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Merge pull request #61558 from kleonc/triangle_mesh_from_triangle_strip

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Make `Mesh::generate_triangle_mesh()` handle `PRIMITIVE_TRIANGLE_STRIP`
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Rémi Verschelde 2022-06-07 22:07:16 +02:00 committed by GitHub
commit 60eec78a1f
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2 changed files with 47 additions and 18 deletions
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2
doc/classes/Mesh.xml
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@ -123,7 +123,7 @@
<method name="generate_triangle_mesh" qualifiers="const">
<return type="TriangleMesh" />
<description>
Generate a [TriangleMesh] from the mesh.
Generate a [TriangleMesh] from the mesh. Considers only surfaces using one of these primitive types: [constant PRIMITIVE_TRIANGLES], [constant PRIMITIVE_TRIANGLE_STRIP].
</description>
</method>
<method name="get_aabb" qualifiers="const">

63
scene/resources/mesh.cpp
View file

@ -161,32 +161,45 @@ Ref<TriangleMesh> Mesh::generate_triangle_mesh() const {
return triangle_mesh;
}
int facecount = 0;
int faces_size = 0;
for (int i = 0; i < get_surface_count(); i++) {
if (surface_get_primitive_type(i) != PRIMITIVE_TRIANGLES) {
continue;
}
if (surface_get_format(i) & ARRAY_FORMAT_INDEX) {
facecount += surface_get_array_index_len(i);
} else {
facecount += surface_get_array_len(i);
switch (surface_get_primitive_type(i)) {
case PRIMITIVE_TRIANGLES: {
int len = (surface_get_format(i) & ARRAY_FORMAT_INDEX) ? surface_get_array_index_len(i) : surface_get_array_len(i);
// Don't error if zero, it's valid (we'll just skip it later).
ERR_CONTINUE_MSG((len % 3) != 0, vformat("Ignoring surface %d, incorrect %s count: %d (for PRIMITIVE_TRIANGLES).", i, (surface_get_format(i) & ARRAY_FORMAT_INDEX) ? "index" : "vertex", len));
faces_size += len;
} break;
case PRIMITIVE_TRIANGLE_STRIP: {
int len = (surface_get_format(i) & ARRAY_FORMAT_INDEX) ? surface_get_array_index_len(i) : surface_get_array_len(i);
// Don't error if zero, it's valid (we'll just skip it later).
ERR_CONTINUE_MSG(len != 0 && len < 3, vformat("Ignoring surface %d, incorrect %s count: %d (for PRIMITIVE_TRIANGLE_STRIP).", i, (surface_get_format(i) & ARRAY_FORMAT_INDEX) ? "index" : "vertex", len));
faces_size += (len == 0) ? 0 : (len - 2) * 3;
} break;
default: {
} break;
}
}
if (facecount == 0 || (facecount % 3) != 0) {
if (faces_size == 0) {
return triangle_mesh;
}
Vector<Vector3> faces;
faces.resize(facecount);
faces.resize(faces_size);
Vector3 *facesw = faces.ptrw();
int widx = 0;
for (int i = 0; i < get_surface_count(); i++) {
if (surface_get_primitive_type(i) != PRIMITIVE_TRIANGLES) {
Mesh::PrimitiveType primitive = surface_get_primitive_type(i);
if (primitive != PRIMITIVE_TRIANGLES && primitive != PRIMITIVE_TRIANGLE_STRIP) {
continue;
}
int len = (surface_get_format(i) & ARRAY_FORMAT_INDEX) ? surface_get_array_index_len(i) : surface_get_array_len(i);
if ((primitive == PRIMITIVE_TRIANGLES && (len == 0 || (len % 3) != 0)) || (primitive == PRIMITIVE_TRIANGLE_STRIP && len < 3)) {
// Error was already shown, just skip (including zero).
continue;
}
@ -202,14 +215,30 @@ Ref<TriangleMesh> Mesh::generate_triangle_mesh() const {
Vector<int> indices = a[ARRAY_INDEX];
const int *ir = indices.ptr();
for (int j = 0; j < ic; j++) {
int index = ir[j];
facesw[widx++] = vr[index];
if (primitive == PRIMITIVE_TRIANGLES) {
for (int j = 0; j < ic; j++) {
int index = ir[j];
facesw[widx++] = vr[index];
}
} else { // PRIMITIVE_TRIANGLE_STRIP
for (int j = 2; j < ic; j++) {
facesw[widx++] = vr[ir[j - 2]];
facesw[widx++] = vr[ir[j - 1]];
facesw[widx++] = vr[ir[j]];
}
}
} else {
for (int j = 0; j < vc; j++) {
facesw[widx++] = vr[j];
if (primitive == PRIMITIVE_TRIANGLES) {
for (int j = 0; j < vc; j++) {
facesw[widx++] = vr[j];
}
} else { // PRIMITIVE_TRIANGLE_STRIP
for (int j = 2; j < vc; j++) {
facesw[widx++] = vr[j - 2];
facesw[widx++] = vr[j - 1];
facesw[widx++] = vr[j];
}
}
}
}