我正在修改一个arcball类,使其在每次调用rollforward()时旋转1度。我阅读代码有困难,但我认为我需要编写一个替代xy\u to\u sphere()的方法,其中;设点1=v1,点2=v2,这样
pi/180 = (v1.x * v2.x + v1.y * v2.y + v1.z * v2.z) / (abs(v1.x) * abs(v2.x) + abs(v1.y) * abs(v2.y) + abs(v1.z) * abs(v2.z))
<-更新编辑->
我试着简单地添加一个Angular ((sin(pi/180)*半径)转换成y轴(在前滚()中)
v_drag = XY_to_sphere(center_x, center_y - ((sin(PI/180) * radius))/2);
在100次滚动后,它会偏离几度(这可能是浮点舍入错误,我会尝试找到它,但我必须学习一些东西)
(新问题)当它达到完全旋转时,它消失了大约1度,我不知道为什么。
我不确定我最初的想法,上面的解决方案是否会更好
现在我要尝试设置它,使它复位后,它达到360度,以规避浮点错误和我消失的错误
</-更新编辑->
弧球类
// Ariel and V3ga's arcball class with a couple tiny mods by Robert Hodgin
class Arcball {
float center_x, center_y, radius;
Vec3 v_down, v_drag;
Quat q_now, q_down, q_drag;
Vec3[] axisSet;
int axis;
float mxv, myv;
float x, y;
Arcball(float center_x, float center_y, float radius){
this.center_x = center_x;
this.center_y = center_y;
this.radius = radius;
v_down = new Vec3();
v_drag = new Vec3();
q_now = new Quat();
q_down = new Quat();
q_drag = new Quat();
axisSet = new Vec3[] {new Vec3(1.0f, 0.0f, 0.0f), new Vec3(0.0f, 1.0f, 0.0f), new Vec3(0.0f, 0.0f, 1.0f)};
axis = -1; // no constraints...
}
void rollforward(){
q_down.set(q_now);
v_down = XY_to_sphere(center_x, center_y);
q_down.set(q_now);
q_drag.reset();
v_drag = XY_to_sphere(center_x, center_y - 1);
q_drag.set(Vec3.dot(v_down, v_drag), Vec3.cross(v_down, v_drag));
}
/*
void mousePressed(){
v_down = XY_to_sphere(mouseX, mouseY);
q_down.set(q_now);
q_drag.reset();
}
void mouseDragged(){
v_drag = XY_to_sphere(mouseX, mouseY);
q_drag.set(Vec3.dot(v_down, v_drag), Vec3.cross(v_down, v_drag));
}
* /
void run(){
q_now = Quat.mul(q_drag, q_down);
applyQuat2Matrix(q_now);
x += mxv;
y += myv;
mxv -= mxv * .01;
myv -= myv * .01;
}
Vec3 XY_to_sphere(float x, float y){
Vec3 v = new Vec3();
v.x = (x - center_x) / radius;
v.y = (y - center_y) / radius;
float mag = v.x * v.x + v.y * v.y;
if (mag > 1.0f){
v.normalize();
} else {
v.z = sqrt(1.0f - mag);
}
return (axis == -1) ? v : constrain_vector(v, axisSet[axis]);
}
Vec3 constrain_vector(Vec3 vector, Vec3 axis){
Vec3 res = new Vec3();
res.sub(vector, Vec3.mul(axis, Vec3.dot(axis, vector)));
res.normalize();
return res;
}
void applyQuat2Matrix(Quat q){
// instead of transforming q into a matrix and applying it...
float[] aa = q.getValue();
rotate(aa[0], aa[1], aa[2], aa[3]);
}
}
static class Vec3{
float x, y, z;
Vec3(){
}
Vec3(float x, float y, float z){
this.x = x;
this.y = y;
this.z = z;
}
void normalize(){
float length = length();
x /= length;
y /= length;
z /= length;
}
float length(){
return (float) Math.sqrt(x * x + y * y + z * z);
}
static Vec3 cross(Vec3 v1, Vec3 v2){
Vec3 res = new Vec3();
res.x = v1.y * v2.z - v1.z * v2.y;
res.y = v1.z * v2.x - v1.x * v2.z;
res.z = v1.x * v2.y - v1.y * v2.x;
return res;
}
static float dot(Vec3 v1, Vec3 v2){
return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z; // cos(1) = (v1.x * v2.x + v1.y * v2.y + v1.z * v2.z) / (abs(v1.x) * abs(v2.x) + abs(v1.y) * abs(v2.y) + abs(v1.z) * abs(v2.z))
}
static Vec3 mul(Vec3 v, float d){
Vec3 res = new Vec3();
res.x = v.x * d;
res.y = v.y * d;
res.z = v.z * d;
return res;
}
void sub(Vec3 v1, Vec3 v2){
x = v1.x - v2.x;
y = v1.y - v2.y;
z = v1.z - v2.z;
}
}
static class Quat{
float w, x, y, z;
Quat(){
reset();
}
Quat(float w, float x, float y, float z){
this.w = w;
this.x = x;
this.y = y;
this.z = z;
}
void reset(){
w = 1.0f;
x = 0.0f;
y = 0.0f;
z = 0.0f;
}
void set(float w, Vec3 v){
this.w = w;
x = v.x;
y = v.y;
z = v.z;
}
void set(Quat q){
w = q.w;
x = q.x;
y = q.y;
z = q.z;
}
static Quat mul(Quat q1, Quat q2){
Quat res = new Quat();
res.w = q1.w * q2.w - q1.x * q2.x - q1.y * q2.y - q1.z * q2.z;
res.x = q1.w * q2.x + q1.x * q2.w + q1.y * q2.z - q1.z * q2.y;
res.y = q1.w * q2.y + q1.y * q2.w + q1.z * q2.x - q1.x * q2.z;
res.z = q1.w * q2.z + q1.z * q2.w + q1.x * q2.y - q1.y * q2.x;
return res;
}
float[] getValue(){
// transforming this quat into an angle and an axis vector...
float[] res = new float[4];
float sa = (float) Math.sqrt(1.0f - w * w);
if (sa < EPSILON){
sa = 1.0f;
}
res[0] = (float) Math.acos(w) * 2.0f;
res[1] = x / sa;
res[2] = y / sa;
res[3] = z / sa;
return res;
}
}
我的代码,使用w键滚动立方体//arcball=newarcball(width/2,height/21115);非常接近于每个弧球1度;
Arcball arcball;
//framecount
int fcount, lastm;
float frate;
int fint = 3;
//int test_count = 0;
boolean[] keys = new boolean[13];
final int w = 0;
final int s = 1;
final int a = 2;
final int d = 3;
final int q = 4;
final int e = 5;
final int r = 6;
final int f = 7;
final int z = 8;
final int x = 9;
final int t = 10;
final int g = 11;
final int m = 12;
boolean fullscreen = false;
int aa = 8; //2,4,8
void settings() {
size(900, 700, P3D);
screensizex = 900;
screensizey = 700;
}
smooth(aa);
}
void setup() {
frameRate(60);
noStroke();
keys[m] = false;
arcball = new Arcball(width/2, height/2, 115);
}
void draw() {
lights();
background(255,160,122);
if(keys[w]) {
arcball.rollforward();
// test_count = test_count + 1;
// print(" " + test_count); // needs to be 360 at 1 full rotation
}
translate(width/2, height/2-100, 0);
box(50);
translate(0, 200, 0);
arcball.run();
box(50);
}
void keyPressed() {
switch(key) {
case 97:
keys[a] = true;
break;
case 100:
keys[d] = true;
break;
case 101:
keys[e] = true;
break;
case 102:
keys[f] = true;
break;
case 103:
keys[g] = true;
break;
case 109:
if(keys[m] == true) keys[m] = false;
else keys[m] = true;
break;
case 113:
keys[q] = true;
break;
case 114:
keys[r] = true;
break;
case 115:
keys[s] = true;
break;
case 116:
keys[t] = true;
break;
case 119:
keys[w] = true;
break;
case 120:
keys[x] = true;
break;
case 122:
keys[z] = true;
break;
}
}
暂无答案!
目前还没有任何答案,快来回答吧!