On Jun 16, 2004, at 4:51 AM, andreas.poegl wrote:

thanx for answering.. my problem is that i want to create chladni-figures resulting from an analysis within pd the chladni code uses forms like 'for' and i don't know how to implement in gem. ist there are kind of GEMfor ? here is thwe oGL code

Since you already have the C code then it only makes sense to write an external. this will be far faster to write and also run a whole lot better as well. Implementing the following using wrapper objects is going to be nothing but frustration. I have no idea how you would do Paul Bourke's Eval and CalcNormals in a sane manner either.

There is a good chance the next release of GEM might have an object or two based on a few of Bourke's ideas.

cgc

du = TWOPI / (double)resolution; /* Theta */    dv = PI / (double)resolution;    /* Phi   */

glBegin(GL_QUADS);    for (i=0;i<resolution;i++) {       u = i * du;       for (j=0;j<resolution;j++) {          v = j * dv;          q[0] = Eval(u,v);          n[0] = CalcNormal(q[0],                            Eval(u+du/10,v),                            Eval(u,v+dv/10));          c[0] = GetColour(u,0.0,TWOPI,colourmap);          glNormal3f(n[0].x,n[0].y,n[0].z);          glColor3f(c[0].r,c[0].g,c[0].b);          glVertex3f(q[0].x,q[0].y,q[0].z);

q[1] = Eval(u+du,v);          n[1] = CalcNormal(q[1],                            Eval(u+du+du/10,v),                            Eval(u+du,v+dv/10));          c[1] = GetColour(u+du,0.0,TWOPI,colourmap);          glNormal3f(n[1].x,n[1].y,n[1].z);          glColor3f(c[1].r,c[1].g,c[1].b);          glVertex3f(q[1].x,q[1].y,q[1].z);

q[2] = Eval(u+du,v+dv);          n[2] = CalcNormal(q[2],                            Eval(u+du+du/10,v+dv),                            Eval(u+du,v+dv+dv/10));          c[2] = GetColour(u+du,0.0,TWOPI,colourmap);          glNormal3f(n[2].x,n[2].y,n[2].z);          glColor3f(c[2].r,c[2].g,c[2].b);          glVertex3f(q[2].x,q[2].y,q[2].z);

q[3] = Eval(u,v+dv);          n[3] = CalcNormal(q[3],                            Eval(u+du/10,v+dv),                            Eval(u,v+dv+dv/10));          c[3] = GetColour(u,0.0,TWOPI,colourmap);          glNormal3f(n[3].x,n[3].y,n[3].z);          glColor3f(c[3].r,c[3].g,c[3].b);          glVertex3f(q[3].x,q[3].y,q[3].z);       }    }    glEnd();

regards andreas