Function addshadowbox

source/src/shadow.cpp:153–250

}

bool addshadowbox(const vec &bbmin, const vec &bbmax, const vec &extrude, const glmatrixf &mat)
{
    vec4 v[8];
    float sx1 = 1e16f, sy1 = 1e16f, sx2 = -1e16f, sy2 = -1e16f;
    int front = 0;
    loopi(8)
    {
        vec4 &p = v[i];
        mat.transform(vec(i&1 ? bbmax.x : bbmin.x, i&2 ? bbmax.y : bbmin.y, i&4 ? bbmax.z : bbmin.z), p);
        if(p.z >= -p.w)
        {
            float x = p.x / p.w, y = p.y / p.w;
            sx1 = min(sx1, x);
            sy1 = min(sy1, y);
            sx2 = max(sx2, x);
            sy2 = max(sy2, y);
            front++;
        }
    }
    vec4 ev;
    mat.transform(extrude, ev);
    if(ev.z < -ev.w && !front) return false;
    if(front < 8 || ev.z < -ev.w) loopi(8)
    {
        const vec4 &p = v[i];
        if(p.z >= -p.w)
        {
            if(ev.z >= -ev.w) continue;
            float t = ev.z/(ev.z - p.z),
                  w = ev.w + t*(p.w - ev.w),
                  x = (ev.x + t*(p.x - ev.x))/w,
                  y = (ev.y + t*(p.y - ev.y))/w;
            sx1 = min(sx1, x);
            sy1 = min(sy1, y);
            sx2 = max(sx2, x);
            sy2 = max(sy2, y);
            continue;
        }
        loopj(3)
        {
            const vec4 &o = v[i^(1<<j)];
            if(o.z < -o.w) continue;
            float t = p.z/(p.z - o.z),
                  w = p.w + t*(o.w - p.w),
                  x = (p.x + t*(o.x - p.x))/w,
                  y = (p.y + t*(o.y - p.y))/w;
            sx1 = min(sx1, x);
            sy1 = min(sy1, y);
            sx2 = max(sx2, x);
            sy2 = max(sy2, y);
        }
        if(ev.z < -ev.w) continue;
        float t = p.z/(p.z - ev.z),
              w = p.w + t*(ev.w - p.w),
              x = (p.x + t*(ev.x - p.x))/w,
              y = (p.y + t*(ev.y - p.y))/w;
        sx1 = min(sx1, x);
        sy1 = min(sy1, y);