create capsule mesh on Houdini VEX

create_capsule_mesh

#include "math.h"

// parameters
float hsheight1 = ch("../hsheightx");
float hsheight2 = ch("../hsheighty");
vector size = chv("../size");
int hsrows1 = chi("../hsrowsx");
int hsrows2 = chi("../hsrowsy");
int tubesplitnum = chi("../tubesplitnum");
int cols = chi("../cols");

// constant values
float radx = size.x * 0.5;
float radz = size.z * 0.5;
float sizey_half = size.y * 0.5;

// ===================
// create points
// ===================

// polar points
addpoint(0, set(0,  sizey_half + hsheight1, 0));
addpoint(0, set(0, -sizey_half - hsheight2, 0));

// upper hemisphere
for (int row = 0; row < hsrows1; row++)
{
    float rt = M_PI * 0.5 * ((float)(row+1) / hsrows1);
    float cy = cos(rt);
    float sy = sin(rt);
    for (int col = 0; col < cols; col++)
    {
        float ct = M_PI * 2.0 * ((float)col / cols);
        vector pos = {0, 0, 0};
        pos.x = radx * cos(ct) * sy;
        pos.y = hsheight1 * cy + sizey_half;
        pos.z = radz * -sin(ct) * sy;
        addpoint(0, pos);
    }
}

// tube
float tube_row_height = size.y / (tubesplitnum+1);
for (int row = 0; row < tubesplitnum; row++)
{
    float rt = tube_row_height * (row + 1);
    float cy = sizey_half - rt;
    for (int col = 0; col < cols; col++)
    {
        float ct = M_PI * 2.0 * ((float)col / cols);
        vector pos = {0, 0, 0};
        pos.x = radx * cos(ct);
        pos.y = cy;
        pos.z = radz * -sin(ct);
        addpoint(0, pos);
    }
}

// lower hemisphere
for (int row = 0; row < hsrows2; row++)
{
    float rt = M_PI * 0.5 * (1 - ((float)row / hsrows2));
    float cy = cos(rt);
    float sy = sin(rt);
    for (int col = 0; col < cols; col++)
    {
        float ct = M_PI * 2.0 * ((float)col / cols);
        vector pos = {0, 0, 0};
        pos.x = radx * cos(ct) * sy;
        pos.y = -hsheight2 * cy - sizey_half;
        pos.z = radz * -sin(ct) * sy;
        addpoint(0, pos);
    }
}

// =======================
// create primitives
// =======================

// upper polar triangles
for (int col = 0; col < cols; col++)
{
    int p1 = 0;
    int p2 = 2 + ((col + 1) % cols);
    int p3 = 2 + col;
    addprim(0, "poly", p1, p2, p3);
}

// quads
int primrows = hsrows1 + hsrows2 + tubesplitnum - 1;
for (int row = 0; row < primrows; row++)
{
    for (int col = 0; col < cols; col++)
    {
        int ofs = row * cols;
        int p1 = 2 + col + ofs;
        int p2 = 2 + ((col + 1) % cols) + ofs;
        int p3 = p2 + cols;
        int p4 = p1 + cols;
        addprim(0, "poly", p1, p2, p3, p4);
    }
}

// lower polar triangles
int ofs = primrows * cols;
for (int col = 0; col < cols; col++)
{
    int p1 = 1;
    int p2 = 2 + col + ofs;
    int p3 = 2 + ((col + 1) % cols) + ofs;
    addprim(0, "poly", p1, p2, p3);
}