Processing 创建运动的物体
1、编程实现物体从左到右的平滑移动
输入代码：
int radius = 40;
float x = -radius;
float speed = 0.5;
void setup() {
size(240, 120);
smooth();
ellipseMode(RADIUS);
}
void draw() {
background(0);
x += speed; // Increase the value of x
arc(x, 60, radius, radius, 0.52, 5.76);
}
2、物体的循环运动
输入代码：
int radius = 40;
float x = -radius;
float speed = 0.5;
void setup() {
size(240, 120);
smooth();
ellipseMode(RADIUS);
}
void draw() {
background(0);
x += speed;
if (x > width+radius) {
x = -radius;
}
arc(x, 60, radius, radius, 0.52, 5.76);
}
注意这里使用了 if 判断语句，就是判断是否超出了设置的窗口，如果超出窗口，就重新设置物体的坐标，再次从起点开始运动；窗口坐标示意如下图所示：
3、碰到墙壁就翻转，并朝相反的方向移动
输入代码：
int radius = 40;
float x = 110;
float speed = 0.5;
int direction = 1;
void setup() {
size(240, 120);
smooth();
ellipseMode(RADIUS);
}
void draw() {
background(0);
x += speed * direction;
if ((x > width-radius) || (x < radius)) {
direction = -direction; // Flip direction
}
if (direction == 1) {
arc(x, 60, radius, radius, 0.52, 5.76); // Face right
} else {
arc(x, 60, radius, radius, 3.67, 8.9); // Face left
}
}
4、从屏幕上一个像素点移动到另一个像素点
输入代码：
int startX = 20; // Initial x-coordinate
int stopX = 160; // Final x-coordinate
int startY = 30; // Initial y-coordinate
int stopY = 80; // Final y-coordinate
float x = startX; // Current x-coordinate
float y = startY; // Current y-coordinate
float step = 0.005; // Size of each step (0.0 to 1.0)
float pct = 0.0; // Percentage traveled (0.0 to 1.0)
void setup() {
size(240, 120);
smooth();
}
void draw() {
background(0);
if (pct < 1.0) {
x = startX + ((stopX-startX) * pct);
y = startY + ((stopY-startX) * pct);
pct += step;
}
ellipse(x, y, 20, 20);
}
5、产生随机图形
输入代码：
void setup() {
size(240, 120);
smooth();
}
void draw() {
background(204);
for (int x = 20; x < width; x += 20) {
float mx = mouseX / 10;
float offsetA = random(-mx, mx);
float offsetB = random(-mx, mx);
line(x + offsetA, 20, x - offsetB, 100);
}
}
6、让物体随机移动到任意位置
输入代码：
float speed = 2.5;
int diameter = 20;
float x;
float y;
void setup() {
size(240, 120);
smooth();
x = width/2;
y = height/2;
}
void draw() {
x += random(-speed, speed);
y += random(-speed, speed);
ellipse(x, y, diameter, diameter);
}
7、控制物体的运动时间
输入代码：
int time1 = 2000;
int time2 = 4000;
float x = 0;
void setup() {
size(480, 120);
smooth();
}
void draw() {
int currentTime = millis();
background(204);
if (currentTime > time2) {
x -= 0.5;
} else if (currentTime > time1) {
x += 2;
}
ellipse(x, 60, 90, 90);
}
