Can someone help to make a static analogue clock in OpenGL 2.0 using Java? I used Bresenham Circle to draw a circle for the clock but is there any other way to draw a circle here? Then I drew an hour, minute, and second hand but I got an error in the render part while drawing the numbers. Can someone help me here with how to fix this? The code which I tried is following:
public class MyClock implements GLEventListener {
private int windowWidth = 1000;
private int windowHeight = 900;
public void display(GLAutoDrawable drawable) {
render(drawable);
}
//render
private void render(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
gl.glPointSize(5.0f);
//drawing circle
bresenhamCircle(new Point(100,100), 200, new Color(1, 0, 1), gl);
double x, y, d, delta_SE, delta_E;
x = 0;
double r = 200;
y = r;
d = 5-4*r;
setPixel(x ,y, gl);
setPixel(-x,y, gl);
setPixel(x,-y, gl);
setPixel(-x,-y, gl);
setPixel(y,x, gl);
setPixel(-y,x, gl);
setPixel(y,-x, gl);
setPixel(-y,-x, gl);
while (y>x) {
if (d >= 0) {
delta_SE = 4*(2*(x-y)+5);
d+=delta_SE; x++; y--;
}
else {
delta_E = 4*(2*x+3);
d+=delta_E; x++;
}
setPixel(x,y, gl);
setPixel(-x,y, gl);
setPixel(x,-y, gl);
setPixel(-x,-y, gl);
setPixel(y,x, gl);
setPixel(-y,x, gl);
setPixel(y,-x, gl);
setPixel(-y,-x, gl);
}
//hour hand
gl.glColor3d(0, 0, 1);
gl.glBegin(GL2.GL_LINES);
gl.glVertex2d(0, 00);
gl.glVertex2d(70, 70);
gl.glEnd();
//minute hand
gl.glColor3d(0, 0, 1);
gl.glBegin(GL2.GL_LINES);
gl.glVertex2d(0, 00);
gl.glVertex2d(150, 20);
gl.glEnd();
//seconds hand
gl.glColor3d(1, 0, 0);
gl.glBegin(GL2.GL_LINES);
gl.glVertex2d(0, 00);
gl.glVertex2d(120, -120);
gl.glEnd();
//drawing numbers
int AngleX, AngleY;
int radius;
double line;
for (int i=1;i<=12;i++) {
line = i/12*Math.PI*2;
radius=170;
AngleX=(int)((0)+(Math.sin(line)*radius));
AngleY=(int)((0)+(Math.cos(line)*radius));
gl.glColor3d(1, 1, 1);
String a= Integer.toString(i);
g.drawString(a,AngleX,AngleY);
}
}
//Bresenham Circle method
public void bresenhamCircle(Point center, double radius, Color color, GL2 gl) {
gl.glColor3d(0, 0, 1);
gl.glBegin(GL2.GL_POINTS);
gl.glVertex2d(00,200);
gl.glEnd();
}
private void setPixel(double x, double y,GL2 gl) {
gl.glColor3d(0.0, 1.0, 0.0);
gl.glBegin(GL2.GL_POINTS);
gl.glVertex2d(0,0);
gl.glVertex2d( x, y);
gl.glEnd();
}
public void dispose(GLAutoDrawable drawable) {
}
public void init(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glViewport(0, 0, windowWidth, windowHeight);
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glLoadIdentity();
gl.glOrtho(-windowWidth / 2, windowWidth / 2, -windowHeight / 2, windowHeight / 2, 0, 1);
gl.glClear(GL2.GL_COLOR_BUFFER_BIT);
gl.glEnable(GL2.GL_LINE_SMOOTH);
}
public void reshape(GLAutoDrawable drawable, int x, int y, int w, int h) {
GL2 gl = drawable.getGL().getGL2();
windowWidth = w;
windowHeight = h;
gl.glViewport(0, 0, w, h);
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glLoadIdentity();
gl.glOrtho(-w / 2, w / 2, -h / 2, h / 2, 0, 1);
}
}
As far as I know, there isn't a simple method built into OpenGL ES 2.0 that draws text. That means you have to either find an open-source library that you can use, or you can create your own way of rendering text. This post outlines nicely the different ways that you can render text with OpenGL.
The best way I have found based on my research and which is also stated in the above link, is to render text through images. This tutorial shows how to create a basic text engine and is what I used to get an idea of how to render custom text. The idea is to take a texture atlas (a texture atlas is one image that contains all the letters, numbers, characters that you want to be able to render) and based on what string you want to draw, the engine will crop out the necessary letters, numbers, or characters from the atlas needed for your string and combine them into a square polygon that you can then render to the screen. The tutorial that I linked is a basic text engine, but once you understand how it works, you can then modify and improve it to your needs.
Related
I am currently learning jogl so I can make my own 2d game. All the textures for the tiles are stored in a single large tileset.
I tried to use Texture.getSubImageTexCoords() to draw a single tile, but the result was weird:
I'm not sure exactly how to describe it, but the upper left triangle that makes up the quad is stretching in a very strange way.
I want to display just a section of the tileset.
I tried looking for something online but couldn't find anything.
here is my code:
public class TestSubImage {
private GLU glu = new GLU();
private GLCanvas mainCanvas;
private Texture texture;
private TextureCoords tc;
class Listener implements GLEventListener {
public void init(GLAutoDrawable drawable) {
// Load texture
try {
texture = TextureIO.newTexture(TestSubImage.class.getResource("/images/sheet.png"), false, null);
texture.setTexParameteri(drawable.getGL(), drawable.getGL().GL_TEXTURE_MAG_FILTER, drawable.getGL().GL_NEAREST);
tc = texture.getSubImageTexCoords(0, 16, 16, 32); // sub texture coords
} catch (IOException e) {
e.printStackTrace();
}
// Set up
drawable.getGL().glClearColor(0.3f, 0.3f, 0.3f, 0);
glu = new GLU();
glu.gluOrtho2D(0, 512, 512, 0);
}
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
}
public void dispose(GLAutoDrawable drawable) {
}
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
// where to draw the image
int x = 100;
int y = 100;
int width = 200;
int height = 200;
gl.glColor3f(1, 1, 1);
// Draw the image
texture.enable(gl);
texture.bind(gl);
gl.glBegin(GL2.GL_QUADS);
gl.glVertex2f(x, y);
gl.glTexCoord2f(tc.left(), tc.bottom());
gl.glVertex2f(x, y + height);
gl.glTexCoord2f(tc.right(), tc.bottom());
gl.glVertex2f(x + width, y + height);
gl.glTexCoord2f(tc.right(), tc.top());
gl.glVertex2f(x + width, y);
gl.glTexCoord2f(tc.left(), tc.top());
gl.glEnd();
texture.disable(gl);
}
}
private void run() {
// Create window
JFrame frame = new JFrame("Texture Coords Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create profile and capabilities
final GLProfile profile = GLProfile.get(GLProfile.GL2);
GLCapabilities caps = new GLCapabilities(profile);
// Now set up the main GLCanvas
mainCanvas = new GLCanvas(caps);
mainCanvas.addGLEventListener(new Listener());
frame.getContentPane().add(mainCanvas);
frame.setSize(512, 512);
frame.setResizable(false);
frame.setVisible(true);
}
public static void main(String[] args) {
new TestSubImage().run();
}
}
The tileset is here.
glTexCoord2f sets the texcoord for the next vertex. So, you are rendering one vertex with the default texcoord (whatever that is), and then you are rendering each vertex with the previous vertex's texcoord. And the last texcoord call does nothing. (Well, it probably hangs around as the current texcoord and gets used for the first vertex on the next frame)
You need to call glTexCoord2f before glVertex2f.
P.S. It works the same for glColor3f/4f, glNormal3f, etc.
I don't use JOGL, but it looks like your
gl.glVertex2f(x, y);
gl.glTexCoord2f(tc.left(), tc.bottom());
gl.glVertex2f(x, y + height);
gl.glTexCoord2f(tc.right(), tc.bottom());
gl.glVertex2f(x + width, y + height);
gl.glTexCoord2f(tc.right(), tc.top());
gl.glVertex2f(x + width, y);
gl.glTexCoord2f(tc.left(), tc.top());
is incorrect. If we are pairing each glVertex2f with the line below it I would imagine it should look like
gl.glVertex2f(x, y);
gl.glTexCoord2f(tc.left(), tc.bottom());
gl.glVertex2f(x, y + height);
gl.glTexCoord2f(tc.left(), tc.top());
gl.glVertex2f(x + width, y + height);
gl.glTexCoord2f(tc.right(), tc.top());
gl.glVertex2f(x + width, y);
gl.glTexCoord2f(tc.right, tc.bottom());
This probably sounds weird, but somehow my program just ignores green color
First, I init GL like this: (I don't know, maybe it does matter)
private static void initgl() {
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 1280, 720, 0, 1, -1);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_TEXTURE_2D);
}
I'm drawing a square like this:
public static void gameLoop(){
while (!Display.isCloseRequested()){
glClear(GL_COLOR_BUFFER_BIT);
DrawStuff.square(10, 10, 100, 100, new byte[]{127,127,127});
Display.update();
Display.sync(60);
}
}
and in square method I have
public static void square(int x, int y, int w, int h, byte[] rgb) {
glColor3b(rgb[0], rgb[1], rgb[2]);
glBegin(GL_QUADS);
glVertex2i(x, y);
glVertex2i(x + w, y);
glVertex2i(x + w, y + h);
glVertex2i(x,y+h);
glEnd();
}
When I run the program, I see this:
And by the way, color picker says it's #C808C7 . Not even #FF00FF like I expected
what happened to the green color?
why colors are off?
Ok, this answer helped me: How do color and textures work together?
That's not your problem, but it still needs to be done.
What was messing with my colors is glEnable(GL_TEXTURE_2D); To achieve both color and texture filling I have to disable it each time I want to draw something with solid color and then enable again:
public static void square(int x, int y, int w, int h, byte[] rgb) {
glDisable(GL_TEXTURE_2D);
glColor3b(rgb[0], rgb[1], rgb[2]);
glBegin(GL_QUADS);
glVertex2i(x, y);
glVertex2i(x + w, y);
glVertex2i(x + w, y + h);
glVertex2i(x,y+h);
glEnd();
glEnable(GL_TEXTURE_2D);
}
Depending on your case, future reader, you may want to keep it disabled in the first place, only enabling it if you need to add textures.
Volia:
I'm currently trying to make a game, and I'm still novice with using cameras, and I'm thinking that two OrthographicCameras may be necessary, but I'm not sure if that's the most efficient way, or even how to do so.
Basically, I want this to be the layout for it:
The Main Area is where the main stuff is, which is a Server Interface. The Game Level is where the actual game part is in. I am currently using a ScissorStack to cut the region, but with this demo, results make me question how to do this:
public class TestScissorStackAndCamera extends ApplicationAdapter {
private SpriteBatch batch;
private OrthographicCamera camera;
private Sprite sprite;
private int width, height;
#Override
public void create() {
Gdx.gl.glClearColor(0, 0, 0, 0);
width = Gdx.graphics.getWidth();
height = Gdx.graphics.getHeight();
batch = new SpriteBatch();
camera = new OrthographicCamera(width, height);
camera.position.set(width / 2, height / 2, 0);
camera.update();
createSprite();
}
private void createSprite() {
Pixmap map = new Pixmap(width, height, Format.RGBA8888);
map.setColor(Color.RED);
map.fillRectangle(0, 0, width, height);
map.setColor(Color.BLUE);
map.drawLine(width / 2, 0, width / 2, height);
map.drawLine(0, height / 2, width, height / 2);
Texture texture = new Texture(map);
sprite = new Sprite(texture);
}
#Override
public void render() {
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.setProjectionMatrix(camera.combined); // The Question!
batch.begin();
{
Rectangle scissors = new Rectangle();
Rectangle area = new Rectangle(10, 10, width - 20, height - 20);
ScissorStack.calculateScissors(camera, batch.getTransformMatrix(), area, scissors);
ScissorStack.pushScissors(scissors);
batch.draw(sprite, 0, 0);
batch.flush();
ScissorStack.popScissors();
}
batch.end();
}
public static void main(String[] args) {
LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();
config.title = "ScissorStack & Camera Test";
config.resizable = false;
new LwjglApplication(new TestScissorStackAndCamera(), config);
}
}
Questioning batch.setProjectionMatrix(camera.combined)
I marked a line in the code with a comment, The Question!, which is what is affecting the results. If I don't have it, using the camera.translate(...) method, the image is drawn at (0, 0) but what it does is it moves what part is viewed. If I do have that line, when I use the camera.translate(...) method, the image is drawn respectively to the position of the camera.
In respect to the game that I'm currently developing, it behaves awkwardly without the projectionMatrix not being set, but when I do set it, it messes up the positioning of the rest of the game. I even added some testing features, and it's not rendering inside of the correct ScissorStack
How could I go about setting up two cameras, or what could I do to set up what I'm trying to correctly and efficiently?
With my actual game (not the mock-up) this is what it is doing. It should be rendering inside of the red lines, but it's not:
If you'd like to see my current code for my GameLevel that is handling the ScissorStack and OrthographicCamera:
public GameLevel(int x, int y, int displayWidth, int displayHeight) {
this.x = x; // x = 10
this.y = y; // y = 10
this.displayWidth = displayWidth; // displayWidth = Gdx.graphics.getWidth() - x - 10
this.displayHeight = displayHeight; // displayHeight = Gdx.graphics.getHeight() - y - 120
camera = new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.position.set(displayWidth / 2, displayHeight / 2, 0);
// FBLAGame.batch.setProjectionMatrix(camera.combined);
camera.update();
init();
}
...
#Override
public void render() {
Rectangle area = new Rectangle(x, y, displayWidth, displayHeight);
Rectangle scissor = new Rectangle();
Matrix4 matrix = FBLAGame.batch.getTransformMatrix();
ScissorStack.calculateScissors(camera, matrix, area, scissor);
ScissorStack.pushScissors(scissor);
renderLevel();
FBLAGame.batch.flush();
ScissorStack.popScissors();
Pixmap map = new Pixmap(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), Format.RGBA8888);
map.setColor(Color.RED);
map.drawRectangle((int) area.x, (int) area.y, (int) area.width, (int) area.height);
Texture t = new Texture(map);
map.dispose();
FBLAGame.batch.draw(t, 0, 0);
}
I met some problems about jogl picking. I need to pick each single point and process it, but I always get 0 hit (nothing is picked). Can anyone help me with this?
the display function can correctly get the 2x2 window around the cursor.
public void display(GLAutoDrawable drawable) {
GL2 gl = drawable.getGL().getGL2();
switch(cmd){
case UPDATE:
gl.glPushMatrix();
gl.glMultMatrixf(rot_matrix, 0);
buildPoints(gl);
buildAxes(gl);
gl.glPopMatrix();
break;
case SELECT:
int buffsize = 512;
double x = mouseX, y = mouseY;
int[] viewPort = new int[4];
IntBuffer selectBuffer = Buffers.newDirectIntBuffer(buffsize);
int hits = 0;
gl.glGetIntegerv(GL2.GL_VIEWPORT, viewPort, 0);
gl.glSelectBuffer(buffsize, selectBuffer);
gl.glRenderMode(GL2.GL_SELECT);
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glPushMatrix();
gl.glLoadIdentity();
glu.gluPickMatrix(x, (double) viewPort[3] - y, 2.0d, 2.0d, viewPort, 0);
//draw graph
gl.glPushMatrix();
gl.glMultMatrixf(rot_matrix, 0);
buildPoints(gl);
buildAxes(gl);
gl.glPopMatrix();
gl.glMatrixMode(GL2.GL_PROJECTION);
gl.glPopMatrix();
gl.glMatrixMode(GL2.GL_MODELVIEW);
gl.glFlush();
hits = gl.glRenderMode(GL2.GL_RENDER);
processHits(hits, selectBuffer);
cmd = UPDATE;
break;
}
}
so I guess maybe the drawing graph part for picking is not correct. Here is the code of buildPoints function.
public void buildPoints(GL2 gl) {
gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
gl.glPointSize((float) radius / 2);
int pointName = 0;
gl.glBegin(GL.GL_POINTS);
for (point p : pointsList) {
if(cmd == SELECT) gl.glLoadName(pointName);
gl.glPushMatrix();
gl.glTranslatef(p.getX(), p.getY(), p.getZ());
gl.glColor3f(0.95f, 0.207f, 0.031f);
gl.glVertex3f((float) (p.getX() * scaleFactor),
(float) (p.getY() * scaleFactor),
(float) (p.getZ() * scaleFactor));
gl.glPopMatrix();
pointName++;
}
gl.glEnd();
}
I advise you to look at this example of picking using JOGL 2. However, OpenGL build-in picking is deprecated and shouldn't be used. We discussed a lot about it on our official forum, especially in this thread.
I have built a very nice Rubik's Cube in OpenGl for my android application. Unfortunately it looks a bit stretched when I bring it closer to the camera. It looks like this:
I'd like to have my Cube as big as it could possibly be on my screen, but without that stretching.
Here is a bit of code:
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
float z = 3;
float x = 0;
float y = 3;
GLU.gluLookAt(gl, x, y, z, 0, 0, 0, 0, 1, 0);
I tried to work with GLU.gluPerspective() but it did not work.
EDIT: Here is more code from my renderer class:
#Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
gl.glDisable(GL10.GL_DITHER);
gl.glClearColor(0, 0, 0, 0);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glClearDepthf(1f);
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthFunc(GL10.GL_LEQUAL);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
}
#Override
public void onDrawFrame(GL10 gl) {
gl.glDisable(GL10.GL_DITHER);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
float z = 3;
float x = 0;
float y = 3;
GLU.gluLookAt(gl, x, y, z, 0, 0, 0, 0, 1, 0);
gl.glRotatef(angleX, 1, 0, 0); //This is the rotation if surface is touched
gl.glRotatef(angleY, 0, 1, 0);
f.draw(gl); //drawing the pieces of the cube
r.draw(gl);
l.draw(gl);
u.draw(gl);
d.draw(gl);
b.draw(gl);
for (int i = 0; i < corners.length; i++) {
corners[i].draw(gl);
}
for (int i = 0; i < edges.length; i++) {
edges[i].draw(gl);
}
display(); //this has nothing to do with opengl
}
#Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 25);
}
The camera is too near to the object. Try moving the camera backwards a bit, and the near plane a bit back. (5th parameter to glFrustumf).