Skewed Vertices with Quaternions, Matrices, and Good Ol' Trig
Post: #1
I am getting a problem with my dynamic animated models where vertices are skewed when a rotation is performed. Translation works fine but that's no good if I can't also rotate the joints. I tried a matrix, a quaternion, and a normal rotation function, but nothing works.
The Good
The C++ (The Bad)
and The C (and The Ugly)
The Good
Code:
struct Matrix4x4{
float m[16];
void loadIdentity(){
glPushMatrix();
glLoadIdentity();
glGetFloatv(GL_MODELVIEW_MATRIX,m);
glPopMatrix();
}
Matrix4x4(){
this->loadIdentity();
}
inline void set(oeVec3& move,oeVec3& rot){
glPushMatrix();
glLoadIdentity();
glTranslatef(move.x,move.y,move.z);
glRotatef(rot.x,1,0,0);
glRotatef(rot.y,0,1,0);
glRotatef(rot.z,0,0,1);
glGetFloatv(GL_MODELVIEW_MATRIX,m);
glPopMatrix();
}
inline oeVec3& operator *(oeVec3& v){
//printf("Doing Dot Product with an oeVec3\n");
/*v.x=v.x*this->m[0]+v.y*this->m[4]+v.z*this->m[8]+this->m[12];
v.y=v.x*this->m[1]+v.y*this->m[5]+v.z*this->m[9]+this->m[13];
v.z=v.x*this->m[2]+v.y*this->m[6]+v.z*this->m[10]+this->m[14];*/
/*v.x=v.x*this->m[0]+v.y*this->m[1]+v.z*this->m[2]+this->m[4];
v.y=v.x*this->m[5]+v.y*this->m[6]+v.z*this->m[7]+this->m[8];
v.z=v.x*this->m[9]+v.y*this->m[10]+v.z*this->m[11]+this->m[12];*/
return v;
}
inline void print(){
// for(int i=0;i<16;i++) printf("m[%i]=%f\n",i,m[i]);
printf("%f\n",this->m[12]);
printf("%f\n",this->m[13]);
printf("%f\n",this->m[14]);
}
};The C++ (The Bad)
Code:
namespace Model{
struct Vertex:oeVec3{
unsigned int b;
};
struct Bone:oeVec3{
oeVec3 rot;
int p;
inline Bone& rotate(float x,float y,float z){
OERotate((oeVec3*)this,x,y,z);
this->rot.x=x;
this->rot.y=y;
this->rot.z=z;
return *this;
}
inline void move(float x,float y,float z){
this->x+=x;
this->y+=y;
this->z+=z;
}
inline void print(){
printf("%f %f %f\n",x,y,z);
}
};
struct CompiledBone:oeOrientation{
//Matrix4x4 m;
OEQuat rotation;
inline void compile(){
//OEQuatRotate(rotation,rot.x,1,0,0);
float sineValue=sinf( rot.y / 1.0f * (M_PI/ 180.0f));
rotation.x=0*sineValue;
rotation.y=1*sineValue;
rotation.z=0*sineValue;
rotation.w=cosf(rot.y / 2.0f * (M_PI/ 180.));
float m=rotation.x*rotation.x+rotation.y*rotation.y+rotation.z*rotation.z+rotation.w*rotation.w;
rotation.w/=m;
rotation.x/=m;
rotation.y/=m;
rotation.z/=m;
//OEQuatRotate(this->rotation, this->rot.y , 0, 1, 0);
//OEQuatRotate(rotation,rot.z,0,0,1);
//OEQuatRotateX(rotation,rot.x*toDegrees);
//OEQuatRotateY(rotation,rot.y*toDegrees);
//OEQuatRotateZ(rotation,rot.z*toDegrees);
}
inline void transformVec3(oeVec3& v){
//OEQuatRotateVec3(v,rotation,v);
oeVec3 old=v;
/*OEQuat tempq={-rotation.x,-rotation.y,-rotation.z,rotation.w};
OEQuat temp={v.x,v.y,v.z,0};
OEQuatMultiplyByVec3(temp,rotation,temp);
OEQuatMultiplyByVec3(temp,temp,tempq);
v.x=x+temp.x+old.x;
v.y=y+temp.y+old.y;
v.z=z+temp.z+old.z;*/
}
};
struct DynamicModel{
struct{unsigned int v,f,b;}count;
Vertex* v;
oeVec2* t;
oeVec3* n;
oeFace* f;
Bone* b;
oeVec3* cmpv;
CompiledBone* cmpb;//cached for speed
unsigned int displayList;
virtual void oldLoad(char* filename){
oeMesh* m=oeLoadObjFile(filename);
printf("Attemping to load %s\n",filename);
this->count.v=m->count.v;
this->count.f=m->count.f;
this->v=new Vertex[m->count.v];
this->f=new oeFace[m->count.f];
this->t=new oeVec2[m->count.v];
this->n=new oeVec3[m->count.v];
this->cmpv=new oeVec3[m->count.v];
FILE* file=fopen(filename,"r");
this->count.b=0;
unsigned int cv,cb,boneID;
int boneIDs[20];
boneIDs[0]=-1;
cv=cb=0;
boneID=0;
char line[512];
//unsigned int bcount=0;
if(file==NULL){
printf("Failed to open %s\n",filename);
exit(1);
}
while(!feof(file)){
fgets(line,255,file);
if((line[0]=='b')&&(line[1]==' ')&&strlen(line)-1>strlen("b 0\n")) this->count.b++;
}
rewind(file);
this->b=new Bone[this->count.b];
if(this->b==NULL){
printf("Couldn't allocate %i bones for file named %s\n",this->count.b,filename);
exit(2);
}
float x,y,z;
while(!feof(file)){
fgets(line,255,file);
if(sscanf(line,"b %f %f %f",&x,&y,&z)==3){
this->b[cb].x=x;
this->b[cb].y=y;
this->b[cb].z=z;
this->b[cb].p=boneIDs[boneID];
boneID++;
boneIDs[boneID]=cb;
cb++;
}
else if(sscanf(line,"b %f",&x)==1){if(x==0)boneID--;}
if(3==sscanf(line,"v %f %f %f",&x,&y,&z)){
this->v[cv].x=m->v[cv].x;
this->v[cv].y=m->v[cv].y;
this->v[cv].z=m->v[cv].z;
this->v[cv].b=boneIDs[boneID];
cv++;
}
}
if(this->count.b!=cb){
printf("Could only find %i of %i bones in %s\n",cb,this->count.b,filename);
printf("Found %i of %i verts\n",cv,this->count.v);
exit(1);
}
oeMeshDelete(m);
}
virtual void load(char* filename){
int fcount,vcount,ncount,tcount;
unsigned int cv,cf,ct,cn,v[3],n[3],t[3];
char buffer[256];
float x,y,z;
char line[1000];
cv=cf=ct=cn=fcount=vcount=ncount=tcount=0;
FILE* file=fopen(filename,"r");
this->count.b=0;
unsigned int cb,boneID;
int boneIDs[20];
boneIDs[0]=-1;
cb=0;
boneID=0;
if(file==NULL){
printf("Failed to open %s\n",filename);
// return NULL;
exit(1);
}
while(!feof(file)){
fgets(buffer,255,file);
if((buffer[0]=='v')&&(buffer[1]==' ')){
vcount++;
}
else if((buffer[0]=='f')&&(buffer[1]==' ')){
fcount++;
}
else if((buffer[0]=='v')&&(buffer[1]=='n')){
ncount++;
}
else if((buffer[0]=='v')&&(buffer[1]=='t')){
tcount++;
}
if((buffer[0]=='b')&&(buffer[1]==' ')&&strlen(buffer)-1>strlen("b 0\n")) this->count.b++;
}
rewind(file);
this->v=new Vertex[vcount];
this->f=new oeFace[fcount];
this->t=new oeVec2[tcount];
this->n=new oeVec3[ncount];
this->cmpv=new oeVec3[vcount];
this->b=new Bone[this->count.b];
if(this->b==NULL){
printf("Couldn't allocate %i bones for file named %s\n",this->count.b,filename);
exit(2);
}
if(this->f==NULL){
printf("Couldn't allocate %i faces for file named %s\n",fcount,filename);
exit(2);
}
if(this->v==NULL){
printf("Couldn't allocate %i vertices for file named %s\n",vcount,filename);
exit(2);
}
if(this->n==NULL){
printf("Couldn't allocate %i normals for file named %s\n",ncount,filename);
exit(2);
}
if(this->t==NULL){
printf("Couldn't allocate %i uv's for file named %s\n",tcount,filename);
exit(2);
}
while(!feof(file)){
fgets(buffer,255,file);
if(3==sscanf(buffer,"b %f %f %f",&x,&y,&z)){
this->b[cb].x=x;
this->b[cb].y=y;
this->b[cb].z=z;
//printf("b boneIDs[boneID]:%i position: %f %f %f ",boneIDs[boneID],x,y,z);
this->b[cb].p=boneIDs[boneID];
//printf("this->b[cb].p: %i ",this->b[cb].p);
//printf("boneID:%i ",boneID);
boneID++;
//printf("boneID:%i ",boneID);
boneIDs[boneID]=cb;
//printf("boneIDs[boneID]:%i \n",boneIDs[boneID]);
cb++;
fflush(stdout);
}
else if(sscanf(buffer,"b %f",&x)==1){
//if(x==0) boneID--;
}
else if(3==sscanf(buffer,"v %f %f %f",&x,&y,&z)){
this->v[cv].x=this->cmpv[cv].x=x;
this->v[cv].y=this->cmpv[cv].y=y;
this->v[cv].z=this->cmpv[cv].z=z;
this->v[cv].b=boneIDs[boneID];
cv++;
}
else if(2==sscanf(buffer,"vt %f %f",&x,&y)){
this->t[ct].x=x;
this->t[ct].y=y;
ct++;
}
else if(3==sscanf(buffer,"vn %f %f %f",&x,&y,&z)){
this->n[cn].x=x;
this->n[cn].y=y;
this->n[cn].z=z;
cn++;
}
else if(9==sscanf(buffer,"f %i/%i/%i %i/%i/%i %i/%i/%i",&v[0],&t[0],&n[0],&v[1],&t[1],&n[1],&v[2],&t[2],&n[2])){
if(v[0]<1||v[1]<1||v[2]<1){
printf("Invalid vertex id in file %s\n",filename);
exit(1);
}
this->f[cf].v[0]=v[0]-1;
this->f[cf].v[1]=v[1]-1;
this->f[cf].v[2]=v[2]-1;
this->f[cf].t[0]=t[0]-1;
this->f[cf].t[1]=t[1]-1;
this->f[cf].t[2]=t[2]-1;
this->f[cf].n[0]=n[0]-1;
this->f[cf].n[1]=n[1]-1;
this->f[cf].n[2]=n[2]-1;
cf++;
}
else if(6==sscanf(buffer,"f %d//%d %d//%d %d//%d",&v[0],&n[0],&v[1],&n[1],&v[2],&n[2])){
if(v[0]<1||v[1]<1||v[2]<1){
printf("Invalid vertex id in file %s\n",filename);
exit(1);
}
this->f[cf].v[0]=v[0]-1;
this->f[cf].v[1]=v[1]-1;
this->f[cf].v[2]=v[2]-1;
this->f[cf].n[0]=n[0]-1;
this->f[cf].n[1]=n[1]-1;
this->f[cf].n[2]=n[2]-1;
cf++;
}
else if(3==sscanf(buffer,"f %d %d %d",&v[0],&v[1],&v[2])){
if(v[0]<1||v[1]<1||v[2]<1){
printf("Invalid vertex id in file %s\n",filename);
exit(1);
}
this->f[cf].v[0]=v[0]-1;
this->f[cf].v[1]=v[1]-1;
this->f[cf].v[2]=v[2]-1;
cf++;
}
}
if(cf==fcount&&cv==vcount&&ct==tcount&&cn==vcount){
this->count.f=fcount;
this->count.v=vcount;
}else{
printf("\nError loading %s\nFound|Stated to be\n",filename);
printf("Vertex:%d|%d\n",cv,vcount);
printf("Face:%d|%d\n",cf,fcount);
printf("TexCoord:%d|%d\n",ct,tcount);
printf("Normals:%d|%d\n",cn,ncount);
exit(1);
}
if(this->count.b!=cb){
printf("Could only find %i of %i bones in %s\n",cb,this->count.b,filename);
printf("Found %i of %i verts\n",cv,this->count.v);
exit(1);
}
fclose(file);
this->cmpb=new CompiledBone[this->count.b];
}
inline void draw(){
oeVec3* v;oeFace* f;oeVec3* n;oeVec2* t;
glBegin(GL_TRIANGLES);
for(int cf=0; cf<this->count.f; cf++){
f=&this->f[cf];
for (int cv = 0; cv <3; cv++) {
v=&this->cmpv[this->f[cf].v[cv]];
t=&this->t[this->f[cf].t[cv]];
n=&this->n[this->f[cf].n[cv]];
glNormal3f(n->x,n->y,n->z);
glTexCoord2f(t->x,t->y);
glVertex3f(v->x,v->y,v->z);
}
}
glEnd();
// OEDebugOnlyLine(printf("In %s, line #%i:%s\n",__FILE__,__LINE__,gluErrorString(glGetError())));
}
inline void drawWithNonCompiledVs(){
oeVec3* v;oeFace* f;oeVec3* n;oeVec2* t;
glBegin(GL_TRIANGLES);
for(int cf=0; cf<this->count.f; cf++){
f=&this->f[cf];
for (int cv = 0; cv <3; cv++) {
v=&this->v[this->f[cf].v[cv]];
t=&this->t[this->f[cf].t[cv]];
n=&this->n[this->f[cf].n[cv]];
glNormal3f(n->x,n->y,n->z);
glTexCoord2f(t->x,t->y);
glVertex3f(v->x,v->y,v->z);
//printf("v = %f %f %f\n",v->x,v->y,v->z);
}
}
glEnd();
// OEDebugOnlyLine(printf("In %s, line #%i:%s\n",__FILE__,__LINE__,gluErrorString(glGetError())));
}
inline Bone& bone(int ID){
return b[ID];
}
virtual void flush(){
memset((void*)cmpb,0,sizeof(CompiledBone)*this->count.b);
for(int i=0;i<this->count.b;i++){
if(i==0){//for that special case where 0 gets skipped
cmpb[i].x=b->x;
cmpb[i].y=b->y;
cmpb[i].z=b->z;
cmpb[i].rot.x=b->rot.x;
cmpb[i].rot.y=b->rot.y;
cmpb[i].rot.z=b->rot.z;
}
else{
Bone* b=&this->b[i];
while(b->p!=-1){
cmpb[i].x+=b->x;
cmpb[i].y+=b->y;
cmpb[i].z+=b->z;
cmpb[i].rot.x+=b->rot.x;
cmpb[i].rot.y+=b->rot.y;
cmpb[i].rot.z+=b->rot.z;
b=&this->b[b->p];
}
}
cmpb[i].compile();
}
for(int j=0;j<this->count.v;j++){
this->cmpv[j]=this->v[j];
cmpb[this->v[j].b].transformVec3(this->cmpv[j]);
/*cv.x=this->b[v.b].x+v.x;
cv.y=this->b[v.b].y+v.y;
cv.z=this->b[v.b].z+v.z;*/
}
}
virtual void release(){
delete[] this->v;
delete[] this->cmpv;
delete[] this->f;
delete[] this->t;
delete[] this->n;
delete[] this->b;
delete[] this->cmpb;
}
};
}and The C (and The Ugly)
Code:
#define OEAdd(a,b) {a.x+b.x,a.y+b.y,a.z+b.z}
#define OESub(a,b) {a.x-b.x,a.y-b.y,a.z-b.z}
#define OEMul(a,b) {a.x*b.x,a.y*b.y,a.z*b.z}
#define OEDiv(a,b) {a.x/b.x,a.y/b.y,a.z/b.z}
#define OEDot(a,b) {a.x*b.x+a.y*b.y+a.z*b.z}
#define OEQuatMultiply(q,a,b) \
({q.x=a.w*b.x + a.x*b.w + a.y*b.z - a.z*b.y;\
q.y=a.w*b.y - a.x*b.z + a.y*b.w + a.z*b.x;\
q.z=a.w*b.z + a.x*b.y - a.y*b.x + a.z*b.w;\
q.w=a.w*b.w - a.x*b.x - a.y*b.y - a.z*b.z;})
#define OEQuatMultiplyByVec3(q,a,b) \
({q.x=a.w*b.x + a.y*b.z - a.z*b.y;\
q.y=a.w*b.y - a.x*b.z + a.z*b.x;\
q.z=a.w*b.z + a.x*b.y - a.y*b.x;})
#define OEQuatConjungate(q) ({q.x=-q.x; q.y=-q.y; q.z=-q.z;})
#define OEQuatRotateVec3(r,q,v) \
({\
OEQuat tempq={-q.x,-q.y,-q.z,q.w};\
OEQuat temp={v.x,v.y,v.z,0};\
OEQuatMultiplyByVec3(temp,q,temp);\
OEQuatMultiplyByVec3(temp,temp,tempq);\
/*return*/ r=temp;r;\
})
#define OEQuatRotate(q,angle,x,y,z)\
({\
float sineValue=sinf(angle / 2.0f * (M_PI/ 180.0f));\
q.x=x*sineValue;\
q.y=y*sineValue;\
q.z=z*sineValue;\
q.w=cosf(angle / 2.0f * (M_PI/ 180.));\
})
#define OEQuatRotateX(q,angle) q.x=sinf(angle/2.0);
#define OEQuatRotateY(q,angle) q.y=sinf(angle/2.0);
#define OEQuatRotateZ(q,angle) q.z=sinf(angle/2.0);
inline void OERotate(oeVec3* p,float x,float y,float z){
//Z
p->x= p->x*cos( toRadians*z) - p->y*sin( toRadians*z);
p->y= p->x*sin( toRadians*z) + p->y*cos( toRadians*z) ;
//Y
p->x=p-> x*cos( toRadians*y) - p->z*sin( toRadians*y);
p->z= p->x*sin( toRadians*y) + p->z*cos( toRadians*y) ;
//X
p->z= p->y*cos( toRadians*x) - p->z*sin( toRadians*x);
p->y= p->y*sin( toRadians*x) + p->z*cos( toRadians*x) ;
}
Post: #3
Can't spend the time to look at it in detail at the moment, but you can compare against the reference implementations I use for matrix, vector, and quaternion math here:
http://sacredsoftware.net/tutorials/Vectors/Vector.c
http://sacredsoftware.net/tutorials/Quat...aternion.c
http://sacredsoftware.net/tutorials/Matrices/Matrix.c
http://sacredsoftware.net/tutorials/Vectors/Vector.c
http://sacredsoftware.net/tutorials/Quat...aternion.c
http://sacredsoftware.net/tutorials/Matrices/Matrix.c
Post: #4
That was a lot of code, and while I skimmed it, I didn't fuly parse it. But off the top of my head I have a guess:
When performing your matrix transforms on your model, are you (semantically) doing something like the following?
Because if you are, what you're seeing is a progressive loss of precision.
When performing your matrix transforms on your model, are you (semantically) doing something like the following?
Code:
for each vertex:
vertices[i] = matrix * vertices[i]Because if you are, what you're seeing is a progressive loss of precision.
Post: #5
No, no progressive loss of presicion, as the model makes 2 sets of vertecies, one that is write-once read-only and another that is write-only so any loss of precision is kept constant.
@ThemsAllTook: Great sample, its all in C and easy to follow, thanks.
@ThemsAllTook: Great sample, its all in C and easy to follow, thanks.
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