static VtVec3fArray
_GenerateConeMeshPoints(float radius,
float height,
TfToken const & axis)
{
// choose basis vectors aligned with the spine axis
GfVec3f u, v, spine;
if (axis == UsdGeomTokens->x) {
u = GfVec3f::YAxis();
v = GfVec3f::ZAxis();
spine = GfVec3f::XAxis();
} else if (axis == UsdGeomTokens->y) {
u = GfVec3f::ZAxis();
v = GfVec3f::XAxis();
spine = GfVec3f::YAxis();
} else { // (axis == UsdGeomTokens->z)
u = GfVec3f::XAxis();
v = GfVec3f::YAxis();
spine = GfVec3f::ZAxis();
}
// compute a ring of points with unit radius in the uv plane
std::vector<GfVec3f> ring(_slices);
for (int i=0; i<_slices; ++i) {
float a = float(2 * M_PI * i) / _slices;
ring[i] = u * cosf(a) + v * sinf(a);
}
int numPoints = _slices * (_stacks + 1 + 1) + 1;
// populate points
VtVec3fArray pointsArray(numPoints);
GfVec3f * p = pointsArray.data();
// base cap
*p++ = spine * -height/2.0f;
for (int j=0; j<_slices; ++j) {
*p++ = radius * ring[j] + spine * -height/2.0f;
}
// cone
for (int i=0; i<=_stacks; ++i) {
float t = float(i) / _stacks;
float r = radius * (1.0f - t);
float w = height * (t - 0.5f);
for (int j=0; j<_slices; ++j) {
*p++ = r * ring[j] + spine * w;
}
}
TF_VERIFY(p - pointsArray.data() == numPoints);
return pointsArray;
}
static VtVec3fArray
_GenerateCapsuleMeshPoints(float radius, float height, TfToken const & axis)
{
// choose basis vectors aligned with the spine axis
GfVec3f u, v, spine;
if (axis == UsdGeomTokens->x) {
u = GfVec3f::YAxis();
v = GfVec3f::ZAxis();
spine = GfVec3f::XAxis();
} else if (axis == UsdGeomTokens->y) {
u = GfVec3f::ZAxis();
v = GfVec3f::XAxis();
spine = GfVec3f::YAxis();
} else { // (axis == UsdGeomTokens->z)
u = GfVec3f::XAxis();
v = GfVec3f::YAxis();
spine = GfVec3f::ZAxis();
}
// compute a ring of points with unit radius in the uv plane
std::vector<GfVec3f> ring(_slices);
for (int i=0; i<_slices; ++i) {
float a = float(2 * M_PI * i) / _slices;
ring[i] = u * cosf(a) + v * sinf(a);
}
int numPoints = _slices * (_stacks + 1) // cylinder
+ 2 * _slices * (_hemisphereStacks-1) // hemispheres
+ 2; // end points
// populate points
VtVec3fArray pointsArray(numPoints);
GfVec3f * p = pointsArray.data();
// base hemisphere
*p++ = spine * (-height/2-radius);
for (int i=0; i<_hemisphereStacks-1; ++i) {
float a = float(M_PI / 2) * (1.0f - float(i+1) / _hemisphereStacks);
float r = radius * cosf(a);
float w = radius * sinf(a);
for (int j=0; j<_slices; ++j) {
*p++ = r * ring[j] + spine * (-height/2-w);
}
}
// middle
for (int i=0; i<=_stacks; ++i) {
float t = float(i) / _stacks;
float w = height * (t - 0.5f);
for (int j=0; j<_slices; ++j) {
*p++ = radius * ring[j] + spine * w;
}
}
// top hemisphere
for (int i=0; i<_hemisphereStacks-1; ++i) {
float a = float(M_PI / 2) * (float(i+1) / _hemisphereStacks);
float r = radius * cosf(a);
float w = radius * sinf(a);
for (int j=0; j<_slices; ++j) {
*p++ = r * ring[j] + spine * (height/2+w);
}
}
*p++ = spine * (height/2.0f+radius);
TF_VERIFY(p - pointsArray.data() == numPoints);
return pointsArray;
}
