diff options
Diffstat (limited to 'polyset.cc')
| -rw-r--r-- | polyset.cc | 15 |
1 files changed, 15 insertions, 0 deletions
@@ -41,6 +41,18 @@ void PolySet::insert_vertex(double x, double y, double z) polygons.last().insert(0, Point(x, y, z)); } +static void set_opengl_normal(double x1, double y1, double z1, double x2, double y2, double z2, double x3, double y3, double z3) +{ + double ax = x1 - x2, ay = y1 - y2, az = z1 - z2; + double bx = x3 - x2, by = y3 - y2, bz = z3 - z2; + double nx = ay*bz - az*by; + double ny = az*bx - ax*bz; + double nz = ax*by - ay*bx; + double n_scale = 1.0 / sqrt(nx*nx + ny*ny + nz*nz); + nx /= n_scale; ny /= n_scale; nz /= n_scale; + glNormal3d(-nx, -ny, -nz); +} + void PolySet::render_surface(colormode_e colormode) const { if (colormode == COLOR_MATERIAL) @@ -50,6 +62,9 @@ void PolySet::render_surface(colormode_e colormode) const for (int i = 0; i < polygons.size(); i++) { const Polygon *poly = &polygons[i]; glBegin(GL_POLYGON); + set_opengl_normal(poly->at(0).x, poly->at(0).y, poly->at(0).z, + poly->at(1).x, poly->at(1).y, poly->at(1).z, + poly->at(2).x, poly->at(2).y, poly->at(2).z); for (int j = 0; j < poly->size(); j++) { const Point *p = &poly->at(j); glVertex3d(p->x, p->y, p->z); |