07 Surfaces and light

Highlights: the view joins in

Diffuse only looks at the light; a highlight also depends on where you look from. Turn the sphere and compare.

Shininess (exponent)32

2256

Specular strength0.80

Light direction X-0.60

-22

Runs once per pixelDrag numbers, or edit the code

void main() {
  vec3 N = normalize(vNormal);
  vec3 L = normalize(vec3(-0.600, 0.8, 1.0));
  vec3 V = normalize(uCameraPos - vWorld);   // toward the camera
  vec3 H = normalize(L + V);                 // halfway between light and view
  float diffuse = max(dot(N, L), 0.0);
  float spec = pow(max(dot(N, H), 0.0), 32.000) * step(0.0, dot(N, L));
  vec3 color = vec3(0.96, 0.43, 0.30) * (0.1 + 0.9 * diffuse) + vec3(0.800 * spec);
  gl_FragColor = vec4(color, 1.0);
}

void main() {
  vec3 N = normalize(vNormal);
  vec3 L = normalize(vec3(-0.600, 0.8, 1.0));
  vec3 V = normalize(uCameraPos - vWorld);   // toward the camera
  vec3 H = normalize(L + V);                 // halfway between light and view
  float diffuse = max(dot(N, L), 0.0);
  float spec = pow(max(dot(N, H), 0.0), 32.000) * step(0.0, dot(N, L));
  vec3 color = vec3(0.96, 0.43, 0.30) * (0.1 + 0.9 * diffuse) + vec3(0.800 * spec);
  gl_FragColor = vec4(color, 1.0);
}

JS sidegl.uniformMatrix4fv(uModel, …) // rotation -0.35 / 0.10

Highlights depend on the view: H is halfway between light and view, and the closer N is to H the brighter; a larger exponent makes a smaller, sharper spot.

Try it

Raise shininess from 8 to 128
Turn the sphere: does the highlight move?