第 8 课：Specular Map

实现

uniform float iTime;
uniform sampler2D iChannel0;
uniform sampler2D iChannel1;

varying vec3 vPos;
varying vec3 vNormal;
varying vec2 vUv;

void main() {
  vec3 viewPos = vec3(0.0, 0.0, 2.5);

  vec3 objectColor = texture2D(iChannel0, vUv).rgb;
  vec3 SpecularMap = texture2D(iChannel1, vUv).rgb;
  vec3 fragNormal = normalize(vNormal);
  vec3 fragPos = vPos;

  vec3 lightColor = vec3(1.0, 1.0, 0.75);
  vec3 lightPos = vec3(-1.0, 2.0, 2.0);
  vec3 lightDir = normalize(lightPos - fragPos);

  float ambient = 0.2;
  float diffuse = max(dot(fragNormal, lightDir), 0.0);

  vec3 viewDir = normalize(viewPos - fragPos);
  vec3 reflectDir = reflect(-lightDir, fragNormal);
  float specular = pow(max(dot(viewDir, reflectDir), 0.0), 8.0);

  vec3 result = lightColor * (objectColor*(ambient + diffuse) + SpecularMap * specular);

  gl_FragColor = vec4(result, 1.0);
}