Opengl Es 更新动画中每个顶点的法线

Question

下面的代码 (original is here) 不更新法线，我怎样才能更新法线？

假设userData有normals属性，vertex shader做了相关修改。并将第 76 行中的第一个 NULL 更改为 &userData->normals 等

///
// Update MVP matrix based on time
//
void Update ( ESContext *esContext, float deltaTime )
{
   UserData *userData = (UserData*) esContext->userData;
   ESMatrix perspective;
   ESMatrix modelview;
   float    aspect;

   // Compute a rotation angle based on time to rotate the cube
   userData->angle += ( deltaTime * 40.0f );
   if( userData->angle >= 360.0f )
      userData->angle -= 360.0f;

   // Compute the window aspect ratio
   aspect = (GLfloat) esContext->width / (GLfloat) esContext->height;

   // Generate a perspective matrix with a 60 degree FOV
   esMatrixLoadIdentity( &perspective );
   esPerspective( &perspective, 60.0f, aspect, 1.0f, 20.0f );

   // Generate a model view matrix to rotate/translate the cube
   esMatrixLoadIdentity( &modelview );

   // Translate away from the viewer
   esTranslate( &modelview, 0.0, 0.0, -2.0 );

   // Rotate the cube
   esRotate( &modelview, userData->angle, 1.0, 0.0, 1.0 );

   // Compute the final MVP by multiplying the 
   // modevleiw and perspective matrices together
   esMatrixMultiply( &userData->mvpMatrix, &modelview, &perspective );
}

Answer 1

法线变换矩阵是模型视图矩阵的逆转置。所以你必须计算它并提供额外的制服来转换法线。

Opengl Es 更新动画中每个顶点的法线

Opengl Es update normals for each vertex in an animation

opengl

3d

opengl-es

matrix