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).
Related
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.
In a middle of developing my game I created a function to rotate a 2d triangle.
But the problem is that when I rotate an object, the rotation is very weird.
If the object's center is at the origin (the (0,0) point) of the axis then it rotates fine, but if I move the object then it rotates in a very weird way that it shouldn't be rotating in.
as you can see here is the code of the function.
public void rotate(float angle){
float x1 = x, y1 = y;
float x2 = x + width, y2 = y;
float x3 = x + width, y3 = y + height;
float x4 = x, y4 = y + height;
// Vertices in object space:
float[] vector1 = {x1, y1, 0f, 1f};
float[] vector2 = {x2, y2, 0f, 1f};
float[] vector3 = {x3, y3, 0f, 1f};
float[] vector4 = {x4, y4, 0f, 1f};
// Vertices in world space:
float[] vector1r = new float[4];
float[] vector2r = new float[4];
float[] vector3r = new float[4];
float[] vector4r = new float[4];
// Calculate the vertices in world space:
Matrix.multiplyMV(vector1r, 0, modelMatrix, 0, vector1, 0);
Matrix.multiplyMV(vector2r, 0, modelMatrix, 0, vector2, 0);
Matrix.multiplyMV(vector3r, 0, modelMatrix, 0, vector3, 0);
Matrix.multiplyMV(vector4r, 0, modelMatrix, 0, vector4, 0);
// Get the middle of the rectangle:
float[] vecMid = {(vector1r[0] + vector3r[0]) / 2,
(vector1r[1] + vector3r[1]) / 2, 0f, 1f};
move(vecMid[0], vecMid[1]); // Move to the origin
Matrix.rotateM(modelMatrix, 0, angle, 0, 0, 1f); // Rotate the object
move(-vecMid[0], -vecMid[1]); // Move back to place
if(LoggerConfig.ON)
Log.d("Middle Vertex", vecMid[0] + ", " + vecMid[1]);
}
The move method:
public void move(float x, float y){
Matrix.translateM(modelMatrix, 0, x, y, 0);
}
Can someone tell me what the problem is?
EDIT: I did some modifications to the code and added the move method.
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);
}
The Original Problem:
I'm making a 2d game in OpenGL that uses tiles to draw a map. At the moment, each tile is drawn individually on a quad. The code for the tile rendering is:
#Override
public void render() {
if (parentTileSet.getTexture() == null)
return;
float alpha = parentLayer.getOpacity();
if (alpha < 0)
alpha = 0;
glColor4f(1.0f, 1.0f, 1.0f, alpha); //Set alpha to parent layer's alpha
parentTileSet.getTexture().bind(); //Bind texture
float bx = parentTileSet.getTileWidth() / 2; //Half the width
float by = parentTileSet.getTileHeight() / 2; //Half the height
float x = getX(), y = getY();
float z = 0f;
glPushMatrix(); //Save the current view matrix
glTranslatef(x, y, 0f); //Translate to the tile's position
glRotatef(rotate, 0f, 0f, 1f); //Rotate the tile if it has a rotation
if ((flipType & 1) > 0) //Are we flipping horizontally?
glScalef(-1f, 1f, 1f);
if ((flipType & 2) > 0) //Are we flipping vertically?
glScalef(1f, -1f, 1f);
//Draw the tile
glBegin(GL_QUADS);
glTexCoord2f(tex_cords.bottom_left.x, tex_cords.bottom_left.y); //bottom left
glVertex3f(-bx, -by, z);
glTexCoord2f(tex_cords.bottom_right.x, tex_cords.bottom_right.y); //bottom right
glVertex3f(bx, -by, z);
glTexCoord2f(tex_cords.top_right.x, tex_cords.top_right.y); //top right
glVertex3f(bx, by, z);
glTexCoord2f(tex_cords.top_left.x, tex_cords.top_left.y); //top left
glVertex3f(-bx, by, z);
glEnd();
glPopMatrix(); //Reload the view matrix to original state
parentTileSet.getTexture().unbind(); //Unbind the texture
}
And the result looks like the following:
http://i.stack.imgur.com/maIXk.jpg
Which is good. However, the FPS could be better, and this especially becomes an issue when the maps become more detailed. (The FPS drops to about 20).
My Ideal Solution:
Since the tiles will never change position or animate, if I render all the tiles to a texture once, and just draw that texture, then performance will increase!
So, I made a framebuffer using the following class:
public class Framebuffer implements Drawable {
private int fID, tID;
protected int width, height;
public Framebuffer(int width, int height) {
this.width = width;
this.height = height;
}
public void generate() {
fID = glGenFramebuffers();
tID = glGenTextures();
glBindFramebuffer(GL_FRAMEBUFFER, fID);
glBindTexture(GL_TEXTURE_2D, tID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_INT, (ByteBuffer) null);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tID, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
throw new RuntimeException("Framebuffer configuration error.");
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
public void begin() {
glPushMatrix();
glPushAttrib(GL_VIEWPORT_BIT);
glBindFramebuffer(GL_FRAMEBUFFER, fID);
glViewport(0, 0, width, height);
}
public void end() {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glPopMatrix();
glPopAttrib();
}
#Override
public void render() {
float x = 0f;
float y = 0f;
float z = 0f;
float bx = (this.width)/2f;
float by = (this.height)/2f;
glPushMatrix();
glBindTexture(GL_TEXTURE_2D, tID);
glBegin(GL_QUADS);
glTexCoord2f(0f, 0f); //bottom left
glVertex3f(x - bx, y - by, z);
glTexCoord2f(1f, 0f); //bottom right
glVertex3f(x + bx, y - by, z);
glTexCoord2f(1f, 1f); //top right
glVertex3f(x + bx, y + by, z);
glTexCoord2f(0f, 1f); //top left
glVertex3f(x - bx, y + by, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, 0);
glPopMatrix();
}
And then use the following code to generate the framebuffer, and render the tiles to the texture:
System.out.println("Attempting to generate frame buffer..");
try {
Framebuffer frame = new Framebuffer(tiledData.getPixelWidth(), tiledData.getPixelHeight());
frame.generate();
frame.begin();
glScalef(0.5f, 0.5f, 1f); //The game is scaled up by 2, so I'm just unscalling here.
Iterator<Drawable> drawableIterator = getSortedDrawables();
while (drawableIterator.hasNext()) {
Drawable d = drawableIterator.next();
if (d instanceof TileObject) {
TileObject t = (TileObject)d;
if (t.isGroundLayer() && !t.isParallaxLayer() && !t.isAnimated()) {
t.render(); //This render method is the one from above
drawableIterator.remove();
}
}
}
frame.end();
System.out.println("Success!");
addDrawable(frame);
} catch (RuntimeException e) {
System.out.println("Framebuffers are not supported!");
}
However, the output is this:
http://puu.sh/8Eemy.jpg
Which is not what I expected to happen. I tried scaling it, moving it, and all sorts of things but I can never get it exactly right.
My Question
What am I doing wrong? Is there another way to go about this? Am I missing something?
UPDATE
Thanks to the comments, I've got it to render correctly!
I changed the framebuffer class to be the following:
private int fID, tID;
protected int width, height;
public Framebuffer(int width, int height) {
this.width = width;
this.height = height;
}
public void generate() {
fID = glGenFramebuffers();
tID = glGenTextures();
glBindFramebuffer(GL_FRAMEBUFFER, fID);
glBindTexture(GL_TEXTURE_2D, tID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_INT, (ByteBuffer) null);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tID, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
throw new RuntimeException("Framebuffer configuration error.");
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
public void begin() {
glBindFramebuffer(GL_FRAMEBUFFER, fID);
glPushAttrib(GL_VIEWPORT_BIT);
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0, width, 0, height, -1, 1);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
}
public void end() {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glPopAttrib();
}
#Override
public void render() {
float x = this.width / 2f;
float y = this.height / 2f;
float z = 0f;
float bx = (this.width)/2f;
float by = (this.height)/2f;
glPushMatrix();
glBindTexture(GL_TEXTURE_2D, tID);
glBegin(GL_QUADS);
glTexCoord2f(0f, 0f); //bottom left
glVertex3f(x - bx, y - by, z);
glTexCoord2f(1f, 0f); //bottom right
glVertex3f(x + bx, y - by, z);
glTexCoord2f(1f, 1f); //top right
glVertex3f(x + bx, y + by, z);
glTexCoord2f(0f, 1f); //top left
glVertex3f(x - bx, y + by, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, 0);
glPopMatrix();
}
The points of interest here is the begin() and end() method, where I setup a new projection matrix and save the old one, then restore it in the end() method.
I am doing something with JOGL libraries (forced to) and I can't figure out how to offset the center zero coordinates. I would like to offset them to the bottom of my viewport, in the method
public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height)
but I can't google any way to translate int height into any meaningfull offset float coordinates.
edit:
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL_PROJECTION);
gl.glLoadIdentity();
glu.gluPerspective(45.0, width / (float) height, 0.1, 100.0);
gl.glMatrixMode(GL_MODELVIEW);
gl.glLoadIdentity();
Solved using
glu.gluLookAt(0, 0, 1, 0, 0.42, 0, 0, 1, 0);
Didn't realize the offset wasn't relative.