-/* sphere, Copyright (c) 1998 David Konerding <dek@cgl.ucsf.edu>
+/* sphere, Copyright (c) 2002 Paul Bourke <pbourke@swin.edu.au>,
+ * Copyright (c) 2010-2014 Jamie Zawinski <jwz@jwz.org>
* Utility function to create a unit sphere in GL.
*
* Permission to use, copy, modify, distribute, and sell this software and its
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
- * 8-Oct-98: dek Released initial version of "glplanet"
- * 21-Mar-01: jwz@jwz.org Broke sphere routine out into its own file.
+ * 8-Oct-98: dek Released initial version of "glplanet"
+ * 21-Mar-01: jwz@jwz.org Broke sphere routine out into its own file.
+ * 28-Feb-02: jwz@jwz.org New implementation from Paul Bourke:
+ * http://astronomy.swin.edu.au/~pbourke/opengl/sphere/
+ * 21-Aug-10 jwz@jwz.org Converted to use glDrawArrays, for OpenGL ES.
*/
-#include "config.h"
-#include <stdlib.h>
#include <math.h>
-#include <GL/glx.h>
-#include "tube.h"
+#include <stdlib.h>
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifndef HAVE_COCOA
+# include <GL/gl.h>
+#endif
+
+#ifdef HAVE_JWZGLES
+# include "jwzgles.h"
+#endif /* HAVE_JWZGLES */
-/* Function for determining points on the surface of the sphere */
-static void
-parametric_sphere (float theta, float rho, GLfloat *vector)
+#include "sphere.h"
+
+typedef struct { GLfloat x, y, z; } XYZ;
+
+static int
+unit_sphere_1 (int stacks, int slices, int wire_p, int half_p)
{
- vector[0] = -sin(theta) * sin(rho);
- vector[1] = cos(theta) * sin(rho);
- vector[2] = cos(rho);
+ int polys = 0;
+ int i,j;
+ double theta1, theta2, theta3;
+ XYZ p, n;
+ XYZ la = { 0, -1, 0 }, lb = { 0, -1, 0 };
+ XYZ c = {0, 0, 0}; /* center */
+ double r = 1.0; /* radius */
+ int stacks2 = stacks * 2;
+ int end = (half_p ? stacks/2 : stacks);
+
+ int mode = (wire_p ? GL_LINE_STRIP : GL_TRIANGLE_STRIP);
+
+ int arraysize, out;
+ struct { XYZ p; XYZ n; GLfloat s, t; } *array;
+
+ if (r < 0)
+ r = -r;
+ if (slices < 0)
+ slices = -slices;
+
+ arraysize = (stacks+1) * (slices+1) * (wire_p ? 4 : 2);
+ array = (void *) calloc (arraysize, sizeof(*array));
+ if (! array) abort();
+ out = 0;
+
+ if (slices < 4 || stacks < 2 || r <= 0)
+ {
+ mode = GL_POINTS;
+ array[out++].p = c;
+ goto END;
+ }
+
+ for (j = 0; j < end; j++)
+ {
+ theta1 = j * (M_PI+M_PI) / stacks2 - M_PI_2;
+ theta2 = (j + 1) * (M_PI+M_PI) / stacks2 - M_PI_2;
+
+ for (i = slices; i >= 0; i--)
+ {
+ theta3 = i * (M_PI+M_PI) / slices;
+
+ if (wire_p)
+ {
+ array[out++].p = lb; /* vertex */
+ array[out++].p = la; /* vertex */
+ }
+
+ n.x = cos (theta2) * cos(theta3);
+ n.y = sin (theta2);
+ n.z = cos (theta2) * sin(theta3);
+ p.x = c.x + r * n.x;
+ p.y = c.y + r * n.y;
+ p.z = c.z + r * n.z;
+
+ array[out].p = p; /* vertex */
+ array[out].n = n; /* normal */
+ array[out].s = i / (GLfloat) slices; /* texture */
+ array[out].t = 2*(j+1) / (GLfloat) stacks2;
+ out++;
+
+ if (wire_p) la = p;
+
+ n.x = cos(theta1) * cos(theta3);
+ n.y = sin(theta1);
+ n.z = cos(theta1) * sin(theta3);
+ p.x = c.x + r * n.x;
+ p.y = c.y + r * n.y;
+ p.z = c.z + r * n.z;
+
+ array[out].p = p; /* vertex */
+ array[out].n = n; /* normal */
+ array[out].s = i / (GLfloat) slices; /* texture */
+ array[out].t = 2*j / (GLfloat) stacks2;
+ out++;
+
+ if (out >= arraysize) abort();
+
+ if (wire_p) lb = p;
+ polys++;
+ }
+ }
+
+ END:
+
+ glEnableClientState (GL_VERTEX_ARRAY);
+ glEnableClientState (GL_NORMAL_ARRAY);
+ glEnableClientState (GL_TEXTURE_COORD_ARRAY);
+
+ glVertexPointer (3, GL_FLOAT, sizeof(*array), &array[0].p);
+ glNormalPointer ( GL_FLOAT, sizeof(*array), &array[0].n);
+ glTexCoordPointer (2, GL_FLOAT, sizeof(*array), &array[0].s);
+
+ glDrawArrays (mode, 0, out);
+
+ free (array);
+
+ return polys;
}
-void
-unit_sphere (int stacks, int slices, Bool wire)
+int
+unit_sphere (int stacks, int slices, int wire_p)
{
- int i, j;
- float drho, dtheta;
- float rho, theta;
- GLfloat vector[3];
- GLfloat ds, dt, t, s;
-
- if (!wire)
- glShadeModel(GL_SMOOTH);
-
- /* Generate a sphere with quadrilaterals.
- * Quad vertices are determined using a parametric sphere function.
- * For fun, you could generate practically any parameteric surface and
- * map an image onto it.
- */
- drho = M_PI / stacks;
- dtheta = 2.0 * M_PI / slices;
- ds = 1.0 / slices;
- dt = 1.0 / stacks;
-
- glFrontFace(GL_CCW);
- glBegin (wire ? GL_LINE_LOOP : GL_QUADS);
-
- t = 0.0;
- for (i=0; i < stacks; i++) {
- rho = i * drho;
- s = 0.0;
- for (j=0; j < slices; j++) {
- theta = j * dtheta;
-
- glTexCoord2f (s,t);
- parametric_sphere (theta, rho, vector);
- glNormal3fv (vector);
- parametric_sphere (theta, rho, vector);
- glVertex3f (vector[0], vector[1], vector[2]);
-
- glTexCoord2f (s,t+dt);
- parametric_sphere (theta, rho+drho, vector);
- glNormal3fv (vector);
- parametric_sphere (theta, rho+drho, vector);
- glVertex3f (vector[0], vector[1], vector[2]);
-
- glTexCoord2f (s+ds,t+dt);
- parametric_sphere (theta + dtheta, rho+drho, vector);
- glNormal3fv (vector);
- parametric_sphere (theta + dtheta, rho+drho, vector);
- glVertex3f (vector[0], vector[1], vector[2]);
-
- glTexCoord2f (s+ds, t);
- parametric_sphere (theta + dtheta, rho, vector);
- glNormal3fv (vector);
- parametric_sphere (theta + dtheta, rho, vector);
- glVertex3f (vector[0], vector[1], vector[2]);
-
- s = s + ds;
- }
- t = t + dt;
- }
- glEnd();
+ return unit_sphere_1 (stacks, slices, wire_p, 0);
+}
+
+int
+unit_dome (int stacks, int slices, int wire_p)
+{
+ return unit_sphere_1 (stacks, slices, wire_p, 1);
}
projects / xscreensaver / blobdiff