/* SplineCurves.java * * This displays three multisegment bezier curves. * The first uses two segments to make a curly bracket, drawn in black. * * The second uses a small set of control points to make a closed * curve that looks like a circle, which is drawn in red. * * The third plots 3N+1 control points exactly on a circle to * allow for N Bezier segments. This is drawn in green. * * All of these are drawn in the y-z plane, with the x-axis coming * out at the viewer. The viewer is at (10, 0, 0) looking at the origin. */ import java.awt.FlowLayout; import java.awt.Frame; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.media.opengl.*; import javax.media.opengl.glu.*; import javax.media.opengl.awt.GLCanvas; import com.jogamp.opengl.util.*; import java.awt.*; import javax.swing.*; import java.awt.event.*; import java.nio.FloatBuffer; import javax.swing.event.*; public class SplineCurves implements GLEventListener, ActionListener, ChangeListener { public static void main(String[] args) { new SplineCurves(); } private int INITIAL_WIDTH=800; private int INITIAL_HEIGHT=800; JButton quitButton; private GLCanvas canvas; private GL2 gl; private GLU glu; private GLUquadric quad; /* 7 control points gives 2 Bezier segments */ private float [][] data1= { {0, -3, 0}, {0, -2, 4}, {0, -1, 0}, {0, 0, 3}, {0, 1, 2}, {0, 2, 3}, {0, 3, 4} }; /* The following makes a closed curve; if you inscribe this in a box * it will be tangent to each of the sizes of the box. This makes * 4 Bezier segments. The figure is drawn in red. */ private float [][] data2 = { {0, -2, 0},{0, -2, 1},{0, -1, 2}, {0, 0, 2}, {0, 1, 2}, {0, 2, 1}, {0, 2, 0}, {0, 2, -1}, {0, 1, -2}, {0, 0, -2}, {0, -1, -2}, {0, -2, -1}, {0, -2, 0}}; private float [][] data3; private float [] buffer1; private float [] buffer2; private float [] buffer3; private static final int N = 20; private static final int SIZE = 3*N+1; public SplineCurves() { GLProfile glp=GLProfile.getDefault(); GLCapabilities caps = new GLCapabilities(glp); canvas = new GLCanvas(caps); canvas.addGLEventListener(this); JFrame frame = new JFrame("SPLINE CURVES"); frame.setSize(INITIAL_WIDTH, INITIAL_HEIGHT); frame.setLayout(new BorderLayout()); JPanel north = new JPanel( new FlowLayout()); quitButton = new JButton( "Quit"); quitButton.addActionListener(this); north.add(quitButton);; frame.add(north, BorderLayout.NORTH); JPanel myCanvas = new JPanel(new GridLayout(1,1)); myCanvas.add(canvas); frame.add(myCanvas, BorderLayout.CENTER); frame.setVisible(true); FPSAnimator animator = new FPSAnimator(canvas, 60); animator.start(); } public void actionPerformed(ActionEvent event) { if (event.getSource() == quitButton) System.exit(0); } public void stateChanged(ChangeEvent e) { } /* This fills in the data2 array with enough control points * to ake N Bezier segments, with the control points lying on a * circle of radius r. */ public void buildCircle(float r) { data3 = new float[SIZE][3]; float angle = (float)(2*Math.PI/(SIZE-1)); for (int i = 0; i < SIZE; i++) { data3[i][0] = 0; data3[i][1] = (float)(r*Math.cos(i*angle)); data3[i][2] = (float)(r*Math.sin(i*angle)); } } public void display(GLAutoDrawable drawable) { update(); render(); } private void update() { } private void render() { gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT); gl.glColor3f( 0, 0, 0); /* FIRST BLACK SEGMENT: */ gl.glMap1f(GL2.GL_MAP1_VERTEX_3, 0, 1, 3, 4, FloatBuffer.wrap(buffer1, 0, 12)); gl.glMapGrid1f(10, 0, 1); gl.glEvalMesh1(GL2.GL_LINE, 0, 10); /* SECOND BLACK SEGMENT */ gl.glMap1f(GL2.GL_MAP1_VERTEX_3, 0, 1, 3, 4, FloatBuffer.wrap(buffer1, 9, 12)); gl.glMapGrid1f(10, 0, 1); gl.glEvalMesh1(GL2.GL_LINE, 0, 10); /* RED CIRCLE with 4 segments */ gl.glPushMatrix(); gl.glTranslatef(0, -3, -3); gl.glPushMatrix(); gl.glRotatef(90, 0, 1, 0); gl.glColor3f(0.7f,0.7f,0.7f); glu.gluDisk(quad, 0.0, 1.9, 360, 16); gl.glPopMatrix(); gl.glColor3f( 1, 0, 0); for (int i = 0; i < 4; i++ ) { gl.glMap1f(GL2.GL_MAP1_VERTEX_3, 0, 1, 3, 4, FloatBuffer.wrap(buffer2, 9*i, 12)); gl.glMapGrid1f(10, 0, 1); gl.glEvalMesh1(GL2.GL_LINE, 0, 10); } gl.glPopMatrix(); /* GREEN CIRCLE, WITH N=20 SEGMENTS */ gl.glPushMatrix(); gl.glTranslatef(0, 3, -3); gl.glColor3f(0.7f,0.7f,0.7f); gl.glPushMatrix(); gl.glRotatef(90, 0, 1, 0); gl.glColor3f(0.7f,0.7f,0.7f); glu.gluDisk(quad, 0.0, 1.9, 360, 16); gl.glPopMatrix(); gl.glColor3f( 0, 1, 0); for (int i = 0; i < N; i++ ) { gl.glMap1f(GL2.GL_MAP1_VERTEX_3, 0, 1, 3, 4, FloatBuffer.wrap(buffer3, 9*i, 12)); gl.glMapGrid1f(10, 0, 1); gl.glEvalMesh1(GL2.GL_LINE, 0, 10); } gl.glPopMatrix(); } public void dispose(GLAutoDrawable drawable) { // put the cleanup code here } public float [] buildBuffer(float[][] data) { /* This copies points from our data arrays into the buffers in a form * that glMap1 is happy with. */ float [] buffer = new float[data.length*3]; for (int i = 0; i < data.length; i++) for (int j = 0; j < 3; j++) buffer[i*3+j] = data[i][j]; return buffer; } public void init(GLAutoDrawable drawable) { gl = drawable.getGL().getGL2(); glu = new GLU(); gl.glEnable(GL2.GL_DEPTH_TEST); gl.glEnable(GL2.GL_MAP1_VERTEX_3); gl.glMatrixMode(GL2.GL_PROJECTION); gl.glLoadIdentity(); glu.gluPerspective(60f, 1, 0.5f, 20); gl.glMatrixMode(GL2.GL_MODELVIEW); gl.glLoadIdentity(); glu.gluLookAt(10,0,0, 0,0,0, 0,0,1); gl.glClearColor(1f, 1f, 1f, 1f); gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT); buildCircle(2); buffer1 = buildBuffer(data1); buffer2 = buildBuffer(data2); buffer3 = buildBuffer(data3); quad = glu.gluNewQuadric(); } public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) { // this is called when the window is resized gl.glViewport(0, 0, width, height); float aspect = width*1.0f/height; gl.glMatrixMode(GL2.GL_PROJECTION); gl.glLoadIdentity(); glu.gluPerspective(60f, aspect, 0.5f, 200f); gl.glMatrixMode(GL2.GL_MODELVIEW); } }