test: add tests for minecart movement along rail networks

tests/testMinecart.cpp

@@ -0,0 +1,209 @@
+#include "testHarness.h"
+#include "vf/Minecart.h"
+
+using namespace vf;
+
+namespace {
+
+auto neverPowered = [](const Vec3i&) { return false; };
+auto alwaysPowered = [](const Vec3i&) { return true; };
+
+void railLine(World& world, int x0, int x1, int y, int z, Block kind) {
+    for (int x = x0; x <= x1; ++x) world.setBlock(x, y, z, kind);
+}
+
+} // namespace
+
+VF_TEST(cartRollsAlongFlatTrackAndFrictionBringsItToRest) {
+    World world;
+    railLine(world, 0, 60, 0, 0, Block::Rail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.speed = 0.3f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(cart.speed < 0.3f);
+    CHECK(cart.offset > 0.0f);
+
+    for (int i = 0; i < 400; ++i) tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(!cart.derailed);
+    CHECK(cart.railPos.x > 5);
+    CHECK_NEAR(cart.speed, 0.0f, 1e-6f);
+}
+
+VF_TEST(poweredRailAcceleratesCartToMaxSpeed) {
+    World world;
+    railLine(world, 0, 300, 0, 0, Block::PoweredRail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.speed = 0.05f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, alwaysPowered, store);
+    CHECK(cart.speed > 0.05f);
+
+    for (int i = 0; i < 30; ++i) tickMinecart(world, cart, config, alwaysPowered, store);
+    CHECK_NEAR(cart.speed, config.maxSpeed, 1e-4f);
+    CHECK(!cart.derailed);
+}
+
+VF_TEST(inactivePoweredRailBrakesTheCart) {
+    World world;
+    railLine(world, 0, 60, 0, 0, Block::PoweredRail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.speed = 0.3f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(cart.speed < 0.2f);
+}
+
+VF_TEST(gravityAcceleratesCartDownASlope) {
+    World world;
+    world.setBlock(0, 0, 0, Block::Rail);
+    world.setBlock(-1, 0, 0, Block::Rail);
+    world.setBlock(1, 1, 0, Block::Rail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({0, 0, 0}, RailDir::West, CartKind::Empty);
+    cart.speed = 0.0f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(cart.speed > 0.04f);
+}
+
+VF_TEST(uphillDecelerationRollsTheCartBack) {
+    World world;
+    world.setBlock(0, 0, 0, Block::Rail);
+    world.setBlock(-1, 0, 0, Block::Rail);
+    world.setBlock(1, 1, 0, Block::Rail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({0, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.speed = 0.03f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(cart.moveDir == RailDir::West);
+    CHECK(cart.speed > 0.0f);
+}
+
+VF_TEST(cartDerailsWhenTrackEnds) {
+    World world;
+    world.setBlock(0, 0, 0, Block::Rail);
+    world.setBlock(1, 0, 0, Block::Rail);
+    ContainerStore store;
+
+    Minecart cart = makeMinecart({1, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.speed = 0.4f;
+    CartConfig config;
+
+    for (int i = 0; i < 12 && !cart.derailed; ++i)
+        tickMinecart(world, cart, config, neverPowered, store);
+    CHECK(cart.derailed);
+    CHECK_NEAR(cart.speed, 0.0f, 1e-6f);
+}
+
+VF_TEST(hopperCartPullsFromContainerAboveOnCooldown) {
+    World world;
+    world.setBlock(5, 0, 0, Block::Rail);
+    ContainerStore store;
+    store.ensure({5, 1, 0}, 5).insert(ItemId::Stone, 3);
+
+    Minecart cart = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Hopper);
+    cart.speed = 0.0f;
+    CartConfig config;
+
+    tickMinecart(world, cart, config, neverPowered, store);
+    CHECK_EQ(cart.inventory.totalItems(), 1);
+
+    for (int i = 0; i < 60; ++i) tickMinecart(world, cart, config, neverPowered, store);
+    CHECK_EQ(cart.inventory.totalItems(), 3);
+    CHECK_EQ(store.at({5, 1, 0})->totalItems(), 0);
+}
+
+VF_TEST(chestCartCarriesAnInventory) {
+    Minecart cart = makeMinecart({0, 0, 0}, RailDir::East, CartKind::Chest);
+    CHECK_EQ(cart.inventory.size(), chestCartSlots);
+    cart.inventory.insert(ItemId::DiamondGem, 12);
+    CHECK_EQ(cart.inventory.totalItems(), 12);
+}
+
+VF_TEST(cartWorldPositionTracksSubCellOffset) {
+    Minecart cart = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    cart.offset = 0.5f;
+    Vec3 pos = cartWorldPos(cart);
+    CHECK_NEAR(pos.x, 6.0f, 1e-5f);
+    CHECK_NEAR(pos.z, 0.5f, 1e-5f);
+}
+
+VF_TEST(headOnCartsBounceApart) {
+    World world;
+    railLine(world, -40, 40, 0, 0, Block::Rail);
+    ContainerStore store;
+    CartConfig config;
+
+    std::vector<Minecart> carts = {
+        makeMinecart({3, 0, 0}, RailDir::East, CartKind::Empty),
+        makeMinecart({7, 0, 0}, RailDir::West, CartKind::Empty),
+    };
+    carts[0].speed = 0.3f;
+    carts[1].speed = 0.3f;
+
+    for (int i = 0; i < 40; ++i)
+        stepMinecarts(world, carts, config, neverPowered, store);
+
+    CHECK(carts[0].moveDir == RailDir::West);
+    CHECK(carts[1].moveDir == RailDir::East);
+    CHECK(carts[0].railPos.x < carts[1].railPos.x);
+    CHECK(!carts[0].derailed);
+    CHECK(!carts[1].derailed);
+}
+
+VF_TEST(movingCartHandsMomentumToStationaryCart) {
+    World world;
+    railLine(world, -40, 40, 0, 0, Block::Rail);
+    ContainerStore store;
+    CartConfig config;
+
+    std::vector<Minecart> carts = {
+        makeMinecart({0, 0, 0}, RailDir::East, CartKind::Empty),
+        makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty),
+    };
+    carts[0].speed = 0.3f;
+    carts[1].speed = 0.0f;
+
+    for (int i = 0; i < 40; ++i)
+        stepMinecarts(world, carts, config, neverPowered, store);
+
+    CHECK(carts[1].speed > carts[0].speed);
+    CHECK(carts[1].railPos.x > carts[0].railPos.x);
+    CHECK(carts[0].speed < 0.05f);
+}
+
+VF_TEST(minecartSimulationIsDeterministic) {
+    World world;
+    railLine(world, 0, 300, 0, 0, Block::PoweredRail);
+    ContainerStore storeA, storeB;
+
+    Minecart a = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    Minecart b = makeMinecart({5, 0, 0}, RailDir::East, CartKind::Empty);
+    a.speed = 0.1f;
+    b.speed = 0.1f;
+    CartConfig config;
+
+    for (int i = 0; i < 50; ++i) {
+        tickMinecart(world, a, config, alwaysPowered, storeA);
+        tickMinecart(world, b, config, alwaysPowered, storeB);
+        CHECK(a.railPos == b.railPos);
+        CHECK(a.moveDir == b.moveDir);
+        CHECK_NEAR(a.speed, b.speed, 1e-6f);
+        CHECK_NEAR(a.offset, b.offset, 1e-6f);
+    }
+}