background problems

Programming Questions

killgannon

in Programming Questions • 1 year ago

I wasn't sure whether to post this in the other topic I made earlier but as it's a different problem I decided to make a new one. The problem I'm having is that when the animation moves the previous one is still there until the background is redrawn making it look like it has a clone following it, I solved this by drawing a new background each time the key is pressed to move the animation however when this happens it draws over the stars that are scrolling in the background making them disappear for a split second and causing them to flash. How can I get round this so that the stars are permanent and there is no clone following the animation?

Star [] starCollection = new Star [200];
Animation aniFly, aniTurnL, aniTurnR;
float xpos = 500;
float ypos = 500;
void setup() {
size(1000,600);
frameRate(60);
aniFly = new Animation("sprite_shipm2_fly",4);
aniTurnL = new Animation("sprite_shipm2_turnL", 3);
aniTurnR = new Animation("sprite_shipm2_turnR", 3);
for (int i = 0; i < 200; i++) {
float sX = random (200, 800);
float sY = random (600);
float sZ = random (2, 8);
starCollection[i] = new Star (sX, sY, sZ);
}
}
void draw() {
background (0);
for (int j = 0; j < 200; j++) {
starCollection [j].run();
}
fill(185, 81, 138);
rect (0, 0, 200, 600);
rect (800, 0, 200, 600);
aniFly.display(xpos, ypos);
print(xpos);
}
void keyPressed() {
if (key == CODED) {
if (keyCode == LEFT) {
background(0);
fill(185, 81, 138);
rect (0, 0, 200, 600);
rect (800, 0, 200, 600);
aniTurnL.display(xpos, ypos);
xpos -= 5;
if (xpos <= 237) {
xpos = 237;
}
} else if (keyCode == RIGHT) {
background(0);
fill(185, 81, 138);
rect (0, 0, 200, 600);
rect (800, 0, 200, 600);
aniTurnR.display(xpos, ypos);
xpos += 5;
if (xpos >= 765) {
xpos = 765;
}
}
}
}
class Animation {
PImage[] images;
int imageCount;
int frame;
Animation(String imagePrefix, int count) {
imageCount = count;
images = new PImage[imageCount];
for (int i = 0; i < imageCount; i++) {
// Use nf() to number format 'i' into four digits
String filename = imagePrefix + nf(i, 4) + ".gif";
images[i] = loadImage(filename);
}
}
void display(float xpos, float ypos) {
frame = (frame+1) % imageCount;
imageMode(CENTER);
image(images[frame], xpos, ypos);
}
}
class Star {
float x = 0;
float y = 0;
float z = 0;
float speed = 2.5;
Star (float _x, float _y, float _z) {
x = _x;
y = _y;
z = _z;
}
void run() {
display();
movement();
}
void display() {
noStroke();
fill (255);
ellipse (x, y, z, z);
}
void movement() {
y += speed;
if (y > 600) {
y = random (-30, 0);
}
}
}

Replies(6)

calsign

Re: background problems

1 year ago

Without the background() call, I don't notice the graphics problem that you describe; however, I am using rectangles in place of your images...

If you're doing everything correctly, you shouldn't need to call background() more than once (at the beginning) every frame.

Also, I think your logic may be flawed - ideally, you update the objects before you display them, although I can't stare at your code for too long right now...

killgannon

Re: background problems

1 year ago

sorry, upon closer inspection its not how I described, the problem is that the animation is switching rapidly between the two animations when the key is held down.

I've uploaded it to openprocessing http://www.openprocessing.org/sketch/60167

when the right arrow key is held down the flickering occurs, its present on the left arrow key too but not as bad, any ideas?

calsign

Re: background problems

1 year ago

If I understand your intention correctly, you want to display the right-angled image when the right mouse button is pressed and the left-angled image when the left mouse button is pressed.

I think that if (when you display the animation) you simply pick which image to display based on what key is pressed (or if one is pressed at all), then that will solve your problems...

killgannon

Re: background problems

1 year ago

nah, I have three animations which are a ship flying, turning left and turning right as a default the flying animation plays and when either the right arrow key or the left arrow key are pressed the animation changes to the appropriate turning animation but what appears to be happening, mostly with the right arrow for some reason, is that when the key is held down it flickers quickly back and forth between the right turning and the flying animations which isn't what I want it to do, I want it to be a continuous animation as the key is held down.

calsign

Re: background problems

1 year ago

Again, try reading what the key state is when you draw the image.

I think the variables are causing difficulties in the way that you are using them; but before we sort that out, we have to make sure that the animation changes work in isolation... Besides, why create those variables if they aren't necessary?

PhiLho

Re: background problems

1 year ago

" I wasn't sure whether to post this in the other topic I made earlier but as it's a different problem I decided to make a new one."
It is OK, except you also posted in the old thread and I answered there... You can make a new thread, but you should avoid duplicate messages.

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