我正在学习p5.js。
在本地测试example below时，
我收到以下错误：
这是我在本地测试的代码：
let flower = (p) => {
let size, shading;
p.setup = function() {
let renderer = p.createCanvas(1024, 768, p.WEBGL);
p.noStroke();
size = p.min(p.width, p.height) / 3;
shading = new p5.Shader(renderer, p.vert, p.frag);
p.shader(shading);
p.mouseX = p.width / 2;
p.mouseY = p.height / 2;
}
p.draw = function() {
p.background("#1a0633");
p.orbitControl();
p.rotateX(p.PI / 2);
let time = p.millis() / 1000;
shading.setUniform('iTime', time);
shading.setUniform('size', size);
shading.setUniform('mouse', [p.mouseX / p.width, p.mouseY / p.height]);
p.plane(1, 1, 100, 100);
}
};
let p5Flower = new p5(flower);
是什么导致错误？
最佳答案
您尚未定义任何着色器
这个错误
提示p.vert未设置任何内容。
另外，我非常确定您要将p.shader(shading)从setup移到draw。它在示例中起作用的唯一原因是因为只有1个着色器。一旦有2，它将失败。但是，这不是为什么您会出错。由于未定义p.vert，因此出现错误。
const vert = `precision mediump float;
#define PI 3.14159265359
// our vertex data
attribute vec3 aPosition;
attribute vec2 aTexCoord;
//transform
uniform mat4 uModelViewMatrix;
uniform mat4 uProjectionMatrix;
uniform mat3 uNormalMatrix;
// lets get texcoords just for fun!
varying vec2 vTexCoord;
varying float n;
uniform float iTime;
uniform vec2 mouse;
uniform float size;
// --- Simplex3D noise by Lallis/2015 https://www.shadertoy.com/view/XtBGDG
//http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
//simplex pretty much 99% copied from there
//adjusted by getting "completely random" gradients instead of randoming from 12 preset ones
//and normalizing the gradient vector
float noise3D(vec3 p)
{
return fract(sin(dot(p ,vec3(12.9898,78.233,128.852))) * 43758.5453)*2.0-1.0;
}
float simplex3D(vec3 p)
{
float f3 = 1.0/3.0;
float s = (p.x+p.y+p.z)*f3;
int i = int(floor(p.x+s));
int j = int(floor(p.y+s));
int k = int(floor(p.z+s));
float g3 = 1.0/6.0;
float t = float((i+j+k))*g3;
float x0 = float(i)-t;
float y0 = float(j)-t;
float z0 = float(k)-t;
x0 = p.x-x0;
y0 = p.y-y0;
z0 = p.z-z0;
int i1,j1,k1;
int i2,j2,k2;
if(x0>=y0)
{
if(y0>=z0){ i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; } // X Y Z order
else if(x0>=z0){ i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; } // X Z Y order
else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; } // Z X Z order
}
else
{
if(y0<z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; } // Z Y X order
else if(x0<z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; } // Y Z X order
else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; } // Y X Z order
}
float x1 = x0 - float(i1) + g3;
float y1 = y0 - float(j1) + g3;
float z1 = z0 - float(k1) + g3;
float x2 = x0 - float(i2) + 2.0*g3;
float y2 = y0 - float(j2) + 2.0*g3;
float z2 = z0 - float(k2) + 2.0*g3;
float x3 = x0 - 1.0 + 3.0*g3;
float y3 = y0 - 1.0 + 3.0*g3;
float z3 = z0 - 1.0 + 3.0*g3;
vec3 ijk0 = vec3(i,j,k);
vec3 ijk1 = vec3(i+i1,j+j1,k+k1);
vec3 ijk2 = vec3(i+i2,j+j2,k+k2);
vec3 ijk3 = vec3(i+1,j+1,k+1);
vec3 gr0 = normalize(vec3(noise3D(ijk0),noise3D(ijk0*2.01),noise3D(ijk0*2.02)));
vec3 gr1 = normalize(vec3(noise3D(ijk1),noise3D(ijk1*2.01),noise3D(ijk1*2.02)));
vec3 gr2 = normalize(vec3(noise3D(ijk2),noise3D(ijk2*2.01),noise3D(ijk2*2.02)));
vec3 gr3 = normalize(vec3(noise3D(ijk3),noise3D(ijk3*2.01),noise3D(ijk3*2.02)));
float n0 = 0.0;
float n1 = 0.0;
float n2 = 0.0;
float n3 = 0.0;
float t0 = 0.5 - x0*x0 - y0*y0 - z0*z0;
if(t0>=0.0)
{
t0*=t0;
n0 = t0 * t0 * dot(gr0, vec3(x0, y0, z0));
}
float t1 = 0.5 - x1*x1 - y1*y1 - z1*z1;
if(t1>=0.0)
{
t1*=t1;
n1 = t1 * t1 * dot(gr1, vec3(x1, y1, z1));
}
float t2 = 0.5 - x2*x2 - y2*y2 - z2*z2;
if(t2>=0.0)
{
t2 *= t2;
n2 = t2 * t2 * dot(gr2, vec3(x2, y2, z2));
}
float t3 = 0.5 - x3*x3 - y3*y3 - z3*z3;
if(t3>=0.0)
{
t3 *= t3;
n3 = t3 * t3 * dot(gr3, vec3(x3, y3, z3));
}
return 96.0*(n0+n1+n2+n3);
}
void main() {
vTexCoord = aTexCoord;
vec4 pos = vec4(aPosition, 1.0);
n = simplex3D(vec3(iTime,pos.xy * 10.))*0.5+0.5;
vec3 temp = pos.xyz;
pos.x = cos(temp.x * PI * 10. * mouse.x) * (n+0.3) * size * (temp.y-mouse.y+0.5);
pos.z = sin(temp.x * PI * 10. * mouse.x) * (n+0.3) * size * (temp.y-mouse.y+0.5);
pos.y = pos.y * size * 3.;
gl_Position = uProjectionMatrix * uModelViewMatrix * pos;
}`
const frag = `precision mediump float;
varying vec2 vTexCoord;
varying float n;
uniform float iTime;
void main()
{
vec2 uv = vTexCoord;//*2.0-1.0;
vec3 col = vec3(n*1.0, n*n*n*0.76, .2);
gl_FragColor = vec4(col, 1.0);
}`
let flower = (p) => {
let size, shading;
p.setup = function() {
let renderer = p.createCanvas(1024, 768, p.WEBGL);
p.noStroke();
size = p.min(p.width, p.height) / 3;
shading = new p5.Shader(renderer, vert, frag);
p.mouseX = p.width / 2;
p.mouseY = p.height / 2;
}
p.draw = function() {
p.background("#1a0633");
p.orbitControl();
p.rotateX(p.PI / 2);
p.shader(shading);
let time = p.millis() / 1000;
shading.setUniform('iTime', time);
shading.setUniform('size', size);
shading.setUniform('mouse', [p.mouseX / p.width, p.mouseY / p.height]);
p.plane(1, 1, 100, 100);
}
};
let p5Flower = new p5(flower);<script src="https://cdn.jsdelivr.net/npm/[email protected]/lib/p5.js"></script>关于javascript - 使用WebGL调用p5.js的createcanvas方法时出错，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/59621329/