I am trying to load earth.png and place it over a triangle. The image is 256x256. I have followed an online tutorial and played around with this for hours, but the triangle still remains white. Can any one point me in the right direction.
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.io.InputStream;
import javax.media.opengl.*;
import javax.medi开发者_StackOverflow中文版a.opengl.awt.GLCanvas;
import com.jogamp.opengl.util.texture.Texture;
import com.jogamp.opengl.util.texture.TextureData;
import com.jogamp.opengl.util.texture.TextureIO;
public class test implements GLEventListener {
private Texture earthTexture;
public static void main(String[] args) {
GLProfile glp = GLProfile.getDefault();
GLCapabilities caps = new GLCapabilities(glp);
GLCanvas canvas = new GLCanvas(caps);
final Frame frame = new Frame("AWT Window Test111");
frame.setSize(700, 700);
frame.add(canvas);
frame.setVisible(true);
// by default, an AWT Frame doesn't do anything when you click
// the close button; this bit of code will terminate the program when
// the window is asked to close
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
frame.dispose();
System.exit(0);
}
});
canvas.addGLEventListener(new test());
}
@Override
public void display(GLAutoDrawable arg0) {
update();
render(arg0);
}
private void update() {
// TODO Auto-generated method stub
}
private void render(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glClear(GL.GL_COLOR_BUFFER_BIT);
gl.glEnable(GL.GL_TEXTURE_2D);
gl.glBegin(GL2.GL_TRIANGLES); // Begin drawing triangle sides
earthTexture.enable();
earthTexture.bind();
// gl.glColor3f( 1.0f, 0.0f, 0.0f); // Set colour to red
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f( 0.0f, 1.0f, 1.0f); // Top vertex
gl.glTexCoord2f(-1.0f, -2.0f);
gl.glVertex3f(-1.0f,-1.0f, 0.0f); // Bottom left vertex
gl.glTexCoord2f(1.0f, -2.0f);
gl.glVertex3f( 1.0f,-1.0f, 0.0f); // Bottom right vertex
gl.glEnd();
}
@Override
public void dispose(GLAutoDrawable arg0) {
// TODO Auto-generated method stub
}
@Override
public void init(GLAutoDrawable arg0) {
GL2 gl = arg0.getGL().getGL2();
// Load texture.
try {
InputStream stream = getClass().getResourceAsStream("earth.png");
TextureData data = TextureIO.newTextureData(gl.getGLProfile(), stream, 100, 200, false, "png");
earthTexture = TextureIO.newTexture(data);
}
catch (IOException exc) {
exc.printStackTrace();
System.exit(1);
}
}
@Override
public void reshape(GLAutoDrawable arg0, int arg1, int arg2, int arg3,
int arg4) {
// TODO Auto-generated method stub
}
}
You are binding your texture in between the glBegin/glEnd statements. It is required to do so before the glBegin. Texture switches in between begin/end pairs are likely to be ignored.
A couple of things I have noticed:
You need to explicitly enable texturing within OpenGL, by using something like:
gl.glEnable(GL.GL_TEXTURE_2D);
You also will need to specify coordinates for the textures (typically expressed as u,v coordinates), this needs to be done for every 3D point:
gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f( 0.0f, 1.0f, 1.0f);
...
The excellent NeHe tutorials also have JOGL sample code these days, which will be worthwhile looking at in more depth:
http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=07
This article also has some good information on understanding texture coordiantes:
http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node52.html
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