I’m trying to animate a quad in 2D space that has a texture applied to it, but its as if its not clearing (glClear is DEFINITELY being called before each render) or maybe its making a new quad each time, I don’t know.
anyway, instead of a moving square, I get this:
here is my run() method:
private void run() {
isRunning = true;
int frames = 0;
long frameCounter = 0;
final double frameTime = 1.0 / FRAME_CAP;
long lastTime = Time.getTime();
double unprocessedTime = 0;
while (isRunning) {
boolean render = false;
long startTime = Time.getTime();
long passedTime = startTime - lastTime;
lastTime = startTime;
unprocessedTime += passedTime / (double) Time.SECOND;
frameCounter += passedTime;
while (unprocessedTime > frameTime) {
render = true;
unprocessedTime -= frameTime;
if (Window.isCloseRequested()) {
stop();
}
Time.setDelta(frameTime);
Input.update();
game.input(); // IMPORTANT
game.update(); // IMPORTANT
if (frameCounter >= Time.SECOND) {
System.out.println(frames);
frames = 0;
frameCounter = 0;
}
}
if (render) {
render(); // IMPORTANT
frames++;
} else {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
cleanUp();
}
here is my RenderUtil class, which contains static methods such as clearScreen() and initGraphics():
public static void clearScreen(){
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER); //Although it is 2D, I might want to add some depth later on ;)
}
public static void initGraphics(int WIDTH, int HEIGHT){
glClearColor(1.0f, 0.0f, 0.0f, 0.0f);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, WIDTH, 0, HEIGHT, 1, -1);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_TEXTURE_2D);
}
public static String getOpenGLVersion(){
return glGetString(GL_VERSION);
}
and here is what I do in render():
private void render() {
clearScreen();
game.render();
Window.render(); // quite simply, Display.update();
}
this is a part of my Game class
public void render(){
sprite.render();
}
public void update(){
if (Input.getKey(Input.KEY_A)){
sprite.setPos(sprite.getPos().getX() - 0.25f, sprite.getPos().getY());
}
if (Input.getKey(Input.KEY_D)){
sprite.setPos(sprite.getPos().getX() + 0.25f, sprite.getPos().getY());
}
if (Input.getKey(Input.KEY_S)){
sprite.setPos(sprite.getPos().getX(), sprite.getPos().getY() - 0.25f);
}
if (Input.getKey(Input.KEY_W)){
sprite.setPos(sprite.getPos().getX(), sprite.getPos().getY() + 0.25f);
}
And crucially, the actual rendering, the Sprite class.
private Vector2f pos;
private int size;
//which animation the sprite has
private int i;
private int j;
private Texture texture;
public Sprite(String name, int size){
i = 0;
j = 0;
this.size = size;
pos = new Vector2f(0,0);
try{
texture = TextureLoader.getTexture("PNG", new FileInputStream(new File("res/" + name + ".png")));
} catch (IOException e){
e.printStackTrace();
}
}
public void render(){
//IMPORTANT
//should I be doing glBegin --coordinate stuff-- glEnd every render()?
texture.bind();
glBegin(GL_QUADS);
// this is just a bit of square math to determine which tile of a spritesheet the quad should display.
//BL
glTexCoord2f(i * 0.25f, (j+1) * 0.25f);
// glTexCoord2f(0, 1); of the tile
glVertex2f(pos.getX(), pos.getY());
//BR
glTexCoord2f((i+1) * 0.25f, (j+1) * 0.25f);
// glTexCoord2f(1,1); of the tile
glVertex2f(pos.getX() + size, pos.getY());
//TR
glTexCoord2f((i+1) * 0.25f, j * 0.25f);
// glTexCoord2f(1,0); of the tile
glVertex2f(pos.getX() + size, pos.getY() + size);
//TL
glTexCoord2f(i * 0.25f, j * 0.25f);
// glTexCoord2f(0,0); of the tile
glVertex2f(pos.getX(), pos.getY() + size);
glEnd();
}
public Vector2f getPos(){
return pos;
}
public void setPos(Vector2f r){
pos = r;
}
public void setPos(float x, float y){
pos.setX(x);
pos.setY(y);
}
public int getI() {
return i;
}
public void setI(int i) {
this.i = i;
}
public int getJ() {
return j;
}
public void setJ(int j) {
this.j = j;
}
so when rendering my “sprite” should I be doing glBegin --coordinates-- glEnd every render cycle? Does this create an entirely new quad as well as the old one? that’s the only possible problem that I can see.
