Bush, Alex W. wrote:
> What exactly is wrong with the cylinders? Without seeing a short code sketch
> or at least a picture it's hard to tell what is wrong with your method.
>
> If I had to guess, I'd probably take a look at the order of your
> transformations. Make sure your displacement of the second cylinder is
> happening before the transformation (if you reverse these you will get two
> parallel cylinders positioned on top of each other vertically).
>
> Alex
>
Thanks for the response! I will provide a short sketch of a function which is
recursively called for each cylinder rendered. I am also attaching a picture of
what this function renders when recursively called four times. Thank you very
much.
Code:
void Stem::make_stem_segments(float stem_len, int num_segments, int seg_index,
float base_radius, float head_radius, osg::Vec3 top_of_prev_unrotated_cylinder,
osg::Vec3 top_of_prev_rotated_cylinder, float rotate_degrees_second_half, float
rotate_degrees_first_half, float random_degrees_rotation, int left) {
if (num_segments == 0)
return;
float rotation_amount;
float seg_length = stem_len / this->num_segments;
// Determine whether segment is in first or second half of stem.
if (seg_index >= (this->num_segments / 2)) {
rotation_amount = rotate_degrees_second_half +
random_degrees_rotation;
} else {
rotation_amount = rotate_degrees_first_half +
random_degrees_rotation;
}
// Render vertical cylinder
osg::Geode* stem_geode = new osg::Geode();
osg::PositionAttitudeTransform* stem_transform =
new osg::PositionAttitudeTransform();
stem_transform->addChild(stem_geode);
osg::Cylinder * cylinder = new osg::Cylinder(osg::Vec3(0.0, 0.0,
seg_length / 2), base_radius, seg_length);
osg::ShapeDrawable* cylinder_drawable = new
osg::ShapeDrawable(cylinder);
stem_geode->addDrawable(cylinder_drawable);
// Position new cylinder.
stem_transform->setPosition(osg::Vec3(top_of_prev_unrotated_cylinder.x(),
top_of_prev_unrotated_cylinder.y(), top_of_prev_unrotated_cylinder.z()));
osg::Vec3 top_of_new_unrotated_cylinder =
osg::Vec3(top_of_prev_unrotated_cylinder.x(),
top_of_prev_unrotated_cylinder.y(), top_of_prev_unrotated_cylinder.z() +
seg_length);
// Rotate cylinder.
osg::Quat rot_quat = osg::Quat(osg::DegreesToRadians(0.0f),
osg::Vec3d(0, 0,
1)))*(osg::Quat(osg::DegreesToRadians(rotation_amount),
osg::Vec3d(1, 0, 0)))*(osg::Quat(osg::DegreesToRadians(0.0),
osg::Vec3d(0, 1, 0));
stem_transform->setAttitude(rot_quat);
const osg::Matrixd &rot_mat = osg::Matrixd(rot_quat);
top_of_prev_rotated_cylinder = rot_mat * top_of_new_unrotated_cylinder;
osg::Matrixd inverse;
if (!inverse.invert(rot_mat))
std::cout << "COULD NOT COMPUTE INVERSE" << std::endl;
top_of_prev_unrotated_cylinder = inverse * top_of_prev_rotated_cylinder;
this->stem->addChild(stem_transform);
// Recursively make another stem segment
make_stem_segments(stem_len, num_segments - 1, seg_index + 1,
base_radius, head_radius, top_of_prev_unrotated_cylinder,
top_of_prev_rotated_cylinder, rotate_degrees_second_half,
rotate_degrees_first_half, random_degrees_rotation, 1);
}
[/code]
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=59591#59591
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