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Added ear clipping triangulation. Added a tiny vertex type to the library to facilitate the change.

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This commit is contained in:
Richard Fabian
2017-11-11 22:37:52 +00:00
parent b434c2497f
commit 5896933508
1 changed files with 146 additions and 48 deletions
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162
tiny_obj_loader.h
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@@ -108,6 +108,14 @@ typedef double real_t;
typedef float real_t;
#endif
struct V3 { real_t x,y,z; };
inline V3 operator+(const V3 &l,const V3 &r){V3 o;o.x=l.x+r.x;o.y=l.y+r.y;o.z=l.z+r.z;return o;}
inline V3 operator-(const V3 &l,const V3 &r){V3 o;o.x=l.x-r.x;o.y=l.y-r.y;o.z=l.z-r.z;return o;}
inline V3 operator*(const V3 &l,real_t r){V3 o;o.x=l.x*r;o.y=l.y*r;o.z=l.z*r;return o;}
inline V3 cross(const V3 &l,const V3 &r){V3 o;o.x=l.y*r.z-r.y*l.z;o.y=l.z*r.x-r.z*l.x;o.z=l.x*r.y-r.x*l.y;return o;}
inline real_t dot(const V3 &l,const V3 &r){return l.x*r.x+l.y*r.y+l.z*r.z;}
struct V2 { real_t x,y; };
typedef enum {
TEXTURE_TYPE_NONE, // default
TEXTURE_TYPE_SPHERE,
@@ -228,9 +236,9 @@ typedef struct {
// Vertex attributes
typedef struct {
std::vector<real_t> vertices; // 'v'
std::vector<real_t> normals; // 'vn'
std::vector<real_t> texcoords; // 'vt'
std::vector<V3> vertices; // 'v'
std::vector<V3> normals; // 'vn'
std::vector<V2> texcoords; // 'vt'
std::vector<real_t> colors; // extension: vertex colors
} attrib_t;
@@ -974,7 +982,7 @@ static void InitMaterial(material_t *material) {
static bool exportFaceGroupToShape(
shape_t *shape, const std::vector<std::vector<vertex_index> > &faceGroup,
const std::vector<tag_t> &tags, const int material_id,
const std::string &name, bool triangulate) {
const std::string &name, bool triangulate, const std::vector<V3> &v ) {
if (faceGroup.empty()) {
return false;
}
@@ -990,11 +998,72 @@ static bool exportFaceGroupToShape(
size_t npolys = face.size();
if (triangulate) {
// Polygon -> triangle fan conversion
for (size_t k = 2; k < npolys; k++) {
i1 = i2;
i2 = face[k];
V3 face_normal = {0,0,0};
for(size_t k = 0; k < npolys; ++k) {
int vi0 = face[(k+0)%npolys].v_idx;
int vi1 = face[(k+1)%npolys].v_idx;
int vi2 = face[(k+2)%npolys].v_idx;
const V3 &v0 = v[vi0];
const V3 &v1 = v[vi1];
const V3 &v2 = v[vi2];
const V3 e0 = v1 - v0;
const V3 e1 = v2 - v1;
const V3 n = cross( e0, e1 );
face_normal = face_normal + n;
}
// face_normal is currently area of face
{
real_t l = sqrt(dot( face_normal, face_normal ));
face_normal = face_normal * (1.0/l);
}
int maxRounds = 10; // arbitrary max loop count to protect against unexpected errors
std::vector<vertex_index> remainingFace = face;
size_t guess_vert = 0;
while( remainingFace.size() > 3 && maxRounds > 0 ) {
npolys = remainingFace.size();
if( guess_vert >= npolys ) {
maxRounds -= 1;
guess_vert -= npolys;
}
i0 = remainingFace[(guess_vert+0)%npolys];
i1 = remainingFace[(guess_vert+1)%npolys];
i2 = remainingFace[(guess_vert+2)%npolys];
int vi0 = i0.v_idx;
int vi1 = i1.v_idx;
int vi2 = i2.v_idx;
const V3 &v0 = v[vi0];
const V3 &v1 = v[vi1];
const V3 &v2 = v[vi2];
const V3 e0 = v1 - v0;
const V3 e1 = v2 - v1;
const V3 n = cross( e0, e1 );
bool internal = dot( n, face_normal ) < 0.0f;
if( internal ) { guess_vert += 1; continue; }
// check all other verts in case they are inside this triangle
bool overlap = false;
for( size_t otherVert = 3; otherVert < npolys; ++otherVert ) {
int ovi = remainingFace[(guess_vert+otherVert)%npolys].v_idx;
const V3 &ov = v[ovi];
if( dot( face_normal, cross( e0, ov-v0 ) ) < 0 )
continue;
if( dot( face_normal, cross( e1, ov-v1 ) ) < 0 )
continue;
if( dot( face_normal, cross( v0-v2, ov-v2 ) ) < 0 )
continue;
// vert inside triangle
overlap = true;
break;
}
if( overlap ) { guess_vert += 1; continue; }
// this triangle is an ear
{
index_t idx0, idx1, idx2;
idx0.vertex_index = i0.v_idx;
idx0.normal_index = i0.vn_idx;
@@ -1013,6 +1082,40 @@ static bool exportFaceGroupToShape(
shape->mesh.num_face_vertices.push_back(3);
shape->mesh.material_ids.push_back(material_id);
}
// remove v1 from the list
size_t removed_vert_index = (guess_vert+1)%npolys;
while( removed_vert_index + 1 < npolys ) {
remainingFace[removed_vert_index] = remainingFace[removed_vert_index+1];
removed_vert_index += 1;
}
remainingFace.pop_back();
}
if( remainingFace.size() == 3 ) {
i0 = remainingFace[0];
i1 = remainingFace[1];
i2 = remainingFace[2];
{
index_t idx0, idx1, idx2;
idx0.vertex_index = i0.v_idx;
idx0.normal_index = i0.vn_idx;
idx0.texcoord_index = i0.vt_idx;
idx1.vertex_index = i1.v_idx;
idx1.normal_index = i1.vn_idx;
idx1.texcoord_index = i1.vt_idx;
idx2.vertex_index = i2.v_idx;
idx2.normal_index = i2.vn_idx;
idx2.texcoord_index = i2.vt_idx;
shape->mesh.indices.push_back(idx0);
shape->mesh.indices.push_back(idx1);
shape->mesh.indices.push_back(idx2);
shape->mesh.num_face_vertices.push_back(3);
shape->mesh.material_ids.push_back(material_id);
}
}
} else {
for (size_t k = 0; k < npolys; k++) {
index_t idx;
@@ -1528,9 +1631,9 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
bool triangulate) {
std::stringstream errss;
std::vector<real_t> v;
std::vector<real_t> vn;
std::vector<real_t> vt;
std::vector<V3> v;
std::vector<V3> vn;
std::vector<V2> vt;
std::vector<real_t> vc;
std::vector<tag_t> tags;
std::vector<std::vector<vertex_index> > faceGroup;
@@ -1573,12 +1676,10 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
// vertex
if (token[0] == 'v' && IS_SPACE((token[1]))) {
token += 2;
real_t x, y, z;
V3 v3;
real_t r, g, b;
parseVertexWithColor(&x, &y, &z, &r, &g, &b, &token);
v.push_back(x);
v.push_back(y);
v.push_back(z);
parseVertexWithColor(&v3.x, &v3.y, &v3.z, &r, &g, &b, &token);
v.push_back(v3);
vc.push_back(r);
vc.push_back(g);
@@ -1589,21 +1690,18 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
// normal
if (token[0] == 'v' && token[1] == 'n' && IS_SPACE((token[2]))) {
token += 3;
real_t x, y, z;
parseReal3(&x, &y, &z, &token);
vn.push_back(x);
vn.push_back(y);
vn.push_back(z);
V3 v3;
parseReal3(&v3.x, &v3.y, &v3.z, &token);
vn.push_back(v3);
continue;
}
// texcoord
if (token[0] == 'v' && token[1] == 't' && IS_SPACE((token[2]))) {
token += 3;
real_t x, y;
parseReal2(&x, &y, &token);
vt.push_back(x);
vt.push_back(y);
V2 v2;
parseReal2(&v2.x, &v2.y, &token);
vt.push_back(v2);
continue;
}
@@ -1617,9 +1715,9 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
while (!IS_NEW_LINE(token[0])) {
vertex_index vi;
if (!parseTriple(&token, static_cast<int>(v.size() / 3),
static_cast<int>(vn.size() / 3),
static_cast<int>(vt.size() / 2), &vi)) {
if (!parseTriple(&token, static_cast<int>(v.size()),
static_cast<int>(vn.size()),
static_cast<int>(vt.size()), &vi)) {
if (err) {
(*err) = "Failed parse `f' line(e.g. zero value for face index).\n";
}
@@ -1657,7 +1755,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
// this time.
// just clear `faceGroup` after `exportFaceGroupToShape()` call.
exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
triangulate);
triangulate, v);
faceGroup.clear();
material = newMaterialId;
}
@@ -1712,7 +1810,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
if (token[0] == 'g' && IS_SPACE((token[1]))) {
// flush previous face group.
bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
triangulate);
triangulate, v);
(void)ret; // return value not used.
if (shape.mesh.indices.size() > 0) {
@@ -1749,7 +1847,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
if (token[0] == 'o' && IS_SPACE((token[1]))) {
// flush previous face group.
bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
triangulate);
triangulate, v);
if (ret) {
shapes->push_back(shape);
}
@@ -1799,7 +1897,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
}
bool ret = exportFaceGroupToShape(&shape, faceGroup, tags, material, name,
triangulate);
triangulate, v);
// exportFaceGroupToShape return false when `usemtl` is called in the last
// line.
// we also add `shape` to `shapes` when `shape.mesh` has already some