Enlarge OpenGL ES 2.0 - the object disappears

Question

I like to know how to scale correctly OpenGL ES 2.0. I have successfully drawn a model, but it is quite small, and I can not enlarge this model. What I like is to scale through this model.

The model is a building with different floors - I would like to zoom in to each room on each floor. But either the object disappears due to the truncation representation, or I cannot get very “close” to this object.

I use the zoom-touch gesture and get the value "scale" - what should I do with this value now?

What I have tried so far:

Changing the distance between planes and far planes and changing the value of eyeZ in Matrix.setLookAtM (....), but what I only achieve is scaling ... It disappears when scaling after a bit ... Therefore, I cannot increase some special parts ("thats far" ....)

---

How can i achieve this?

Thus, the biggest problem is getting closer to the plane in combination with scaling through eyeZ-Value. It just doesn't work. If I zoom in, the object disappears due to proximity. But I do not see any logic in this.

I am currently using:

/*
 * Set the camera position (View matrix)
 */
Matrix.setLookAtM(mViewMatrix, offset, eyeX, eyeY, eyeZ / mZoomLevel,
                  centerX, centerY, centerZ, upX, upY, upZ);

where mZoomLevel is the factor that I get through onTouch Scaling.

All my operations with matrices are displayed here:

@Override
public void onDrawFrame(GL10 unused) {

LoggerHelper.calculateFPS();

/*
 * Draw background color
 */
 GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);

/*
 * scale model down to smaller values
 */
Matrix.setIdentityM(mModelMatrix, 0);
Matrix.scaleM(mModelMatrix, 0, model3d.getRatio() * scaleFactor,
                model3d.getRatio() * scaleFactor, model3d.getRatio()
                                * scaleFactor);

/*
 * rotate and translate model in dependence to the user input
 */
Matrix.translateM(mModelMatrix, 0, translateX, translateY, translateZ);
Helper.rotateModel(mModelMatrix, rotationX, rotationY, rotationZ, true,
                model3d.getWidth(), model3d.getLength(), model3d.getHeight());

/*
 * Set the camera position (View matrix)
 */
Matrix.setLookAtM(mViewMatrix, offset, eyeX, eyeY, eyeZ / mZoomLevel,
                centerX, centerY, centerZ, upX, upY, upZ);

/*
 * combine the model with the view matrix
 */
Matrix.multiplyMM(mMVMatrix, 0, mViewMatrix, 0, mModelMatrix, 0);

/*
 * this projection matrix is applied to object coordinates in the
 * onDrawFrame() method
 */
Matrix.frustumM(mProjectionMatrix, 0, -ratio, ratio, 1, -1,
                nearPlaneDistance, farPlaneDistance);

/*
 * Calculate the projection and view transformation
 */
float[] mMVPMatrix = new float[16];
Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVMatrix, 0);

/*
 * all the drawing stuff inside the model-object (otherwise
 * translation/rotation wouldn't affect every object)
 */
model3d.draw(mMVPMatrix);

}

Any important variables:

private float nearPlaneDistance = 1f;
private float farPlaneDistance = 200f;
private float eyeZ = -1;

I downloaded a dummy project with only the OpenGL part in Github - if you want to study the source code better

:

:

Answer 1

( ):

public void setZoom(float zoom) {
    // this projection matrix is applied to object coordinates
    // in the onDrawFrame() method
    float ratio = (float) width / height;
    Matrix.frustumM(mProjectionMatrix, 0, -ratio / zoom, ratio / zoom, -1
            / zoom, 1 / zoom, nearPlaneDistance, farPlaneDistance);
}

(. )

Answer 2

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frustumM. , x y , . , , ( ) , (1 ) .

public static void frustumM(float[] m, int offset,
        float left, float right, float bottom, float top,
        float near, float far) {
    if (left == right) {
        throw new IllegalArgumentException("left == right");
    }
    if (top == bottom) {
        throw new IllegalArgumentException("top == bottom");
    }
    if (near == far) {
        throw new IllegalArgumentException("near == far");
    }
    if (near <= 0.0f) {
        throw new IllegalArgumentException("near <= 0.0f");
    }
    if (far <= 0.0f) {
        throw new IllegalArgumentException("far <= 0.0f");
    }
    final float r_width  = 1.0f / (right - left);
    final float r_height = 1.0f / (top - bottom);
    final float r_depth  = 1.0f / (near - far);
    final float x = 2.0f * (near * r_width);
    final float y = 2.0f * (near * r_height);
    final float A = 2.0f * ((right + left) * r_width);
    final float B = (top + bottom) * r_height;
    final float C = (far + near) * r_depth;
    final float D = 2.0f * (far * near * r_depth);
    m[offset + 0] = x;
    m[offset + 5] = y;
    m[offset + 8] = A;
    m[offset +  9] = B;
    m[offset + 10] = C;
    m[offset + 14] = D;
    m[offset + 11] = -1.0f;
    m[offset +  1] = 0.0f;
    m[offset +  2] = 0.0f;
    m[offset +  3] = 0.0f;
    m[offset +  4] = 0.0f;
    m[offset +  6] = 0.0f;
    m[offset +  7] = 0.0f;
    m[offset + 12] = 0.0f;
    m[offset + 13] = 0.0f;
    m[offset + 15] = 0.0f;
}