/**
* //! Draw a pretty arrow on the z-axis using a cone and a cylinder (using GLUT)
*
* @param aArrowStart
* @param aArrowTip
* @param aWidth
*/
public static void jDrawArrow(
final JVector3d aArrowStart, final JVector3d aArrowTip, final double aWidth) {
GL2 gl = GLContext.getCurrent().getGL().getGL2();
gl.glPushMatrix();
// We don't really care about the up vector, but it can't
// be parallel to the arrow...
JVector3d up = new JVector3d(0, 1, 0);
// JVector3d arrow = aArrowTip-aArrowStart;
JVector3d arrow = new JVector3d(0, 0, 0);
arrow.normalize();
double d = Math.abs(JMaths.jDot(up, arrow));
if (d > .9) {
up = new JVector3d(1, 0, 0);
}
JMatrixGL.jLookAt(gl, aArrowStart, aArrowTip, up);
double distance = JMaths.jDistance(aArrowTip, aArrowStart);
// This flips the z axis around
gl.glRotatef(180, 1, 0, 0);
// create a new OpenGL quadratic object
GLUquadric quadObj;
quadObj = glu.gluNewQuadric();
// set rendering style
glu.gluQuadricDrawStyle(quadObj, GLU.GLU_FILL);
// set normal-rendering mode
glu.gluQuadricNormals(quadObj, GLU.GLU_SMOOTH);
// render a cylinder and a cone
gl.glRotatef(180, 1, 0, 0);
glu.gluDisk(quadObj, 0, aWidth, 10, 10);
gl.glRotatef(180, 1, 0, 0);
glu.gluCylinder(quadObj, aWidth, aWidth, distance * ARROW_CYLINDER_PORTION, 10, 10);
gl.glTranslated(0, 0, ARROW_CYLINDER_PORTION * distance);
gl.glRotatef(180, 1, 0, 0);
glu.gluDisk(quadObj, 0, aWidth * 2.0, 10, 10);
gl.glRotatef(180, 1, 0, 0);
glu.gluCylinder(quadObj, aWidth * 2.0, 0.0, distance * ARRROW_CONE_PORTION, 10, 10);
// delete our quadric object
glu.gluDeleteQuadric(quadObj);
gl.glPopMatrix();
}
/**
* Build a 4x4 matrix transform, according to the gluLookAt function.
*
* @param aEye
* @param aLookAt
* @param aUp
*/
public void buildLookAtMatrix(JVector3d aEye, JVector3d aLookAt, JVector3d aUp) {
buildLookAtMatrix(
aEye.getX(),
aEye.getY(),
aEye.getZ(),
aLookAt.getX(),
aLookAt.getY(),
aLookAt.getZ(),
aUp.getX(),
aUp.getY(),
aUp.getZ());
}
/**
* Creates OpenGL translation matrix from a position vector passed as parameter.
*
* @param aPos
*/
public void set(final JVector3d aPos) {
m[0][0] = 1.0;
m[0][1] = 0.0;
m[0][2] = 0.0;
m[0][3] = 0.0;
m[1][0] = 0.0;
m[1][1] = 1.0;
m[1][2] = 0.0;
m[1][3] = 0.0;
m[2][0] = 0.0;
m[2][1] = 0.0;
m[2][2] = 1.0;
m[2][3] = 0.0;
m[3][0] = aPos.getX();
m[3][1] = aPos.getY();
m[3][2] = aPos.getZ();
m[3][3] = 1.0;
}
/**
* Create an OpenGL translation matrix from a 3-vector and a 3x3 matrix passed as a parameter.
*
* @param aPos
* @param aRot
*/
public void set(final JVector3d aPos, final JMatrix3d aRot) {
m[0][0] = aRot.m[0][0];
m[0][1] = aRot.m[1][0];
m[0][2] = aRot.m[2][0];
m[0][3] = 0.0;
m[1][0] = aRot.m[0][1];
m[1][1] = aRot.m[1][1];
m[1][2] = aRot.m[2][1];
m[1][3] = 0.0;
m[2][0] = aRot.m[0][2];
m[2][1] = aRot.m[1][2];
m[2][2] = aRot.m[2][2];
m[2][3] = 0.0;
m[3][0] = aPos.getX();
m[3][1] = aPos.getY();
m[3][2] = aPos.getZ();
m[3][3] = 1.0;
}
public static void jLookAt(GL2 gl, JVector3d eye, JVector3d at, JVector3d up) {
// Define our look vector (z axis)
JVector3d look = at.operatorSub(eye);
look.normalize();
// Define our new x axis
JVector3d xaxis = JMaths.jCross(look, up);
xaxis.normalize();
// Define our new y axis as the cross of the x and z axes
JVector3d upv = JMaths.jCross(xaxis, look);
// Turn around the z axis
look.mul(-1.0);
// Put it all into a GL-friendly matrix
double[] dm = new double[16];
dm[0] = xaxis.getX();
dm[1] = xaxis.getY();
dm[2] = xaxis.getZ();
dm[3] = 0.f;
dm[4] = upv.getX();
dm[5] = upv.getY();
dm[6] = upv.getZ();
dm[7] = 0.f;
dm[8] = look.getX();
dm[9] = look.getY();
dm[10] = look.getZ();
dm[11] = 0.f;
dm[12] = eye.getX();
dm[13] = eye.getY();
dm[14] = eye.getZ();
dm[15] = 1.f;
// Push it onto the matrix stack
gl.glMultMatrixd(dm, 0);
}