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#include "Primitives.hpp"
namespace MC::GFX::Util::Primitives {
PlanePrimitive plane(AABB aabb, FaceSet face) {
decltype(PlanePrimitive::positions) positions;
auto [min, max] = aabb;
switch (face) {
case FaceSet::Front:
positions = {{
{min.x(), min.y(), min.z()}, {min.x(), max.y(), min.z()},
{max.x(), max.y(), min.z()}, {max.x(), min.y(), min.z()}
}};
break;
case FaceSet::Back:
positions = {{
{min.x(), min.y(), max.z()}, {max.x(), min.y(), max.z()},
{max.x(), max.y(), max.z()}, {min.x(), max.y(), max.z()}
}};
break;
case FaceSet::Top:
positions = {{
{min.x(), max.y(), min.z()}, {min.x(), max.y(), max.z()},
{max.x(), max.y(), max.z()}, {max.x(), max.y(), min.z()}
}};
break;
case FaceSet::Bottom:
positions = {{
{min.x(), min.y(), min.z()}, {max.x(), min.y(), min.z()},
{max.x(), min.y(), max.z()}, {min.x(), min.y(), max.z()}
}};
break;
case FaceSet::Right:
positions = {{
{max.x(), min.y(), min.z()}, {max.x(), max.y(), min.z()},
{max.x(), max.y(), max.z()}, {max.x(), min.y(), max.z()}
}};
break;
case FaceSet::Left:
positions = {{
{min.x(), min.y(), min.z()}, {min.x(), min.y(), max.z()},
{min.x(), max.y(), max.z()}, {min.x(), max.y(), min.z()}
}};
break;
}
auto is_side = [=](FaceSet f) -> I8 { return f == face; };
Vector<3, F32> normal = {
is_side(FaceSet::Right) - is_side(FaceSet::Left),
is_side(FaceSet::Top) - is_side(FaceSet::Bottom),
is_side(FaceSet::Front) - is_side(FaceSet::Back),
};
return {positions, {normal, normal, normal, normal}, {0, 1, 2, 2, 3, 0}};
}
BoxPrimitive box(AABB aabb, FaceSet faces) {
BoxPrimitive box{};
auto [min, max] = aabb;
UInt set_faces = 0;
U8 face_value = 1;
for (UInt face_index = 0; face_index < FaceSet::Size; face_index++, face_value <<= 1) {
FaceSet face = (FaceSet::Value)face_value;
if ((faces & face) == 0) continue;
AABB face_aabb;
switch (face) {
case FaceSet::Front:
face_aabb = {min, {max.x(), max.y(), min.z()}};
break;
case FaceSet::Back:
face_aabb = {{min.x(), min.y(), max.z()}, max};
break;
case FaceSet::Top:
face_aabb = {{min.x(), max.y(), min.z()}, {max.x(), max.y(), max.z()}};
break;
case FaceSet::Bottom:
face_aabb = {min, {max.x(), min.y(), max.z()}};
break;
case FaceSet::Right:
face_aabb = {{max.x(), min.y(), min.z()}, max};
break;
case FaceSet::Left:
face_aabb = {min, {min.x(), max.y(), max.z()}};
break;
}
auto p = plane(face_aabb, face);
for (UInt i = 0; i < p.positions.size(); i++) {
box.positions[set_faces * 4 + i] = p.positions[i];
}
for (UInt i = 0; i < p.normals.size(); i++) {
box.normals[set_faces * 4 + i] = p.normals[i];
}
for (UInt i = 0; i < p.indices.size(); i++) {
box.indices[set_faces * 6 + i] = p.indices[i] + set_faces * 4;
}
set_faces++;
}
return box;
}
}
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