p5.js实现故宫橘猫赏秋图动画

用p5.js实现一个小动画――故宫橘猫赏秋图

互动媒体第二次作业要求我们手绘一幅动画，再用代码实现出动画。由于时间原因，手绘并没有画动画，而是以插画的形式画了一张，然后p5实现了动画。

这里先放效果图：

板绘插图

码绘效果图

这里强烈建议直接运行代码！！！gif丢帧！！！可怜我的渐变啊啊啊啊！！！

下面附上完整代码：

var Width=600;
var Height=700;
var pixel=1;

var Y_AXIS = 1;
var X_AXIS = 2;

var skyHeight=190;
var wall_Width=600;
var wall_Height=300;
var wuyan_width=120;
var wuyan_height=20;
var quad_width=70;
var quad_height=30;
var center_x=500;
var center_y=115;
var cat_scale=111;

var easing=1;

var Time;

//face_color=color(180,180,150,0.5*255);
function setup() {
createCanvas(Width,Height);
}

function draw() {

frameRate(5);
drawwall();
drawsky();
push();
translate(10,-5);
YinxingTree();
pop();

draw_wallshadow();

if(center_x<-10)
center_x=650;
center_x-=15*easing;
drawcat(cat_scale,center_x,center_y);

translate(10,-25);
noStroke();
fill(30);
rect(Width-10,0,200,Height);

push();
YinxingTree();
pop();

}

function drawcat(cat_scale,center_x,center_y)
{
stroke(200,200,240);
noStroke();
//肚子
pos1_x=center_x-(cat_scale)/3;
pos1_y=center_y+(cat_scale)*2/5-5;

pos2_x=center_x+(cat_scale*1/3);
pos2_y=center_y+(cat_scale)*2/5;

//前体
pos3_x=pos1_x-(cat_scale/5);
pos3_y=center_y+(cat_scale)*2/5;

pos4_x=pos1_x-(cat_scale/8);
pos4_y=center_y+(cat_scale)/15;

pos5_x=pos4_x-(cat_scale/8);
pos5_y=pos4_y-(cat_scale)/20;

//头
pos6_x=pos5_x-(cat_scale/4);
pos6_y=pos5_y-(cat_scale)/6;

pos7_x=pos5_x-(cat_scale/6);
pos7_y=pos5_y-(cat_scale)/30;

pos8_x=pos5_x-(cat_scale)*3/8;
pos8_y=pos5_y+(cat_scale)/8;

pos9_x=pos8_x+(cat_scale)/5;
pos9_y=pos8_y+(cat_scale)/5;

//屁股
pos10_x=pos2_x-(cat_scale/4)*0;
pos10_y=pos2_y-(cat_scale)*1/3;

pos11_x=pos10_x+(cat_scale*1/8);
pos11_y=pos10_y+(cat_scale)/10;

fill(220,200,180);

triangle(center_x,center_y,pos1_x,pos1_y,pos2_x,pos2_y);
triangle(center_x,center_y,pos1_x,pos1_y,pos3_x,pos3_y);
fill(150,70,10);
triangle(center_x,center_y,pos3_x,pos3_y,pos4_x,pos4_y);
triangle(pos3_x,pos3_y,pos4_x,pos4_y,pos5_x,pos5_y);
triangle(pos3_x,pos3_y,pos5_x,pos5_y,pos6_x,pos6_y);

fill(150,70,10);
triangle(pos3_x,pos3_y,pos7_x,pos7_y,pos8_x,pos8_y);
fill(180,100,10);
triangle(pos8_x,pos8_y,pos9_x,pos9_y,pos5_x,pos5_y);

fill(150,70,10);
triangle(center_x,center_y,pos2_x,pos2_y,pos10_x,pos10_y);
triangle(pos2_x,pos2_y,pos10_x,pos10_y,pos11_x,pos11_y);

fill(180);
feetControl(pos1_x-6,pos1_y);
feetControl(pos2_x-4,pos2_y);

noFill();
weiba(pos11_x,pos11_y);
}

function weiba(x,y)
{
push();
strokeWeight(10);
stroke(150,70,10);
x1=x-20;
y1=y;

x2=x+20;
y2=y-20;

x3=x+25;
y3=y+5;

x4=x+55;
y4=y-20;

bezier(x1,y1,x2,y2,x3,y3,x4,y4);
noStroke();
pop();
}
function feetControl(x,y)
{

if(x%2==0)
{
rect(x-(cat_scale)/10,y-8,(cat_scale)/10,(cat_scale)*1/3+8);
}
else
{
quad(x,y-10,
x-(cat_scale)/10,y-10,
x-(cat_scale)/10+(cat_scale/10),y+(cat_scale)*1/3,
x+(cat_scale/10),y+(cat_scale)*1/3);

quad(x,y-15,
x-(cat_scale)/10,y-15,
x-(cat_scale)/10-(cat_scale/5),y+(cat_scale)*1/3,
x-(cat_scale/5),y+(cat_scale)*1/3);
}
}

function segment(trans_x, trans_y, a,segLength) {
push();
translate(trans_x, trans_y);
rotate(a);
rect();
pop();
}

function draw_wallshadow()
{
noStroke();
var c1=color(160,10,0);
var c2=color(80,10,80);
setGradient(0,600,Width,150,c1,c2,1);

noStroke();
fill(160,10,0);
for(var i=0;i<Width;i++)
{
arc(i,600,50,15,PI,0);
i=i+80;
}
}

function drawwall()
{
noStroke();
fill(100,10,0);
rect(0, 0, Width, Height);

fill(190,70,20);
rect(0, Height-wall_Height, wall_Width, wall_Height);

drawWuYan1();
drawWuYan2();
drawWuYan3();
drawWuYan4();
}

function drawWuYan1()
{
stroke(20);
fill(190,100,10);
for(var i=0;i<Width;i++)
{
rect(i-5,wall_Height+70,wuyan_width,wuyan_height);
i=i+wuyan_width;
}
}

function drawWuYan2()
{
var cwu2_1=color(50,120,30);
var cwu2_2=color(60,10,0);

for(var j=0;j<Width+80;j++)
{
setGradient(j-65,wall_Height+35,
wuyan_width,wuyan_height+10,
cwu2_1,cwu2_2,1);
stroke(180,130,20);
rect(j-65,wall_Height+36,
wuyan_width,wuyan_height+10);
j=j+wuyan_width;
}

var cwu3_1=color(10,20,10);
var cwu3_2=color(80,100,20);
fill(50,120,30);
setGradient(0,wall_Height-15,
Width,50,cwu3_1,cwu3_2,1);
}

function drawWuYan3()
{
noStroke();
fill(190,150,90);
for(var k=0;k<Width;k++)
{
rect(k,skyHeight,wuyan_width,10);
k=k+wuyan_width;
}

fill(190,100,10);
rect(0,skyHeight+15,Width,12);
fill(190,110,30);
rect(0,skyHeight+35,Width,35);
}

function drawPIdwon(x_trans)
{
stroke(90,50,50);
push();
translate(x_trans, skyHeight+100);
rotate(0.0);
fill(140,100,50);
arc(0, 0, quad_width, quad_width-15, 0, PI);
pop();
}

function drawPIdwon_shadow(x_trans,shadow)
{
noStroke();
push();
translate(x_trans, skyHeight+100);
rotate(0.0);
fill(10,20,10);
arc(0, 0, quad_width+shadow, quad_width+shadow, 0, PI);
pop();
}

function drawquad(i,j,x_trans)
{
var c1=color(90,50,50);
var c2=color(180,90,50);
setGradient(x_trans-(quad_width/2)+i,
skyHeight+93-j,
quad_width,5,c1,c2,2);
}
function drawCicle(x_trans,angle,c1,c2,c3,i)
{
push();
noStroke();
fill(c1,c2,c3);
translate(x_trans-i+7,skyHeight+70+i*3);
rotate(angle);
arc(0,0,50,50, 0, PI/2);
pop();
}

function drawCicle_all(x_trans)
{
for(var i=0;i<8;i++)
{
drawCicle(x_trans+quad_width-8,24.5,100,10,10,i);
drawCicle(x_trans+quad_width-8,-2.2,130,110,90,i);
drawCicle(x_trans+quad_width-8,1,70,20,10,i);
drawCicle(x_trans+quad_width-8,-3.5,200,160,80,i);
}
stroke(50,10,10);
fill(140,100,50);
ellipse(x_trans+60,skyHeight+95,50,50);
fill(80,60,20);
ellipse(x_trans+60,skyHeight+95,35,35);
}

function drawWuYan4()
{
for(var x_trans=50;x_trans<Width;x_trans++)
{
drawPIdwon_shadow(x_trans+10,10);
drawPIdwon(x_trans);
for(var i=0;i<5;i++)
{
yp=i*5;
drawquad(i,yp,x_trans);
}
drawCicle_all(x_trans);
x_trans=x_trans+120;
}

}
function YinxingTree()
{
push();
drawtree(220,180,0,-20,20,random(0.6));
drawtree(120,60,0,-100,100,random(0.01));
drawtree(120,60,0,-50,160,random(0.01));
drawtree(180,160,0,40,160,random(0.05));
drawtree(200,100,0,-20,100,random(1));
drawtree(200,160,0,0,120,random(0.5));
drawtree(220,160,0,55,160,random(0.1));
drawtree(240,200,0,50,100,random(0.3));
drawtree(240,200,0,50,180,random(0.3));
drawtree(240,200,0,80,190,random(1));
drawtree(220,180,0,-50,80,random(0.1));
translate(150,90);
drawtree(220,180,0,-50,150,random(0.5));
translate(-100,-150);
drawtree(240,200,120,-100,100,random(0.01));
pop();
}

function drawtree(c1,c2,c3,pos_x,pos_y,pos_angle)
{
push();
rotate(pos_angle);
var trans_x;
var trans_y;
var trans_angle;

fill(c1,c2,c3);
for(var i=0;i<20;i++)
{
trans_x=random(50);
trans_y=random(20);
trans_angle=random(-0.5);
push();
translate(trans_x,trans_y);
rotate(trans_angle);
drawYinXing(pos_x,pos_y);
pop();
}
pop();

}

function drawYinXing(pos_x,pos_y)
{
stroke(200,150,60);
push();
translate(pos_x, pos_y);
rotate(0.0);
arc(0, 0, 30, 30, 0, PI/2);
pop();
}
function drawsky()
{
var c1 = color(90,150,205);
var c2 = color(190,200,220);
noStroke();
setGradient(0, 0, Width, skyHeight,c1,c2,1);
}

function setGradient(x, y, w, h, c1, c2,axis)
{
noFill();
if (axis == Y_AXIS) { // Top to bottom gradient
for (var i = y; i <= y+h; i++) {
var inter = map(i, y, y+h, 0, 1);
var c = lerpColor(c1, c2, inter);
stroke(c);
line(x, i, x+w, i);
}
}
else if (axis == X_AXIS) { // Left to right gradient
for (var k = x; k <= x+w; k++) {
var interk = map(k, x, x+w, 0, 1);
var ck = lerpColor(c1, c2, interk);
stroke(ck);
line(k, y, k, y+h);
}
}
}

代码结构解析

1.背景：

其实画背景还挺简单的，基本物体就是红墙，屋檐，银杏树，天空。
天空是渐变的，用了一个函数，p5官网里面也有：

function drawsky()
{
var c1 = color(90,150,205);
var c2 = color(190,200,220);
noStroke();
setGradient(0, 0, Width, skyHeight,c1,c2,1);
}

function setGradient(x, y, w, h, c1, c2,axis)
{
noFill();
if (axis == Y_AXIS) { // Top to bottom gradient
for (var i = y; i <= y+h; i++) {
var inter = map(i, y, y+h, 0, 1);
var c = lerpColor(c1, c2, inter);
stroke(c);
line(x, i, x+w, i);
}
}
else if (axis == X_AXIS) { // Left to right gradient
for (var k = x; k <= x+w; k++) {
var interk = map(k, x, x+w, 0, 1);
var ck = lerpColor(c1, c2, interk);
stroke(ck);
line(k, y, k, y+h);
}
}
}

红墙就不细说了，直接看屋檐，屋檐还稍微有点东西。观察故宫屋檐结构之后发现，故宫这样的建筑简直太有规律可循了！你只要生成一个基本元，接下来的就只用循环生成就可以。我们主要来看看圆木那一块怎么实现。
圆木那里其实还挺麻烦，主要是有光的影响，圆木被分为三个面：受光面，反光面，阴影面，直接用一个圆肯定解决不了，我想了一个办法，用三个扇形就可以区分三个面。

具体代码：

function drawCicle(x_trans,angle,c1,c2,c3,i)
{
push();
noStroke();
fill(c1,c2,c3);
translate(x_trans-i+7,skyHeight+70+i*3);
rotate(angle);
arc(0,0,50,50, 0, PI/2);
pop();
}

function drawCicle_all(x_trans)
{
for(var i=0;i<8;i++)
{
drawCicle(x_trans+quad_width-8,24.5,100,10,10,i);
drawCicle(x_trans+quad_width-8,-2.2,130,110,90,i);
drawCicle(x_trans+quad_width-8,1,70,20,10,i);
drawCicle(x_trans+quad_width-8,-3.5,200,160,80,i);
}
stroke(50,10,10);
fill(140,100,50);
ellipse(x_trans+60,skyHeight+95,50,50);
fill(80,60,20);
ellipse(x_trans+60,skyHeight+95,35,35);
}

还有瓦片上的阴影，也用了渐变过渡，这里就不贴代码了。

银杏树

一开始对银杏树没什么头绪，观察了好几棵学校里的银杏，在大风刮过之时，金黄树叶在风中颤抖摇晃，我突然有了灵感――色块堆积。我可以不用准准确确的画出这棵树长啥样，我只需要保证它在运动中是符合这棵树的逻辑的，那么这棵树就是成功的。

下面贴上代码：

function YinxingTree()
{
push();
drawtree(220,180,0,-20,20,random(0.6));
drawtree(120,60,0,-100,100,random(0.01));
drawtree(120,60,0,-50,160,random(0.01));
drawtree(180,160,0,40,160,random(0.05));
drawtree(200,100,0,-20,100,random(1));
drawtree(200,160,0,0,120,random(0.5));
drawtree(220,160,0,55,160,random(0.1));
drawtree(240,200,0,50,100,random(0.3));
drawtree(240,200,0,50,180,random(0.3));
drawtree(240,200,0,80,190,random(1));
drawtree(220,180,0,-50,80,random(0.1));
translate(150,90);
drawtree(220,180,0,-50,150,random(0.5));
translate(-100,-150);
drawtree(240,200,120,-100,100,random(0.01));
pop();
}

function drawtree(c1,c2,c3,pos_x,pos_y,pos_angle)
{
push();
rotate(pos_angle);
var trans_x;
var trans_y;
var trans_angle;

fill(c1,c2,c3);
for(var i=0;i<20;i++)
{
trans_x=random(50);
trans_y=random(20);
trans_angle=random(-0.5);
push();
translate(trans_x,trans_y);
rotate(trans_angle);
drawYinXing(pos_x,pos_y);
pop();
}
pop();

}

function drawYinXing(pos_x,pos_y)
{
stroke(200,150,60);
push();
translate(pos_x, pos_y);
rotate(0.0);
arc(0, 0, 30, 30, 0, PI/2);
pop();
}

大量使用radom可以让这棵树更自然。

2.动画主角――猫

这里我先对猫进行了一些处理――低多边形处理。
吸取了第一个实验的教训，这次我先设置了一个中心点，然后在根据这个点扩充出有关猫的肢干总共12个点，然后画三角形，形成一个没有四肢，没有尾巴的橘猫。

尾巴用了贝塞尔曲线，坐标也跟中心点关联。

猫的四肢是运动视觉的关键！！！动画之所以能动是因为有承上启下的连续性动作。猫行走从侧面看过去就是两腿相互交叉变换。所以在写动画逻辑之前你需要先画出关键帧状态。
关键帧状态确定了就可开始着手动画逻辑：首先视觉上我们先要营造出猫在原地踏步的感觉。我们有两个关键帧状态，所以可以运用模运算，在运动的中心坐标基础上模2，结果对应两个状态。

附上代码：

function feetControl(x,y)
{

if(x%2==0)
{
rect(x-(cat_scale)/10,y-8,(cat_scale)/10,(cat_scale)*1/3+8);
}
else
{
quad(x,y-10,
x-(cat_scale)/10,y-10,
x-(cat_scale)/10+(cat_scale/10),y+(cat_scale)*1/3,
x+(cat_scale/10),y+(cat_scale)*1/3);

quad(x,y-15,
x-(cat_scale)/10,y-15,
x-(cat_scale)/10-(cat_scale/5),y+(cat_scale)*1/3,
x-(cat_scale/5),y+(cat_scale)*1/3);
}
}

至此，动画完成。

手绘与码绘的对比

在动画这个应用上，其实两者各有千秋。手绘能做到画面更加精致有更多细节，更能体现质感，但同时，它又太过费时。而码绘在运动这一方面有着得天独厚的优势，它能更平滑的完成动画操作。

发现的问题

码绘在建立场景的过程中，发现对于环境色这一概念，几乎还是一个空白领域。

以上就是本文的全部内容，希望对大家的学习有所帮助

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