我在Processing中做了一些实验，我经常需要一个在两个值之间振荡的int或float，比如从0到255，然后再回到0，一次增加1个值。我经常写一些布尔切换方法来做这个，但我想知道是否有更简单的方法来做到这一点？
喜欢，有没有一种方法可以：
oscillate(0, 255, 1);
我做了上面描述的那个？
答案 0 :(得分：1)
如果您想要特定地控制振荡的完成和计算方式，那么没有什么比编写自己的函数更好的了。但是，如果您正在寻找内置的内容，请查看sin()函数，该函数是数学函数sine的实现。实际上，即使在我自己的函数中，我也使用Processing提供的sin和cos函数。只需使用函数输出乘以它在-1和1之间振荡的值即可。将它与特定数字相乘可以得到你想要的效果。然后将其转换为int将获得整数值。
可以看到此sin()功能的一个示例here。为了便于参考，此处复制了该页面的代码：
// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 13-6: Oscillation
float theta = 0.0;
void setup() {
size(200,200);
smooth();
}
void draw() {
background(255);
// The output of the sin() function oscillates smoothly between -1 and 1.
// By adding 1 we get values between 0 and 2.
// By multiplying by 100, we get values between 0 and 200 which can be used as the ellipse's x location.
float x = (sin(theta) + 1) * width/2;
// We can also use Processing's "map()" function to achieve the same results
// http://processing.org/reference/map_.html
// float x = map(sin(theta),-1,1,0,width);
// With each cycle, increment theta
theta += 0.05;
// Draw the ellipse at the value produced by sine
fill(0);
stroke(0);
line(width/2,0,x,height/2);
ellipse(x,height/2,16,16);
}
答案 1 :(得分：0)
我喜欢波浪......我认为这是一个三角波......
试试这个：
int x;
void setup(){
frameRate(6);
}
void draw(){
println(sawWave (x, 4));
x++;
}
int sawWave(int value, int max){
return (abs(abs( value% (max*2) - max) - max));
}
这里可以使用更多波浪。单击草图以转到下一个...
PGraphics [] pg = new PGraphics[4];
int w_dim = 1000;
PFont font;
ArrayList<PVector> points = new ArrayList<PVector>();
float[] f;
float x, res = 1;
String expression = "";
int expr = 0;
float valInput;
void setup() {
// golden ratio :P
size(w_dim, int(w_dim/1.6180));
smooth();
background(255);
pg[0] = createGraphics(width, height, JAVA2D);
font = loadFont("STHeitiSC-Medium-48.vlw");
//draw graph lines
pg[0].beginDraw();
pg[0].stroke(240);
pg[0].line(0, height/2, width, height/2);
pg[0].line(0, height/2 - 112, width, height/2 - 112);
pg[0].line(0, height/2 + 112, width, height/2 + 112);
pg[0].endDraw();
}
void draw() {
frame.setTitle(nf(frameRate, 2, 2));
/*XXXXXX*/
background(255);
x +=res;
float xR = radians(x);
switch (expr) {
case 0:
valInput = sin(xR);
expression = "y = sin(x)";
break;
case 1:
valInput = sin(tan(xR)*pow(sin(xR), 10));
expression = "y = sin(tan(x)*sin(x)ˆ10";
break;
case 2:
valInput = pow(sin(xR*PI), 12);
expression = "y = (sin(x*PI))ˆ12";
break;
case 3:
valInput = cos(sin(xR*3)+xR*3);
expression = "cos(sin(x*3)+x*3";
break;
case 4:
valInput = x%100/100;
expression = "(x%100/100)";
break;
case 5:
valInput = sin(tan(cos(xR)*1.2));
expression = "sin(tan(cos(x)*1.2";
break;
case 6:
valInput = cos(xR)*sin(xR);
expression = "cos(x)*sin(x)";
break;
case 7:
valInput = sin(xR)*sin(xR*1.5);
expression = "cos(x)*sin(x*1.5)";
break;
case 8:
valInput = sin(tan(xR)*0.05);
expression = "sin(tan(x)*0.05";
break;
case 9:
valInput = cos(sin(xR*3))*sin(xR*0.2);
expression = "cos(sin(x*3))*sin(x*2)";
break;
case 10:
valInput = sin(pow(8, sin(xR)));
expression = "sin(8ˆsin(x))";
break;
case 11:
valInput = sin(exp(cos(xR*0.8))*2);
expression = "sin(eˆcos(x*0.8)*2";
break;
case 12:
valInput = sin(xR-PI*tan(xR)*0.01);
expression = "sin(x-PI*tan(x)*0.01";
break;
case 13:
valInput = pow(sin(xR*PI), 12);
expression = "sin(x*PI)ˆ12";
break;
case 14:
valInput = cos(sin(xR)*tan(xR*PI)*PI/8);
expression = "cos(sin(x)*tan(x*PI)*PI/8";
break;
case 15:
valInput = cos(sin(xR*3)+xR*3);
expression = "cos(sin(x*3))+x*3";
break;
case 16:
valInput = pow(abs(sin(xR*2))*0.6, sin(xR*2))*0.5;
expression = "|(sin(x*2)*0.6)ˆsin(x*2)*0.5|";
break;
case 17:
valInput = abs(xR % (2) - 1);
expression = "|x%2-1|";
break;
case 18:
valInput = sin(xR)*tan(xR)*0.1;
expression = "sin(x)*tan(x)*0.1";
break;
case 19:
valInput = sin(tan(xR));
expression = "sin(tan(x))";
break;
case 20:
valInput = (cos(xR) * sin(xR*30) )* 0.3;
expression = "(cos(x) * sin(x*30))*0.3";
break;
case 21:
valInput = cos(xR*(xR*0.5));
expression = "cos(x*(x*0.5))";
break;
case 22:
valInput = cos(xR) * (tan(xR*0.5)*0.1);
expression = "cos(x)* tan(x*0.5)*0.1";
break;
case 23:
valInput = sqrt(abs(sin(xR)));
expression = "squareRoot(|sin(x)|)";
break;
case 24:
valInput = sqrt(abs(sin(xR)*sin(xR*2)));
expression = "squareRoot(|sin(x)*sin(x*2)|)";
break;
case 25:
valInput = sqrt(abs(sin(xR)*sin(xR*10)));
expression = "squareRoot(|sin(x)*sin(x*10)|)";
break;
case 26:
valInput = tan(sin(xR)*cos(xR*3));
expression = "tan(sin(x)*cox(x)";
break;
case 27:
valInput = sin(tan(cos(xR)));
expression = "sin(tan(cos(x))";
break;
}
//float value =
// float value =
//float value =
//float value =
//float value
//float value
//println (value);
//drawExpression(0, 0, width, height, value, "");
image(pg[0], 0, 0);
drawExpression(0, 0, width, height, valInput, x, expression);
}
void mouseReleased() {
//background(255);
pg[0].beginDraw();
pg[0].background(255);
pg[0].stroke(240);
pg[0].strokeWeight(1);
pg[0].line(0, height/2, width, height/2);
pg[0].line(0, height/2 - 112, width, height/2 - 112);
pg[0].line(0, height/2 + 112, width, height/2 + 112);
pg[0].endDraw();
x=0;
expr= (expr+1)%29;
println (expr);
}
void drawExpression (float _x, float y, float w, float h, float value_y, float value_x, String _expression)
{
float v_center = h/2;
float h_center = w/2;
float pos_x = _x + value_x;
float pos_y = (v_center + (-value_y * h/5));
// points.add(new PVector(pos_x, pos_y));
for (PVector p:points) {
//point(p.x, p.y);
}
//draw wave
pg[0].beginDraw();
pg[0].stroke(0);
pg[0].strokeWeight(2);
pg[0].point(pos_x, pos_y);
pg[0].endDraw();
//erase this area
float v_size = v_center - v_center/2;
noStroke();
fill(255, 0, 0);
rect( _x, _x, w, v_size);
float el_x = h_center + (-value_y * w/4);
float el_y = v_size / 2;
float c = map (value_y, -1, 1, 255, 0);
float s = map (value_y, -1, 1, 2, 80);
//draw pulse ellipse;
fill(c);
noStroke();
fill(240);
ellipse( w/2, el_y, s, s);
//draw horizontal ellipse
stroke(150, 200);
strokeWeight(10);
noFill();
ellipse( el_x, el_y, 40, 40);
// write value
textFont(font, 20);
fill(100);
String st_y = nfs(value_y, 3, 4);
text("y = ", h_center - textWidth("y =")-200, 438);
text(st_y, h_center - 200, 438);
String st_x = nfs( value_x, 3, 4);
float line2_x1 = h_center - textWidth("x = ") + 200 - textWidth(st_x) ;
fill(100);
text("x = ", line2_x1, 438);
text(st_x, h_center + 200 - textWidth(st_x), 438);
float line_x1 = line2_x1;
float line_y = 438;
float line2_y = 438;
float line_x2 = h_center - textWidth("y =")-200;
strokeWeight(0.5);
stroke(220);
line(line2_x1, line2_y, pos_x, pos_y);
line(pos_x, 169, pos_x, 390);
line(0, pos_y, width, pos_y);
line(line_x2, line_y, pos_x, pos_y);
stroke(200);
line(line_x1, line_y, line_x1 + textWidth("x =" + st_x) + 4, line_y);
line(h_center - textWidth("y =") - 200, line2_y, h_center - 200 + textWidth( st_y), line2_y);
stroke(80);
strokeWeight(6);
point(pos_x, pos_y);
//write expression
textSize(25);
fill(200);
noStroke();
text(_expression, width/2 - textWidth(_expression)/2, height - 10);
}
答案 2 :(得分：0)
振荡变量的最简单方法是使用处理库Ani进行动画处理。它可以简单地为特定变量定义动画的时间和END值：
aniA = new Ani(this, 1.5, "x", 255);
如果你想从255回到0你只需将模式设置为'Ani.YOYO'并设置'repeat'：
aniA.setPlayMode(Ani.YOYO);
aniA.repeat();
所以整个振荡就像这样：
import de.looksgood.ani.*;
Ani aniA;
float y = 0;
void setup() {
size(200,200);
smooth();
Ani.init(this);
aniA = new Ani(this, 1.5, "y", 200, Ani.QUAD_IN_OUT);
aniA.setPlayMode(Ani.YOYO);
aniA.repeat();
}
void draw() {
background(255);
fill(0);
stroke(0);
line(width/2,0,y,height/2);
ellipse(y,height/2,16,16);
}
您还可以针对动画here
进行特定的不同缓动