martinchristen/pyRT

"""
Phong Material

For phong shading
"""
from .material import Material
from ..math import Vec3, Ray, HitRecord, dot3, reflect3, normalize3, clamp3
from ..camera import Camera


class PhongMaterial(Material):

    """Base Material Class"""

    def __init__(self, color: Vec3 = Vec3(1.,1.,1.), shininess: float = 10.0, reflectivity: float = 0.0, refraction: float = 1.0, transparency = 0.0):
        Material.__init__(self, color, shininess, reflectivity, refraction, transparency)

    def shade(self, camera: Camera, ray: Ray, hitrecord: HitRecord,  lights: list) -> Vec3:
        """
        Shade method: Phong

        phong shader
        """
        colorsum = Vec3(0.,0.,0.)

        if len(lights)>0:
            for light in lights:
                N = normalize3(hitrecord.normal_g)
                L = normalize3(hitrecord.point - light.position)
                E = normalize3(camera.position - hitrecord.point)
                R = normalize3(-reflect3(L, N))
                diffuse = max(1. - dot3(N, L), 0.0)
                specular = pow(max(dot3(R, E), 0.0), 0.3 * self.shininess)
                color = self.color * 0.5 * (diffuse + specular) * hitrecord.color
                colorsum += color
            colorsum /= len(lights)
            colorsum = clamp3(colorsum, Vec3(0.,0.,0.), Vec3(1.,1.,1.))
        else:
            # no light in scene, use material color
            colorsum = self.color * hitrecord.color

        return colorsum