/* -- INTERNAL SETUP OF GEOMETRY --------------------------------------- */
-/* -- first the cachable ones -- */
+static unsigned int ipow (int x, unsigned int y)
+{
+ return y==0? 1: y==1? x: (y%2? x: 1) * ipow(x*x, y/2);
+}
/* Magic Numbers: r0 = ( 1, 0, 0 )
* r1 = ( -1/3, 2 sqrt(2) / 3, 0 )
* Normals: The unit normals are simply the negative of the coordinates of the point not on the surface.
*/
-/* -- TetraHedron -- */
+/* -- Tetrahedron -- */
#define TETR_NUM_FACES 4
#define TETR_NUM_VERT_PER_FACE 3
+#define TETR_VERT_PER_TETR TETR_NUM_FACES*TETR_NUM_VERT_PER_FACE
+#define TETR_VERT_ELEM_PER_TETR TETR_VERT_PER_TETR*3
/* Vertex Coordinates */
static GLdouble tet_r[TETR_NUM_FACES][TETR_NUM_VERT_PER_FACE] =
/* Cache of input to glDrawArrays */
static GLboolean tetrCached = FALSE;
-static double tetr_verts[TETR_NUM_FACES * TETR_NUM_VERT_PER_FACE * 3];
-static double tetr_norms[TETR_NUM_FACES * TETR_NUM_VERT_PER_FACE * 3];
+static double tetr_verts[TETR_VERT_ELEM_PER_TETR];
+static double tetr_norms[TETR_VERT_ELEM_PER_TETR];
-static void fghTetrahedronCache()
+static void fghTetrahedronGenerate()
{
- int p,q;
+ int i,j;
/*
* Build array with vertices from vertex coordinates and vertex indices
* Do same for normals.
* Need to do this because of different normals at shared vertices
* (and because normals' coordinates need to be negated).
*/
- for (p=0; p<TETR_NUM_FACES; p++)
+ for (i=0; i<TETR_NUM_FACES; i++)
{
- for (q=0; q<TETR_NUM_VERT_PER_FACE; q++)
+ for (j=0; j<TETR_NUM_VERT_PER_FACE; j++)
{
- int idx = p*TETR_NUM_VERT_PER_FACE*3+q*3;
- tetr_verts[idx ] = tet_r[tet_i[p][q]][0];
- tetr_verts[idx+1] = tet_r[tet_i[p][q]][1];
- tetr_verts[idx+2] = tet_r[tet_i[p][q]][2];
-
- tetr_norms[idx ] = -tet_r[tet_n[p]][0];
- tetr_norms[idx+1] = -tet_r[tet_n[p]][1];
- tetr_norms[idx+2] = -tet_r[tet_n[p]][2];
+ int idx = i*TETR_NUM_VERT_PER_FACE*3+j*3;
+ tetr_verts[idx ] = tet_r[tet_i[i][j]][0];
+ tetr_verts[idx+1] = tet_r[tet_i[i][j]][1];
+ tetr_verts[idx+2] = tet_r[tet_i[i][j]][2];
+
+ tetr_norms[idx ] = -tet_r[tet_n[i]][0];
+ tetr_norms[idx+1] = -tet_r[tet_n[i]][1];
+ tetr_norms[idx+2] = -tet_r[tet_n[i]][2];
+ }
+ }
+}
+
+/* -- Sierpinski Sponge -- */
+static void fghSierpinskiSpongeGenerate ( int numLevels, GLdouble offset[3], GLdouble scale, double* vertices, double* normals )
+{
+ int i, j;
+ if ( numLevels == 0 )
+ {
+ for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
+ {
+ for ( j = 0; j < TETR_NUM_VERT_PER_FACE; j++ )
+ {
+ int idx = i*TETR_NUM_VERT_PER_FACE*3+j*3;
+ vertices[idx ] = offset[0] + scale * tet_r[tet_i[i][j]][0];
+ vertices[idx+1] = offset[1] + scale * tet_r[tet_i[i][j]][1];
+ vertices[idx+2] = offset[2] + scale * tet_r[tet_i[i][j]][2];
+
+ normals[idx ] = -tet_r[tet_n[i]][0];
+ normals[idx+1] = -tet_r[tet_n[i]][1];
+ normals[idx+2] = -tet_r[tet_n[i]][2];
+ }
+ }
+ }
+ else if ( numLevels > 0 )
+ {
+ GLdouble local_offset[3] ; /* Use a local variable to avoid buildup of roundoff errors */
+ unsigned int stride = ipow(4,--numLevels)*TETR_VERT_ELEM_PER_TETR;
+ scale /= 2.0 ;
+ for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
+ {
+ local_offset[0] = offset[0] + scale * tet_r[i][0];
+ local_offset[1] = offset[1] + scale * tet_r[i][1];
+ local_offset[2] = offset[2] + scale * tet_r[i][2];
+ fghSierpinskiSpongeGenerate ( numLevels, local_offset, scale, vertices+i*stride, normals+i*stride );
}
}
}
static void fghTetrahedron( GLboolean useWireMode )
{
if (!tetrCached)
- fghTetrahedronCache();
+ fghTetrahedronGenerate();
- fghDrawGeometry(GL_TRIANGLES,tetr_verts,tetr_norms,TETR_NUM_FACES*TETR_NUM_VERT_PER_FACE,useWireMode);
+ fghDrawGeometry(GL_TRIANGLES,tetr_verts,tetr_norms,TETR_VERT_PER_TETR,useWireMode);
+}
+
+static void fghSierpinskiSponge ( int numLevels, GLdouble offset[3], GLdouble scale, GLboolean useWireMode )
+{
+ double *vertices;
+ double * normals;
+ unsigned int numTetr = numLevels<0? 0 : ipow(4,numLevels); /* No sponge for numLevels below 0 */
+ unsigned int numVert = numTetr*TETR_VERT_PER_TETR;
+
+ if (numTetr)
+ {
+ /* Allocate memory */
+ vertices = malloc(numVert*3 * sizeof(double));
+ normals = malloc(numVert*3 * sizeof(double));
+
+ /* Generate elements */
+ fghSierpinskiSpongeGenerate ( numLevels, offset, scale, vertices, normals );
+
+ /* Draw and cleanup */
+ fghDrawGeometry(GL_TRIANGLES,vertices,normals,numVert,useWireMode);
+ free(vertices);
+ free(normals );
+ }
}
glEnd () ;
}
-void FGAPIENTRY glutWireSierpinskiSponge ( int num_levels, GLdouble offset[3], GLdouble scale )
-{
- int i, j ;
-
- FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutWireSierpinskiSponge" );
-
- if ( num_levels == 0 )
- {
-
- for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
- {
- glBegin ( GL_LINE_LOOP ) ;
- glNormal3d ( -tet_r[i][0], -tet_r[i][1], -tet_r[i][2] ) ;
- for ( j = 0; j < 3; j++ )
- {
- double x = offset[0] + scale * tet_r[tet_i[i][j]][0] ;
- double y = offset[1] + scale * tet_r[tet_i[i][j]][1] ;
- double z = offset[2] + scale * tet_r[tet_i[i][j]][2] ;
- glVertex3d ( x, y, z ) ;
- }
-
- glEnd () ;
- }
- }
- else if ( num_levels > 0 )
- {
- GLdouble local_offset[3] ; /* Use a local variable to avoid buildup of roundoff errors */
- num_levels -- ;
- scale /= 2.0 ;
- for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
- {
- local_offset[0] = offset[0] + scale * tet_r[i][0] ;
- local_offset[1] = offset[1] + scale * tet_r[i][1] ;
- local_offset[2] = offset[2] + scale * tet_r[i][2] ;
- glutWireSierpinskiSponge ( num_levels, local_offset, scale ) ;
- }
- }
-}
-
-void FGAPIENTRY glutSolidSierpinskiSponge ( int num_levels, GLdouble offset[3], GLdouble scale )
-{
- int i, j ;
-
- FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidSierpinskiSponge" );
-
- if ( num_levels == 0 )
- {
- glBegin ( GL_TRIANGLES ) ;
-
- for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
- {
- glNormal3d ( -tet_r[i][0], -tet_r[i][1], -tet_r[i][2] ) ;
- for ( j = 0; j < 3; j++ )
- {
- double x = offset[0] + scale * tet_r[tet_i[i][j]][0] ;
- double y = offset[1] + scale * tet_r[tet_i[i][j]][1] ;
- double z = offset[2] + scale * tet_r[tet_i[i][j]][2] ;
- glVertex3d ( x, y, z ) ;
- }
- }
-
- glEnd () ;
- }
- else if ( num_levels > 0 )
- {
- GLdouble local_offset[3] ; /* Use a local variable to avoid buildup of roundoff errors */
- num_levels -- ;
- scale /= 2.0 ;
- for ( i = 0 ; i < TETR_NUM_FACES ; i++ )
- {
- local_offset[0] = offset[0] + scale * tet_r[i][0] ;
- local_offset[1] = offset[1] + scale * tet_r[i][1] ;
- local_offset[2] = offset[2] + scale * tet_r[i][2] ;
- glutSolidSierpinskiSponge ( num_levels, local_offset, scale ) ;
- }
- }
-}
-
/* -- INTERFACE FUNCTIONS -------------------------------------------------- */
void FGAPIENTRY glutWireTetrahedron( void )
{
FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutWireTetrahedron" );
-
fghTetrahedron( TRUE );
}
void FGAPIENTRY glutSolidTetrahedron( void )
{
FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidTetrahedron" );
-
fghTetrahedron( FALSE );
}
+void FGAPIENTRY glutWireSierpinskiSponge ( int num_levels, GLdouble offset[3], GLdouble scale )
+{
+ FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutWireSierpinskiSponge" );
+ fghSierpinskiSponge ( num_levels, offset, scale, TRUE );
+}
+void FGAPIENTRY glutSolidSierpinskiSponge ( int num_levels, GLdouble offset[3], GLdouble scale )
+{
+ FREEGLUT_EXIT_IF_NOT_INITIALISED ( "glutSolidSierpinskiSponge" );
+ fghSierpinskiSponge ( num_levels, offset, scale, FALSE );
+}
+
/*** END OF FILE ***/