+          dz = positions[ppos+2] - positions[pos+2];
+          div = SPHERE_TICKS + sp->sphere_tick;
+        }
+      else
+        {
+          dx = positions[npos]   - positions[pos];
+          dy = positions[npos+1] - positions[pos+1];
+          dz = positions[npos+2] - positions[ppos+2];
+          div = SPHERE_TICKS - sp->sphere_tick;
+        }
+        
+      spx = positions[pos];
+      spy = positions[pos+1];
+      spz = positions[pos+2];
+      if (div != 0)
+        {
+          spx += dx / div;
+          spy += dy / div;
+          spz += dz / div;
+        }
+
+
+      spy -= 0.5;   /* move the bottom of the ball closer to the stairs */
+
+
+#ifdef DEBUG
+      fprintf(stderr, "%3d %3d   %2.2f %2.2f %2.2f  %2.2f %2.2f %2.2f\n",
+              sp->sphere_position, sp->sphere_tick,
+              dx, dy, dz,
+              spx, spy, spz);
+
+      glBegin(GL_LINE_LOOP);   /* path 1 */
+      glVertex3f(positions[pos],  positions[pos+1],  positions[pos+2]);
+      glVertex3f(positions[npos], positions[npos+1], positions[npos+2]);
+      glEnd();
+
+      glBegin(GL_LINE_LOOP);   /* path 2 */
+      glVertex3f(positions[pos],  positions[pos+1],  positions[pos+2]);
+      glVertex3f(positions[ppos], positions[ppos+1], positions[ppos+2]);
+      glEnd();
+
+      glBegin(GL_LINE_LOOP);  /* base origin */
+      glVertex3f(positions[pos], positions[pos+1]-10, positions[pos+2]);
+      glVertex3f(positions[pos], positions[pos+1]+10, positions[pos+2]);
+      glEnd();
+
+      glBegin(GL_LINE_LOOP);  /* base origin */
+      glVertex3f(positions[pos]-10, positions[pos+1], positions[pos+2]);
+      glVertex3f(positions[pos]+10, positions[pos+1], positions[pos+2]);
+      glEnd();
+
+      glBegin(GL_LINE_LOOP);  /* base origin */
+      glVertex3f(positions[pos], positions[pos+1], positions[pos+2]-10);
+      glVertex3f(positions[pos], positions[pos+1], positions[pos+2]+10);
+      glEnd();
+#endif /* DEBUG */
+
+      glTranslatef(spx, spy, spz);
+
+#ifdef DEBUG  /* ball origin */
+      glBegin(GL_LINE_LOOP); glVertex3f(0,-2,0); glVertex3f(0,2,0); glEnd();
+      glBegin(GL_LINE_LOOP); glVertex3f(-2,0,0); glVertex3f(2,0,0); glEnd();
+      glBegin(GL_LINE_LOOP); glVertex3f(0,0,-2); glVertex3f(0,0,2); glEnd();
+#endif /* DEBUG */
+    }
+
+       if (sp->sphere_position == 0)   /* FUDGE soo its not so obvious */
+               mySphere(0.48);
+       else
+               mySphere(0.5);
        glPopMatrix();
 
-  glPushMatrix();
-  glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialYellow);
-
-  glTranslatef((GLfloat) positions[sp->sphere_position],
-       (GLfloat) positions[sp->sphere_position + 1],
-       (GLfloat) positions[sp->sphere_position + 2]);
-  if (sp->sphere_position == 0) /* FUDGE soo its not so obvious */
-     mySphere(0.48);
-   else
-     mySphere(0.5);
-  glPopMatrix();
-  sp->sphere_position += 3;
-  if (sp->sphere_position >= NPOSITIONS)
-    sp->sphere_position = 0;
+    if (++sp->sphere_tick >= SPHERE_TICKS-1)
+      {
+        sp->sphere_tick = -(SPHERE_TICKS-2);
+        sp->sphere_position += 3;
+        sp->sphere_position += 3;
+      }
+
+       if (sp->sphere_position >= NPOSITIONS)
+               sp->sphere_position = 0;
 }
 
-static void
-reshape(ModeInfo * mi, int width, int height)
+ENTRYPOINT void
+reshape_stairs (ModeInfo * mi, int width, int height)
 {
        stairsstruct *sp = &stairs[MI_SCREEN(mi)];
 
@@ -355,10 +411,9 @@ reshape(ModeInfo * mi, int width, int height)
 }
 
 static void
-pinit(ModeInfo * mi)
+pinit(void)
 {
-/*     stairsstruct *sp = &stairs[MI_SCREEN(mi)];*/
-
+    int status;
        glClearDepth(1.0);
        glClearColor(0.0, 0.0, 0.0, 1.0);
 
@@ -377,15 +432,28 @@ pinit(ModeInfo * mi)
        glFrontFace(GL_CCW);
        glCullFace(GL_BACK);
 
-  glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
+       glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
        glShadeModel(GL_FLAT);
        glEnable(GL_DEPTH_TEST);
        glEnable(GL_TEXTURE_2D);
        glEnable(GL_CULL_FACE);
 
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-       gluBuild2DMipmaps(GL_TEXTURE_2D, 3, WoodTextureWidth, WoodTextureHeight,
-                         GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
+
+    clear_gl_error();
+    status = gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
+                               WoodTextureWidth, WoodTextureHeight,
+                               GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
+    if (status)
+      {
+        const char *s = (char *) gluErrorString (status);
+        fprintf (stderr, "%s: error mipmapping %dx%d texture: %s\n",
+                 progname, WoodTextureWidth, WoodTextureHeight,
+                 (s ? s : "(unknown)"));
+        exit (1);
+      }
+    check_gl_error("mipmapping");
+
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
@@ -396,8 +464,8 @@ pinit(ModeInfo * mi)
        glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
 }
 
-void
-init_stairs(ModeInfo * mi)
+ENTRYPOINT void
+init_stairs (ModeInfo * mi)
 {
        int         screen = MI_SCREEN(mi);
        stairsstruct *sp;
@@ -409,23 +477,28 @@ init_stairs(ModeInfo * mi)
        }
        sp = &stairs[screen];
        sp->step = 0.0;
-  sp->direction = LRAND() & 1;
+
+    /* make multiple screens rotate at slightly different rates. */
+    sp->step -= frand(5.0);
+
+       sp->direction = LRAND() & 1;
        sp->sphere_position = NRAND(NPOSITIONS / 3) * 3;
+       sp->sphere_tick = 0;
 
        if ((sp->glx_context = init_GL(mi)) != NULL) {
 
-               reshape(mi, MI_WIN_WIDTH(mi), MI_WIN_HEIGHT(mi));
+               reshape_stairs(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
                glDrawBuffer(GL_BACK);
-               if (!glIsList(objects))
-                       objects = glGenLists(1);
-               pinit(mi);
+               if (!glIsList(sp->objects))
+                       sp->objects = glGenLists(1);
+               pinit();
        } else {
-    MI_CLEARWINDOW(mi);
+               MI_CLEARWINDOW(mi);
        }
 }
 
-void
-draw_stairs(ModeInfo * mi)
+ENTRYPOINT void
+draw_stairs (ModeInfo * mi)
 {
        stairsstruct *sp = &stairs[MI_SCREEN(mi)];
 
@@ -443,23 +516,24 @@ draw_stairs(ModeInfo * mi)
 
        glTranslatef(0.0, 0.0, -10.0);
 
-       if (!MI_WIN_IS_ICONIC(mi)) {
+       if (!MI_IS_ICONIC(mi)) {
                glScalef(Scale4Window * sp->WindH / sp->WindW, Scale4Window, Scale4Window);
        } else {
                glScalef(Scale4Iconic * sp->WindH / sp->WindW, Scale4Iconic, Scale4Iconic);
        }
 
        glRotatef(44.5, 1, 0, 0);
-  glRotatef(50 + ((sp->direction) ? 1 : -1 ) *
-     ((sp->step * 100 > 120) ? sp->step * 100 - 120 : 0), 0, 1, 0);
-  if (sp->step * 100 >= 360 + 120) {  /* stop showing secrets */
-    sp->step = 0;
-    sp->direction = LRAND() & 1;
-  }
-  draw_stairs_internal(mi);
+       glRotatef(50 + ((sp->direction) ? 1 : -1) *
+              ((sp->step * 100 > 120) ? sp->step * 100 - 120 : 0), 0, 1, 0);
+       if (sp->step * 100 >= 360 + 120) {      /* stop showing secrets */
+               sp->step = 0;
+               sp->direction = LRAND() & 1;
+       }
+       draw_stairs_internal(mi);
 
        glPopMatrix();
 
+    if (mi->fps_p) do_fps (mi);
        glFlush();
 
        glXSwapBuffers(display, window);
@@ -467,8 +541,9 @@ draw_stairs(ModeInfo * mi)
        sp->step += 0.025;
 }
 
-void
-change_stairs(ModeInfo * mi)
+#ifndef STANDALONE
+ENTRYPOINT void
+change_stairs (ModeInfo * mi)
 {
        stairsstruct *sp = &stairs[MI_SCREEN(mi)];
 
@@ -476,20 +551,27 @@ change_stairs(ModeInfo * mi)
                return;
 
        glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(sp->glx_context));
-       pinit(mi);
+       pinit();
 }
+#endif /* !STANDALONE */
 
-void
-release_stairs(ModeInfo * mi)
+ENTRYPOINT void
+release_stairs (ModeInfo * mi)
 {
        if (stairs != NULL) {
-               (void) free((void *) stairs);
-               stairs = NULL;
-       }
-       if (glIsList(objects)) {
-               glDeleteLists(objects, 1);
+      int i;
+      for (i = 0; i < MI_NUM_SCREENS(mi); i++) {
+        stairsstruct *sp = &stairs[i];
+        if (glIsList(sp->objects)) {
+          glDeleteLists(sp->objects, 1);
+        }
+      }
+      free(stairs);
+      stairs = NULL;
        }
        FreeAllGL(mi);
 }
 
+XSCREENSAVER_MODULE ("Stairs", stairs)
+
 #endif