shapes: Crash when creating shapes with many removed vertices

[phed]

Example:
shape = par_shapes_create_torus(40, 40, 0.8);

While the crash itself happens deep inside the code (a triangle with a uninitialized value) the problem is caused around par_shapes.h#L1678 :

    for (int p = 0; p < mesh->npoints; p++, src += 3) {
        if (weldmap[p] == p) {
            *dst++ = src[0];
            *dst++ = src[1];
            *dst++ = src[2];
            *cmap++ = ci++;
        } else {
            // NOTE(phed) 
            // Example: p == 556, weldmap[p] == 563
            // condensed_map[weldmap[p]] == uninitialized
            // assert(weldmap[p] < p); // Seems to reliably detect when the error is about to happen
            *cmap++ = condensed_map[weldmap[p]];
        }

A non-fix, but code that seemingly works, I am not sure how to do it in a single pass, so I resorted to a magic number to work around it:

    for (int p = 0; p < mesh->npoints; p++, src += 3) {
        if (weldmap[p] == p) {
            *dst++ = src[0];
            *dst++ = src[1];
            *dst++ = src[2];
            *cmap++ = ci++;
        } else {
            *cmap++ = 65535;
        }
    }
    cmap = condensed_map;
    for (int p = 0; p < mesh->npoints; p++) {
        if (*cmap == 65535) {
            *cmap = condensed_map[weldmap[p]];
        }
        cmap++;
    }

[sonoro1234]

@phed I am not getting a crash for par_shapes_create_torus(40, 40, 0.8);
perhaps you compiled with ffast-math?

[prideout]

Unable to repro. A more correct assert would be:

assert(weldmap[p] < mesh->npoints)