void color::blend(const color &other) {
if (other.is_invisible()) return;
r = alpha_over_c(other.r, other.a, r, a);
g = alpha_over_c(other.g, other.a, g, a);
b = alpha_over_c(other.b, other.a, b, a);
a = a + (other.a * (0xff - a)) / 0xff;
r = ((r * 0xff) / a);
g = ((g * 0xff) / a);
b = ((b * 0xff) / a);
}
void image_operations::add_pixel(pos_t x, pos_t y, color &c)
{
if (c.is_invisible()) {
return;
}
if (!(x >= min_x)) { return; }
if (!(y >= min_y)) { return; }
if (!(x < max_x)) { return; }
if (!(y < max_y)) { return; }
color n = color(c);
// tag with depth.
n.z = z;
image_operation oper;
oper.x = (uint16_t)x;
oper.y = (uint16_t)y;
oper.c = n;
operations.push_back(oper);
}