TangoUtils.java

package org.wheelmap.android.tango;

import android.opengl.Matrix;

import com.google.atap.tangoservice.Tango;
import com.google.atap.tangoservice.TangoCameraIntrinsics;

import org.wheelmap.android.app.WheelmapApp;

public class TangoUtils {

    public static boolean isTangoSupported() {
        return Tango.getVersion(WheelmapApp.get()) > 0;
    }

    /**
     * Use Tango camera intrinsics to calculate the projection Matrix for the Rajawali scene.
     */
    static float[] projectionMatrixFromCameraIntrinsics(TangoCameraIntrinsics intrinsics) {
        // Uses frustumM to create a projection matrix taking into account calibrated camera
        // intrinsic parameter.
        // Reference: http://ksimek.github.io/2013/06/03/calibrated_cameras_in_opengl/
        float near = 0.1f;
        float far = 100;

        double cx = intrinsics.cx;
        double cy = intrinsics.cy;
        double width = intrinsics.width;
        double height = intrinsics.height;
        double fx = intrinsics.fx;
        double fy = intrinsics.fy;

        double xscale = near / fx;
        double yscale = near / fy;

        double xoffset = (cx - (width / 2.0)) * xscale;
        // Color camera's coordinates has y pointing downwards so we negate this term.
        double yoffset = -(cy - (height / 2.0)) * yscale;

        float m[] = new float[16];
        Matrix.frustumM(m, 0,
                (float) (xscale * -width / 2.0 - xoffset),
                (float) (xscale * width / 2.0 - xoffset),
                (float) (yscale * -height / 2.0 - yoffset),
                (float) (yscale * height / 2.0 - yoffset), near, far);
        return m;
    }

}