66 lines
1.9 KiB
C++
66 lines
1.9 KiB
C++
#include <iter.h>
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#include <iostream>
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struct Position {
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double x, y;
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};
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struct Velocity {
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double x, y;
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};
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struct Mass {
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double value;
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};
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int main(int, char *[]) {
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flecs::world ecs;
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// Create a query for Position, Velocity.
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flecs::query<Position, const Velocity> q =
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ecs.query<Position, const Velocity>();
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// Create a few test entities for a Position, Velocity query
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ecs.entity("e1")
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.set<Position>({10, 20})
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.set<Velocity>({1, 2});
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ecs.entity("e2")
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.set<Position>({10, 20})
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.set<Velocity>({3, 4});
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ecs.entity("e3")
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.set<Position>({10, 20})
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.set<Velocity>({4, 5})
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.set<Mass>({50});
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// The iter function provides a flecs::iter object which contains all sorts
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// of information on the entities currently being iterated.
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// The function passed to iter is by default called for each table the query
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// is matched with.
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q.iter([&](flecs::iter& it, Position *p, const Velocity *v) {
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// Print the table & number of entities matched in current callback
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std::cout << "Table [" << it.type().str() << "]" << std::endl;
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std::cout << " - number of entities: " << it.count() << std::endl;
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// Print information about the components being matched
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for (int i = 1; i <= it.field_count(); i ++) {
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std::cout << " - term " << i << ": " << std::endl;
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std::cout << " - component: " << it.id(i).str() << std::endl;
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std::cout << " - type size: " << it.size(i) << std::endl;
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}
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std::cout << std::endl;
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// Iterate entities
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for (auto i : it) {
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p[i].x += v[i].x;
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p[i].y += v[i].y;
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std::cout << " - " << it.entity(i).name() <<
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": {" << p[i].x << ", " << p[i].y << "}\n";
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}
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std::cout << std::endl;
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});
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}
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