+static void fghTorus( double dInnerRadius, double dOuterRadius, GLint nSides, GLint nRings, GLboolean useWireMode )
+{
+ int i,j,idx, nVert;
+ GLfloat *vertices, *normals;
+
+ /* Generate vertices and normals */
+ fghGenerateTorus((GLfloat)dInnerRadius,(GLfloat)dOuterRadius,nSides,nRings, &vertices,&normals,&nVert);
+
+ if (nVert==0)
+ /* nothing to draw */
+ return;
+
+ if (useWireMode)
+ {
+ GLushort *sideIdx, *ringIdx;
+ /* First, generate vertex index arrays for drawing with glDrawElements
+ * We have a bunch of line_loops to draw each side, and a
+ * bunch for each ring.
+ */
+
+ ringIdx = malloc(nRings*nSides*sizeof(GLushort));
+ sideIdx = malloc(nSides*nRings*sizeof(GLushort));
+ if (!(ringIdx) || !(sideIdx))
+ {
+ free(ringIdx);
+ free(sideIdx);
+ fgError("Failed to allocate memory in fghTorus");
+ }
+
+ /* generate for each ring */
+ for( j=0,idx=0; j<nRings; j++ )
+ for( i=0; i<nSides; i++, idx++ )
+ ringIdx[idx] = j * nSides + i;
+
+ /* generate for each side */
+ for( i=0,idx=0; i<nSides; i++ )
+ for( j=0; j<nRings; j++, idx++ )
+ sideIdx[idx] = j * nSides + i;
+
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
+
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ /*draw rings*/
+ for( i=0; i<nSides; i++ )
+ glDrawElements(GL_LINE_LOOP,nRings,GL_UNSIGNED_SHORT,ringIdx+i*nRings);
+ /*draw sides*/
+ for (i=0; i<nRings; i++)
+ glDrawElements(GL_LINE_LOOP,nSides,GL_UNSIGNED_SHORT,sideIdx+i*nSides);
+
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
+
+ /* cleanup allocated memory */
+ free(sideIdx);
+ free(ringIdx);
+ }
+ else
+ {
+ /* clearly, this branch is TODO */
+ /* First, generate vertex index arrays for drawing with glDrawElements
+ * All stacks, including top and bottom are covered with a triangle
+ * strip.
+ */
+ GLushort *stripIdx;
+
+ /* Allocate buffers for indices, bail out if memory allocation fails */
+ stripIdx = malloc((nRings+1)*2*nSides*sizeof(GLushort));
+ if (!(stripIdx))
+ {
+ free(stripIdx);
+ fgError("Failed to allocate memory in fghTorus");
+ }
+
+ for( i=0, idx=0; i<nSides; i++ )
+ {
+ int ioff = 1;
+ if (i==nSides-1)
+ ioff = -i;
+
+ for( j=0; j<nRings; j++, idx+=2 )
+ {
+ int offset = j * nSides + i;
+ stripIdx[idx ] = offset;
+ stripIdx[idx+1] = offset + ioff;
+ }
+ /* repeat first to close off shape */
+ stripIdx[idx ] = i;
+ stripIdx[idx+1] = i + ioff;
+ idx +=2;
+ }
+
+ /* draw */
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_NORMAL_ARRAY);
+
+ glVertexPointer(3, GL_FLOAT, 0, vertices);
+ glNormalPointer(GL_FLOAT, 0, normals);
+ for (i=0; i<nSides; i++)
+ glDrawElements(GL_TRIANGLE_STRIP,(nRings+1)*2,GL_UNSIGNED_SHORT,stripIdx+i*(nRings+1)*2);
+
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_NORMAL_ARRAY);
+
+ /* cleanup allocated memory */
+ free(stripIdx);
+ }
+
+ /* cleanup allocated memory */
+ free(vertices);
+ free(normals);
+}
+