void
MMLmsqrt::doPaint(MML::Attributes *a) const {
MMLNode *sqrt = first;
v_unit linethickness(0.05, l_unit::em);
float lineth = linethickness.get(a);
sqrt->paint(a);
float ly = -sqrt->getAscent() - 3.5*lineth;
float d = (gui->ascent + gui->descent)/12;
float bx = sqrt->getX();
v_unit ex = v_unit(-0.5, v_unit::ex);
float hex = ex.get(a);
float x[10], y[10];
float px[5], py[5];
float t[4];
px[0] = 0; py[0] = 0.7*hex;
px[1] = d; py[1] = hex;
px[2] = 3*d; py[2] = gui->descent/2;
px[3] = bx; py[3] = ly;
px[4] = gui->width; py[4] = ly;
t[0] = lineth/2;
t[1] = 2*lineth;
t[2] = t[3] = lineth;
rootPoints(px, py, t, x, y);
a->p->drawPolygon(10, x, y);
}
/* Compute the reflection of a vector on an object.
*
* the_object: The object to reflect off of.
* position: The position hit.
* direction: The direction of the vector to be reflected.
*
* Returns: the reflection of direction on the object at position.
*/
float* reflection_vector(object *the_object, float *position, float *direction) {
float *reflection = (float*)malloc(sizeof(float)*3);
float *normal = get_normal(the_object, position);
v_scale(normal, -2*v_dot(direction, normal), reflection);
v_add(reflection, direction, reflection);
v_unit(reflection, reflection);
return reflection;
}
/* Get the normal of a shape at a given position.
*
* the_object: The object to get the normal of.
* position: The position on the object to calculate the normal.
*
* Returns: The normal to the object at the given position.
*/
float* get_normal(object *the_object, float *position) {
float *normal;
if (the_object->type == PLANE_TYPE) normal = the_object->definition.plane.normal;
else {
normal = (float*)malloc(sizeof(float)*3);
v_sub(position, the_object->definition.sphere.center, normal);
v_unit(normal, normal);
}
return normal;
}
