45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
#include <with.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 Npc { };
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int main(int, char *[]) {
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flecs::world ecs;
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// Create a query for Position, Npc. By adding the Npc component using the
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// "with" method, the component is not a part of the query type, and as a
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// result does not become part of the function signatures of each and iter.
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// This is useful for things like tags, which because they don't have a
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// value are less useful to pass to the each/iter functions as argument.
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flecs::query<Position> q = ecs.query_builder<Position>()
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.with<Npc>()
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.build();
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// Create a few test entities for the Position, Npc query
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ecs.entity("e1")
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.set<Position>({10, 20})
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.add<Npc>();
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ecs.entity("e2")
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.set<Position>({10, 20})
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.add<Npc>();
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// This entity will not match as it does not have Position, Npc
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ecs.entity("e3")
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.set<Position>({10, 20});
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// Note how the Npc tag is not part of the each signature
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q.each([](flecs::entity e, Position& p) {
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std::cout << e.name() << ": {" << p.x << ", " << p.y << "}\n";
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});
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// Output:
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// e1: {10, 20}
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// e2: {10, 20}
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}
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