// calculates the color for the current pixel
//************************************
// Method: calcPixelColor
// FullName: calcPixelColor
// Access: public
// Returns: vec3
// Qualifier:
// Parameter: const ray & r
// Parameter: hitable * world
// Parameter: int depth
// Parameter: shadingmodel shading
//************************************
vec3 calcPixelColor(const ray& r, hitable* world, int depth, shadingmodel shading)
{
hit_record rec;
// shade hit color
if (world->hit(r, 0.001f, FLT_MAX, rec))
{
switch(shading)
{
case normals:
{ return 0.5f * vec3(rec.normal.x + 1.f, rec.normal.y + 1.f, rec.normal.z + 1.f);
break;
}
case shaded:
{ ray scattered;
vec3 attenuation;
if (depth < 50 && rec.mtlPtr->scatter(r, rec, attenuation, scattered))
{
return attenuation * calcPixelColor(scattered, world, depth + 1, shaded);
}
else
return vec3(0.f, 0.f, 0.f);
}
default: { return 0.5f * vec3(rec.normal.x + 1.f, rec.normal.y + 1.f, rec.normal.z + 1.f);
break;
}
}
}
// shade background color
else
{
// normalize (i.e. make unit vector) ray direction, -1.0 < (B.x, B.y, B.z) < 1.0
vec3 unitDirection = r.Direction();
unitDirection.Normalize();
// calculate ray parameter, t, scaled to 0.0 < t < 1.0
float t = 0.5f * (unitDirection.y + 1.f);
// calculate color of pixel at parameter t, where
// @t == 0.0 :: color == white
// @t == 1.0 :: color == blue
// i.e. a LERP between white and blue
// LERP'ed color = (1-t) * startValue + t * EndValue
// ---> LERP'ed color = (1-t) * <white> + t * <blue>
return (1.f - t) * vec3(1.f, 1.f, 1.f) + t * vec3(0.5f, 0.7f, 1.f);
}
}
