第 1 课：Shadowmap - view

实现

attribute vec4 color;

varying vec3 vLightDir;
varying vec3 vNormal;
varying vec4 vColor;

void main() {
  vec3 lightDir = normalize(vec3(-0.5, -0.8, 0.0));
  vec3 lightPos = vec3(1.5, 2.4, 0.0);
  vec3 vectorWorldUp = vec3(0.0, 1.0, 0.0);
  vec3 vectorRight = normalize(cross(vectorWorldUp, -lightDir));
  vec3 vectorUp = normalize(cross(-lightDir, vectorRight));

  mat4 viewMatrix = transpose(mat4(
  vec4(vectorRight, 0.0),
  vec4(vectorUp, 0.0),
  vec4(-lightDir, 0.0),
  vec4(vec3(0.0), 1.0)
  ));

  mat4 TranslationMatrix = transpose(mat4(
  vec4(1.0, 0.0, 0.0, -lightPos.x),
  vec4(0.0, 1.0, 0.0, -lightPos.y),
  vec4(0.0, 0.0, 1.0, -lightPos.z),
  vec4(vec3(0.0), 1.0)
  ));


  mat4 lightView = viewMatrix * TranslationMatrix;

  gl_Position = projectionMatrix * lightView * modelMatrix * vec4(position, 1.0);

  vLightDir = lightDir;
  vNormal = mat3(modelMatrix) * normal;
  vColor = color;
}