/**
* Called back immediately after the OpenGL context is initialized. Can be used to perform
* one-time initialization. Run only once.
*/
@Override
public void init(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2(); // get the OpenGL graphics context
glu = new GLU(); // get GL Utilities
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // set background (clear) color
gl.glClearDepth(1.0f); // set clear depth value to farthest
// Do not enable depth test
// gl.glEnable(GL_DEPTH_TEST); // enables depth testing
// gl.glDepthFunc(GL_LEQUAL); // the type of depth test to do
gl.glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // best perspective correction
gl.glShadeModel(GL_SMOOTH); // blends colors nicely, and smoothes out lighting
// Load the texture image
try {
// Use URL so that can read from JAR and disk file.
BufferedImage image = ImageIO.read(this.getClass().getResource(textureFileName));
// Create a OpenGL Texture object
texture = AWTTextureIO.newTexture(GLProfile.getDefault(), image, false);
// Use linear filter if image is larger than the original texture
gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Use linear filter if image is smaller than the original texture
gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
} catch (GLException | IOException e) {
e.printStackTrace();
}
// Texture image flips vertically. Shall use TextureCoords class to retrieve
// the top, bottom, left and right coordinates, instead of using 0.0f and 1.0f.
TextureCoords textureCoords = texture.getImageTexCoords();
textureCoordTop = textureCoords.top();
textureCoordBottom = textureCoords.bottom();
textureCoordLeft = textureCoords.left();
textureCoordRight = textureCoords.right();
// Enable the texture
texture.enable(gl);
texture.bind(gl);
// gl.glEnable(GL_TEXTURE_2D);
// Enable blending
gl.glEnable(GL_BLEND);
gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE);
// Allocate the stars
for (int i = 0; i < stars.length; i++) {
stars[i] = new Star();
// Linearly distributed according to the star number
stars[i].distance = ((float) i / numStars) * 5.0f;
}
}
public void draw() {
// Clear GL state
gl.glDisable(GL_LIGHTING);
gl.glDisable(GL_DEPTH);
gl.glMatrixMode(GL_MODELVIEW);
gl.glPushMatrix();
gl.glLoadIdentity();
gl.glMatrixMode(GL_PROJECTION);
gl.glPushMatrix();
gl.glLoadIdentity();
gl.glClearColor(0.8f, 0.2f, 0.2f, 1.0f);
gl.glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
gl.glPointSize(1.0f);
// Set the viewport
glu.gluOrtho2D(xMin, xMax, yMin, yMax);
gl.glBegin(GL_POINTS);
for (int x = (int) (xMin); x < xMax; x++)
for (int y = (int) (yMin); y < yMax; y++) {
gl.glColor3d(viewPort[x][y].r, viewPort[x][y].g, viewPort[x][y].b);
gl.glVertex2d(x + 0.5, y + 0.5);
}
gl.glEnd();
// Restore state
gl.glMatrixMode(GL_MODELVIEW);
gl.glPopMatrix();
gl.glMatrixMode(GL_PROJECTION);
gl.glPopMatrix();
gl.glEnable(GL_LIGHTING);
gl.glEnable(GL_DEPTH);
}