package fancy.jf.error;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLEventListener;
public class FloatError implements GLEventListener {
private GL gl = null;
private final double sum = 10000;
private final float mv[] = new float[16];
@Override
public void init(GLAutoDrawable drawable) {
gl = drawable.getGL();
gl.glMatrixMode(GL.GL_MODELVIEW);
// --- rounding error orthogonal (java) -------------------------------
javaLoadIdentity();
for (int i = 0; i < sum; i++) {
javaTranslate(1.0f, 0.0f, 0.0f);
}
javaTranslate((float) -sum, 0f, 0f);
System.out.println("rounding error orthogonal (java) : " + mv[3]);
// --------------------------------------------------------------------
// --- rounding error non orthogonal (java) ---------------------------
javaLoadIdentity();
javaRotate(22.2f, 0f, 1f, 0f);
for (int i = 0; i < sum; i++) {
javaTranslate(1.0f, 0.0f, 0.0f);
}
javaTranslate((float) -sum, 0f, 0f);
System.out.println("rounding error non orthogonal (java): " + mv[3]);
// --------------------------------------------------------------------
// --- rounding error orthogonal (gl) ---------------------------------
gl.glLoadIdentity();
for (int i = 0; i < sum; i++) {
gl.glTranslated(1.0, 0.0, 0.0);
}
gl.glTranslated(-sum, 0, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, mv, 0);
System.out.println("rounding error orthogonal (gl) : " + mv[12]);
// --------------------------------------------------------------------
// --- rounding error non orthogonal (gl) -----------------------------
gl.glLoadIdentity();
gl.glRotated(22.2, 0, 1, 0);
for (int i = 0; i < sum; i++) {
gl.glTranslated(1.0, 0.0, 0.0);
}
gl.glTranslated(-sum, 0, 0);
gl.glGetFloatv(GL.GL_MODELVIEW_MATRIX, mv, 0);
System.out.println("rounding error non orthogonal (gl) : " + mv[12]);
// --------------------------------------------------------------------
}
private void javaLoadIdentity() {
for (int i = 0; i < 16; i++)
mv[i] = 0;
for (int i = 0; i < 4; i++)
mv[i * 5] = 1.0f;
}
public void javaTranslate(float x, float y, float z) {
mv[3] = mv[0] * x + mv[1] * y + mv[2] * z + mv[3];
mv[7] = mv[4] * x + mv[5] * y + mv[6] * z + mv[7];
mv[11] = mv[8] * x + mv[9] * y + mv[10] * z + mv[11];
mv[15] = mv[12] * x + mv[13] * y + mv[14] * z + mv[15];
}
public void javaRotate(float angle, float x, float y, float z) {
float[] mvt = new float[16];
float v = (float) Math.sqrt((x * x) + (y * y) + (z * z));
x = x / v;
y = y / v;
z = z / v;
float r = (float) Math.toRadians(angle);
float c = (float) Math.cos(r);
float s = (float) Math.sin(r);
float[] t = new float[9];
t[0] = x * x * (1 - c) + c;
t[1] = x * y * (1 - c) - z * s;
t[2] = x * z * (1 - c) + y * s;
t[3] = y * x * (1 - c) + z * s;
t[4] = y * y * (1 - c) + c;
t[5] = y * z * (1 - c) - x * s;
t[6] = x * z * (1 - c) - y * s;
t[7] = y * z * (1 - c) + x * s;
t[8] = z * z * (1 - c) + c;
mvt[0] = mv[0] * t[0] + mv[1] * t[3] + mv[2] * t[6];
mvt[1] = mv[0] * t[1] + mv[1] * t[4] + mv[2] * t[7];
mvt[2] = mv[0] * t[2] + mv[1] * t[5] + mv[2] * t[8];
mvt[3] = mv[3];
mvt[4] = mv[4] * t[0] + mv[5] * t[3] + mv[6] * t[6];
mvt[5] = mv[4] * t[1] + mv[5] * t[4] + mv[6] * t[7];
mvt[6] = mv[4] * t[2] + mv[5] * t[5] + mv[6] * t[8];
mvt[7] = mv[7];
mvt[8] = mv[8] * t[0] + mv[9] * t[3] + mv[10] * t[6];
mvt[9] = mv[8] * t[1] + mv[9] * t[4] + mv[10] * t[7];
mvt[10] = mv[8] * t[2] + mv[9] * t[5] + mv[10] * t[8];
mvt[11] = mv[11];
mvt[12] = mv[12] * t[0] + mv[13] * t[3] + mv[14] * t[6];
mvt[13] = mv[12] * t[1] + mv[13] * t[4] + mv[14] * t[7];
mvt[14] = mv[12] * t[2] + mv[13] * t[5] + mv[14] * t[8];
mvt[15] = mv[15];
for (int i = 0; i < 16; i++)
mv[i] = (float) (mvt[i]);
}
@Override
public void display(GLAutoDrawable drawable) {}
@Override
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {}
@Override
public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {}
public static void main(String[] args) {
final FloatError main = new FloatError();
final Frame frame = new Frame();
final GLCanvas canvas = new GLCanvas();
canvas.addGLEventListener(main);
frame.add(canvas);
frame.setSize(50, 50);
frame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent e) {
new Thread(new Runnable() {
public void run() {
System.exit(0);
}
}).start();
}
});
frame.setVisible(true);
}
}