+ 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;