顶点和片段着色器中旋转矩阵的差异结果

Question

I have a problem with rotation matrix.It gives different results in Vertex and fragment shaders.

There are two objects. First is sphere.Sphere needs its texture to be rotated in the fragment shader. It works fine and matches the GUI algorithm. Used exact same algorithm.

Second object is points (sprites). It should rotated around sphere by same angles.

I use next algorithm in fragment and vertex shader:

mat3 rotateX = mat3(
   1.0, 0, 0,
   0, cos(angles.x), -sin(angles.x),
   0, sin(angles.x), cos(angles.x)
   );

   mat3 rotateY = mat3(
   cos(angles.y), 0, sin(angles.y),
   0, 1, 0,
   -sin(angles.y), 0, cos(angles.y)
   );

   mat3 rotateZ = mat3(
   cos(angles.z), -sin(angles.z), 0,
   sin(angles.z), cos(angles.z), 0,
   0, 0, 1
   );

   float Fi = (-current.x) * M_PI;
   float Te = current.y * M_PI;

   vec3 coord;
   coord.x = sin(Te) * cos(Fi);
   coord.y = sin(Te) * sin(Fi);
   coord.z = cos(Te);

   coord = vec3(coord.x, coord.y, coord.z) * rotateX * rotateY * rotateZ;

I have the following problem. If making rotation from one any Axis, all is ok. If making rotation by two or three Axis then sphere and points rotate in difference directions.

Its normal behavior (start position and one axis rotation): http://joxi.ru/JqkaVP3JTJA_Xelvbds

Its after begining rotation: http://joxi.ru/qqoaVIwyTJBWeTcvy4A

What am I doing wrong?

Using WebGL (OpenGL ES2).

Answer 1

I solved the problem. Just need to multiply rotation matrix in reverse order.

Shader for fragment rotation

   mat3 rotateX = mat3(
   1.0, 0, 0,
   0, cos(angles.x), -sin(angles.x),
   0, sin(angles.x), cos(angles.x)
   );

   mat3 rotateY = mat3(
   cos(angles.y), 0, sin(angles.y),
   0, 1, 0,
   -sin(angles.y), 0, cos(angles.y)
   );

   mat3 rotateZ = mat3(
   cos(angles.z), -sin(angles.z), 0,
   sin(angles.z), cos(angles.z), 0,
   0, 0, 1
   );

   float Fi = (-cUv.x + 0.25) * 2.0 * M_PI;
   float Te = cUv.y * M_PI;  

   vec3 coord;
   coord.x = sin(Te) * cos(Fi);
   coord.y = sin(Te) * sin(Fi);
   coord.z = cos(Te);

   coord = coord * rotateX * rotateY * rotateZ;

Shader for vertex rotation

angles = -angles;

mat3 rotateX = mat3(
    1.0, 0, 0,
    0, cos(angles.x), -sin(angles.x),
    0, sin(angles.x), cos(angles.x)
);

mat3 rotateY = mat3(
    cos(angles.y), 0, sin(angles.y),
    0, 1, 0,
    -sin(angles.y), 0, cos(angles.y)
);

mat3 rotateZ = mat3(
    cos(angles.z), -sin(angles.z), 0,
    sin(angles.z), cos(angles.z), 0,
    0, 0, 1
);

float Fi = (-curPosition.x) * M_PI; //hor
float Te = (curPosition.y) * M_PI; //vert

vec3 coord;
coord.x = sin(Te) * cos(Fi);
coord.y = sin(Te) * sin(Fi);
coord.z = cos(Te);

return coord * rotateZ * rotateY * rotateX;