第 1 课：Ins and outs

实现

uniform mat4 modelMatrix;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;

in vec3 position;
in vec3 normal;
in vec4 color;

out vec3 vNormal;
out vec4 vColor;

void main() {
  vColor = color;
  vNormal = mat3(transpose(inverse(modelMatrix))) * normal;
  gl_Position = projectionMatrix * viewMatrix * modelMatrix * vec4(position, 1.0);
}