`

//////////// djafer ////////       
 mat4 ajustwMatrix (float theta) {
     return  mat4(
        vec4(cos(theta),  sin(theta),  0.0, 0.0),
        vec4(-sin(theta), cos(theta),  0.0, 0.0),
        vec4(0.0,         0.0,         1.0, 0.0),
        vec4(0.0,         0.0,         0.0, 1.0)
    ); 
 
 }
mat4 rotate_x(float theta)
{
    return mat4(
        vec4(1.0,  0.0,         0.0,        0.0),
        vec4(0.0,  cos(theta),  sin(theta), 0.0),
        vec4(0.0, -sin(theta),  cos(theta), 0.0),
        vec4(0.0,  0.0       ,  0.0       , 1.0)
    );
}

mat4 rotate_y(float theta)
{
    return mat4(
        vec4(cos(theta),  0.0, sin(theta), 0.0),
        vec4(0.0,         1.0, 0.0       , 0.0),
        vec4(-sin(theta), 0.0, cos(theta), 0.0),
        vec4(0.0,         0.0, 0.0,        1.0)
    );
}

mat4 rotate_z(float theta)
{
    return mat4(
        vec4(cos(theta),  sin(theta),  0.0, 0.0),
        vec4(-sin(theta), cos(theta),  0.0, 0.0),
        vec4(0.0,         0.0,         1.0, 0.0),
        vec4(0.0,         0.0,         0.0, 1.0)
    );
}

    //uniforms
    uniform mat4 uNormalMatrix;
    uniform mat4 uModelViewMatrix;
    uniform mat4 uProjectionMatrix;
    
    //ambient lights
//    uniform vec3 uAmbientColor;
    uniform vec3 uAmbientLightingColor;

    
    //directional lights
    uniform vec3 uLightingDirection;
    uniform vec3 uDirectionalLightingColor ;  //uDirectionalColor;
    
///// point lights
    uniform vec3 uPointLightingLocation;
    uniform vec3 uPointLightingColor;

//switch lights on/off
    uniform bool uUseLighting;
    

/////
    
    //attribute
//    attribute vec4 aVertexPosition;
     attribute vec3 aVertexPosition;
   attribute vec3 aVertexNormal;
    attribute vec2 aTextureCoord;
    attribute vec3 aVertexColor ;     
    //varying
    //varying vec2 vTextureCoord;
    varying highp vec2 vTextureCoord;
    varying highp vec3 vLighting;
    varying highp vec3 vLightWeighting;
    varying highp vec4 vColor;

//    varying vec3 vTransformedNormal; // ?
    varying vec4 vTransformedNormal; // ?
    varying vec4 vPosition;  // ?



////////// end /////////////
    void main(void) {
       vec4 mvPosition = uModelViewMatrix * vec4(aVertexPosition, 1.0);
//        gl_Position = uProjectionMatrix * mvPosition;
        vPosition = uModelViewMatrix * vec4(aVertexPosition, 1.0);
        gl_Position = uProjectionMatrix * uModelViewMatrix * vec4(aVertexPosition, 1.0);


      // Apply textures and colors
      vTextureCoord = aTextureCoord;
        vColor = vec4(aVertexColor, 1.0);
      
      // Apply lighting effect

//        vTransformedNormal = uNormalMatrix * aVertexNormal;
        vTransformedNormal  = uNormalMatrix * vec4(aVertexNormal, 1.0);
        if (!uUseLighting) {
     //       vLightWeighting = vec3(0.5, 0.0, 0.0);
        } else {

        
        //directional lights

     highp vec4 directionalTransformedNormal = uNormalMatrix * vec4(aVertexNormal, 1.0);
     float directionDirectionalLightWeighting = max(dot(directionalTransformedNormal.xyz, uLightingDirection), 0.0);
     highp vec3  directionalLightWeighting =   uDirectionalLightingColor * directionDirectionalLightWeighting;


    
        /// point lights
            highp vec3 pointLightDirection = normalize(uPointLightingLocation - mvPosition.xyz);
            highp vec4 pointTransformedNormal = uNormalMatrix * vec4(aVertexNormal, 1.0);
            float directionPointLightWeighting = max(dot(pointTransformedNormal.xyz, pointLightDirection), 0.0);
           highp vec3   pointLightWeighting =  uPointLightingColor * directionPointLightWeighting;
            
            
             vLightWeighting = uAmbientLightingColor + pointLightWeighting + directionalLightWeighting ;

        }   

}`