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mesh_generators.cpp
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mesh_generators.cpp
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/* Some example mesh functions */
#include "mesh_generators.hpp"
TriangleMesh GenerateParametricSphereMesh(const int &rings, const int &slices)
{
vector<MeshTriangle> tlist; // contains triangles for mesh
vector<MeshVertex> vlist; // contains vertices for mesh
// parametric eq for a point on a sphere given u = theta, v = phi
auto sphere_pt = [](float u, float v) {
return vec3(
sin(u)*cos(v),
cos(u),
-sin(u)*sin(v));
};
GeneratePoints(vlist, rings, slices, sphere_pt, 2.0f*pi/(float)rings, pi/(float)slices);
GenerateFaces(tlist, rings, slices);
GenerateSphereVertexNormals(vlist);
TriangleMesh sphere;
sphere.nv = vlist.size();
sphere.nt = tlist.size();
sphere.vertexArray = (MeshVertex*) malloc(vlist.size() * sizeof(MeshVertex));
sphere.triangleArray = (MeshTriangle*) malloc(tlist.size() * sizeof(MeshTriangle));
copy(vlist.begin(), vlist.begin() + vlist.size(), sphere.vertexArray);
copy(tlist.begin(), tlist.begin() + tlist.size(), sphere.triangleArray);
return sphere;
}
TriangleMesh GenerateParametricKleinMesh(const int &rings, const int &slices)
{
vector<MeshTriangle> tlist; // contains triangles for mesh
vector<MeshVertex> vlist; // contains vertices for mesh
// Equation for a point on a Klein bottle given u = theta, v = phi
auto klein_pt = [](float u, float v) {
float x, y, z;
if (u < pi) {
x = 3.0f*cos(u)*(1.0f+sin(u))+(2.0f*(1.0f-cos(u)/2.0f))*cos(u)*cos(v);
z = -8.0f*sin(u)-2.0f*(1.0f-cos(u)/2.0f)*sin(u)*cos(v);
}
else {
x = 3.0f*cos(u)*(1.0f+sin(u))+(2.0f*(1.0f-cos(u)/2.0f))*cos(v+pi);
z = -8.0f*sin(u);
}
y = -2.0f*(1.0f-cos(u)/2.0f)*sin(v);
return vec3(x,y,z);
};
GeneratePoints(vlist, rings, slices, klein_pt, 2.0f*pi/(float)rings, 2.0f*pi/(float)slices);
GenerateFaces(tlist, rings, slices);
GenerateVertexNormals(vlist, tlist);
TriangleMesh klein;
klein.nv = vlist.size();
klein.nt = tlist.size();
klein.vertexArray = (MeshVertex*) malloc(vlist.size() * sizeof(MeshVertex));
klein.triangleArray = (MeshTriangle*) malloc(tlist.size() * sizeof(MeshTriangle));
copy(vlist.begin(), vlist.begin() + vlist.size(), klein.vertexArray);
copy(tlist.begin(), tlist.begin() + tlist.size(), klein.triangleArray);
return klein;
}
TriangleMesh GenerateParametricTorusMesh(const int &rings, const int &slices)
{
vector<MeshTriangle> tlist; // contains triangles for mesh
vector<MeshVertex> vlist; // contains vertices for mesh
auto torus_pt = [](float u, float v) {
float x, y, z;
x = (1 + 0.5*cos(u)) * cos(v);
y = (1 + 0.5*cos(u)) * sin(v);
z = 0.5 * sin(u);
return vec3(x,y,z);
};
GeneratePoints(vlist, rings, slices, torus_pt, 2.0f*pi/(float)rings, 2.0f*pi/(float)rings);
GenerateFaces(tlist, rings, slices);
GenerateVertexNormals(vlist, tlist);
TriangleMesh torus;
torus.nv = vlist.size();
torus.nt = tlist.size();
torus.vertexArray = (MeshVertex*) malloc(vlist.size() * sizeof(MeshVertex));
torus.triangleArray = (MeshTriangle*) malloc(tlist.size() * sizeof(MeshTriangle));
copy(vlist.begin(), vlist.begin() + vlist.size(), torus.vertexArray);
copy(tlist.begin(), tlist.begin() + tlist.size(), torus.triangleArray);
return torus;
}
TriangleMesh GenerateBagelKleinMesh(const int &rings, const int &slices)
{
vector<MeshTriangle> tlist; // contains triangles for mesh
vector<MeshVertex> vlist; // contains vertices for mesh
auto klein_pt = [](float u, float v) {
float x, y, z;
x = (1.0f + cos(v/2.0f)*sin(u) - sin(v/2.0f)*sin(2.0f*u)) * cos(v);
y = (1 + cos(v/2.0f)*sin(u) - sin(v/2.0f)*sin(2.0f*u)) * sin(v);
z = sin(v/2.0f)*sin(u) + cos(v/2.0f)*sin(2.0f*u);
return vec3(x,y,z);
};
GeneratePoints(vlist, rings, slices, klein_pt, 2.0f*pi/(float)rings, 2.0f*pi/(float)rings);
GenerateFaces(tlist, rings, slices);
GenerateVertexNormals(vlist, tlist);
TriangleMesh klein;
klein.nv = vlist.size();
klein.nt = tlist.size();
klein.vertexArray = (MeshVertex*) malloc(vlist.size() * sizeof(MeshVertex));
klein.triangleArray = (MeshTriangle*) malloc(tlist.size() * sizeof(MeshTriangle));
copy(vlist.begin(), vlist.begin() + vlist.size(), klein.vertexArray);
copy(tlist.begin(), tlist.begin() + tlist.size(), klein.triangleArray);
return klein;
}