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Cleanup: use openvdb matrices properly 

Before I was double confused about how openvdb stores its
transformation matrices. Now, I know they have the same layout
physically in memory, but are logically transposed (i.e. the translation
is in the last row instead of in the last column).
This commit is contained in:
Jacques Lucke 2020-10-12 14:24:25 +02:00
parent e3ad392b98
commit 60ba69ffb5
1 changed files with 14 additions and 13 deletions
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27
source/blender/modifiers/intern/MOD_volume_displace.cc
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@ -136,18 +136,17 @@ static void panelRegister(ARegionType *region_type)
static openvdb::Mat4s matrix_to_openvdb(const float m[4][4])
{
/* This constructor expects floats in row-major form. Therefore the matrix is transposed
* afterwards. */
/* Openvdb matrices are transposed Blender matrices, i.e. the translation is in the last row
* instead of in the last column. However, the layout in memory is the same, because openvdb
* matrices are row major (compared to Blender's column major matrices). */
openvdb::Mat4s new_matrix{reinterpret_cast<const float *>(m)};
new_matrix = new_matrix.transpose();
return new_matrix;
}
template<typename GridType> struct DisplaceOp {
/* Has to be copied for each thread. */
typename GridType::ConstAccessor accessor;
/* This is the transform of the grid that is being displaced. */
openvdb::Mat4s index_to_texture;
const openvdb::Mat4s index_to_texture;
Tex *texture;
const double strength;
@ -167,9 +166,11 @@ template<typename GridType> struct DisplaceOp {
openvdb::Vec3d compute_displace_vector(const openvdb::Coord &coord) const
{
if (this->texture != NULL) {
const openvdb::Vec3f texture_pos = this->index_to_texture * coord.asVec3s();
openvdb::Vec3d displace_vector = this->evaluate_texture(texture_pos);
return (displace_vector - this->texture_mid_level) * this->strength;
const openvdb::Vec3f texture_pos = coord.asVec3s() * this->index_to_texture;
const openvdb::Vec3d texture_value = this->evaluate_texture(texture_pos);
const openvdb::Vec3d displacement = (texture_value - this->texture_mid_level) *
this->strength;
return displacement;
}
return openvdb::Vec3d{0, 0, 0};
}
@ -185,9 +186,8 @@ template<typename GridType> struct DisplaceOp {
static float get_max_voxel_side_length(const openvdb::GridBase &grid)
{
const openvdb::Mat3d matrix = grid.transform().baseMap()->getAffineMap()->getMat4().getMat3();
const float max_voxel_side_length = std::max(
{matrix.col(0).length(), matrix.col(1).length(), matrix.col(2).length()});
const openvdb::Vec3d voxel_size = grid.voxelSize();
const float max_voxel_side_length = std::max({voxel_size[0], voxel_size[1], voxel_size[2]});
return max_voxel_side_length;
}
@ -266,7 +266,7 @@ struct DisplaceGridOp {
}
case MOD_VOLUME_DISPLACE_MAP_GLOBAL: {
const openvdb::Mat4s object_to_world = matrix_to_openvdb(ctx.object->obmat);
return object_to_world * index_to_object;
return index_to_object * object_to_world;
}
case MOD_VOLUME_DISPLACE_MAP_OBJECT: {
if (vdmd.texture_map_object == NULL) {
@ -274,9 +274,10 @@ struct DisplaceGridOp {
}
const openvdb::Mat4s object_to_world = matrix_to_openvdb(ctx.object->obmat);
const openvdb::Mat4s world_to_texture = matrix_to_openvdb(vdmd.texture_map_object->imat);
return world_to_texture * object_to_world * index_to_object;
return index_to_object * object_to_world * world_to_texture;
}
}
BLI_assert(false);
return {};
}
};