Trying to make a smoother oscillation.

Programming Questions

atezun

Trying to make a smoother oscillation.

in Programming Questions • 2 years ago

I have a day/night cycle in my sketch that sets the overall ambient light within a looping animation based on the postion of the sun and moon within the sky by setting the alpha of a rectangle that covers the width and height of the sketch. My day cycle works perfectly fine because the alpha ranges between 0 and 220, but my night cycle only ranges between 190 and 220 and looks choppier which I suspect has to do with the way i calculate the alpha value.

void ambient_light_cycle() {
//Calculates the position of the current day/night cycle;
float light_position = angle % TWO_PI;
float light_alpha = 220;
//Sun starts on horizon and peaks at HALF_PI
//Moon enters horizon at PI and peaks PI + HALF_PI
if(light_position <= HALF_PI) {
light_alpha = 220 - ((220/HALF_PI) * (light_position % HALF_PI));
} else if (light_position <= PI && light_position > HALF_PI) {
light_alpha = (220/HALF_PI) * (light_position % HALF_PI);
} else if(light_position > PI && light_position <= (PI + HALF_PI)) {
light_alpha = 220 - ((30/HALF_PI) * (light_position % HALF_PI));
} else if(light_position > (PI + HALF_PI) && light_position <= TWO_PI) {
light_alpha = 190 + ((30/HALF_PI) * (light_position % HALF_PI));
}
fill(0, light_alpha);
rect(0,0,width,height);
}

Suggestions?

Replies(2)

tfguy44

Re: Trying to make a smoother oscillation.

2 years ago

The sun and mood are directly opposite each other, correct?

So the sun is setting as the moon is rising, and the moon is setting as the sun is rising?

So your cycles is:

Sun rise, moon set -> high noon, no moon -> Sun setting, moon rise -> no sun, high moon -> repeat

And the values you want:

220 -> 0 -> 220 -> 190 -> repeat

This can be accomplished like so:

float light_position = angle % TWO_PI;

if( light_position < PI ){ // Sun in sky.

result = map(abs(-HALF_PI + light_position), 0, HALF_PI, 0, 220);

} else {
result = map(abs(-HALF_PI + light_position - PI), 0, HALF_PI, 190, 220);

}

Try it... This code is untested!

atezun

Re: Trying to make a smoother oscillation.

2 years ago

I changed the value2 upper and lower bounds of the the night cycle to 190 and 220 but other than that it works perfect. Thanks!

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