1. Problem description:
as shown in the following figure, what are the specific values of the parameters u and v in this surface parameter equation? for example, when drawing a sphere, u and v represent radians, so which two angles do they represent?
Source of the Echarts chart: spherical surface drawn by Echarts-gl
reference Code:
parametricEquation: {
u: {
min: -Math.PI,
max: Math.PI,
step: Math.PI / 20
},
v: {
min: 0,
max: Math.PI,
step: Math.PI / 20
},
x: function (u, v) {
return Math.sin(v) * Math.sin(u);
},
y: function (u, v) {
return Math.sin(v) * Math.cos(u);
},
z: function (u, v) {
return Math.cos(v);
}
}ps: I checked the echarts document, the document is not very clear about this piece, I hope friends who are familiar with echarts-gl can explain it.