draw mesh at 0,0,-1000 opengl/webgl

OpenGL OpenGL: Basic Coding
1

hello.
I have this test webgl vertex shader:


<script id="TextureEffectv" type="x-shader/x-vertex">
    attribute vec3 aVertexPosition;
    attribute vec3 aVertexNormal;
    attribute vec2 aTextureCoord;

    uniform mat4 uMVMatrix;
    uniform mat4 uPMatrix;
    uniform mat3 uNMatrix;

    uniform vec3 uAmbientColor;
    uniform vec3 uLightingDirection;
    uniform vec3 uLightingDirection2;
    uniform vec3 CameraModelPosition;
    
    uniform vec3 ColorFront;
    uniform vec3 ColorBack;
    varying vec3 transformedNormal;
    varying vec3 vLightWeighting;
    varying vec3 vLightWeightingback;
    varying vec2 vTextureCoord;
    void main(void) {
        gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
       
        vTextureCoord = aTextureCoord;
        vec3 uDirectionalColor = vec3(1,1,1);    
        transformedNormal = uNMatrix * aVertexNormal;
        
        float directionalLightWeighting = max(dot(transformedNormal, uLightingDirection), 0.0) ;
        vLightWeighting = uDirectionalColor * directionalLightWeighting * ColorFront ;
        
        float directionalLightWeighting2 = max(dot(transformedNormal, uLightingDirection2), 0.0) ;
        vLightWeighting +=  uDirectionalColor * directionalLightWeighting2 * ColorFront ;
        
         float directionalLightWeightingback = max(dot(transformedNormal, uLightingDirection), 0.0) ;
        vLightWeightingback = uDirectionalColor * directionalLightWeightingback * ColorBack ;
        
        float directionalLightWeighting2back = max(dot(transformedNormal, uLightingDirection2), 0.0) ;
        vLightWeightingback +=  uDirectionalColor * directionalLightWeighting2back * ColorBack ;
    }
</script>

Now i would draw a mesh at 0,0,-1000 without the gllookat or glorto.
I have only the uMVMatrix for do this, is sufficent?
how i can change the word view matrix for draw the mesh at 0,0,-1000?
I know that the camera position is the inverse of the word view matrix?
but… i 'm not understand at all
thanks.

2

I’m expalin better:


void Camera::updateViewMatrix()
{
    // Reconstruct the view matrix.

    m_viewMatrix = m_orientation.toMatrix4();

    m_xAxis.set(m_viewMatrix[0][0], m_viewMatrix[1][0], m_viewMatrix[2][0]);
    m_yAxis.set(m_viewMatrix[0][1], m_viewMatrix[1][1], m_viewMatrix[2][1]);
    m_zAxis.set(m_viewMatrix[0][2], m_viewMatrix[1][2], m_viewMatrix[2][2]);
    m_viewDir = -m_zAxis;

    if (m_behavior == CAMERA_BEHAVIOR_ORBIT)
    {
        // Calculate the new camera position based on the current
        // orientation. The camera must always maintain the same
        // distance from the target. Use the current offset vector
        // to determine the correct distance from the target.

        m_eye = m_target + m_zAxis * m_orbitOffsetDistance;
    }

    m_viewMatrix[3][0] = -Vector3::dot(m_xAxis, m_eye);
    m_viewMatrix[3][1] = -Vector3::dot(m_yAxis, m_eye);
    m_viewMatrix[3][2] = -Vector3::dot(m_zAxis, m_eye);
}

i choose the m_behavior == CAMERA_BEHAVIOR_ORBIT use of the camera.
the orientation is the orientation of the camera in quaternion m_orientation.toMatrix4(); .
the camera have a CRender class reference and, this.m_render.UpdateFromCamera(this); calls the CRender class
get the matrixes from the camera(the CRender class have also a reference to camera object)then draw the mesh in the scene with those matrixes.

The problem is this:
I use a shader for drawing the mesh and create an orbit camera system.
the model is always at 0;0;0 or other arbitrary positions, the thing that change is the camera (orientation and position) i can set the orientation and position in the MVMatrix , but if i place those how i can draw the mesh at 0;0;0 ??
How i can draw the mesh at 0;0;0 and apply the Model view matrix that return my camera object and have the eye position and camera orientation?
thanks.