Fix: Input processing on mobile devices with classic D-Pad control mode

core/src/main/java/org/geysermc/geyser/session/cache/InputCache.java

@@ -29,6 +29,7 @@ import lombok.Getter;
 import lombok.Setter;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.cloudburstmc.math.vector.Vector2f;
+import org.cloudburstmc.protocol.bedrock.data.InputInteractionModel;
 import org.cloudburstmc.protocol.bedrock.data.InputMode;
 import org.cloudburstmc.protocol.bedrock.data.PlayerAuthInputData;
 import org.cloudburstmc.protocol.bedrock.packet.PlayerAuthInputPacket;
@@ -61,14 +62,54 @@ public final class InputCache {
         var oldInputPacket = this.inputPacket;
         this.inputMode = packet.getInputMode();
 
+        /*
+        Brief introduction to how Bedrock sends movement inputs! It's mainly based on the following:
+        (as of 1.21.111)
+        1. inputmode:
+        - MOUSE: same as Java edition; will send up/down/left/right inputs via input flags
+        - GAMEPAD: indicates the use of a controller with joysticks, sends an "analogue movement vector" instead
+        - TOUCH: see interaction model!
+        - MOTION_CONTROLLER: what even is this
+
+        2. Interaction model (here, only really relevant for us when the inputmode is "touch"):
+        - CLASSIC: shows "wasd" keys on the client; like input-mode MOUSE would, additionally up_left / up_right / down_left / down_right
+        - CROSSHAIR / TOUCH: NO wasd, analogue movement vector instead
+
+        Hence, we'll also need to check for this fun edge-case!
+         */
+        boolean isMobileAndClassicMovement = inputMode == InputMode.TOUCH && packet.getInputInteractionModel() == InputInteractionModel.CLASSIC;
+
         boolean up, down, left, right;
-        if (this.inputMode == InputMode.MOUSE) {
+        if (this.inputMode == InputMode.MOUSE || isMobileAndClassicMovement) {
             up = bedrockInput.contains(PlayerAuthInputData.UP);
             down = bedrockInput.contains(PlayerAuthInputData.DOWN);
             left = bedrockInput.contains(PlayerAuthInputData.LEFT);
             right = bedrockInput.contains(PlayerAuthInputData.RIGHT);
+
+            if (isMobileAndClassicMovement) {
+                // These are the buttons in the corners of the touch area
+                if (bedrockInput.contains(PlayerAuthInputData.UP_LEFT)) {
+                    up = true;
+                    left = true;
+                }
+
+                if (bedrockInput.contains(PlayerAuthInputData.UP_RIGHT)) {
+                    up = true;
+                    right = true;
+                }
+
+                if (bedrockInput.contains(PlayerAuthInputData.DOWN_LEFT)) {
+                    down = true;
+                    left = true;
+                }
+
+                if (bedrockInput.contains(PlayerAuthInputData.DOWN_RIGHT)) {
+                    down = true;
+                    right = true;
+                }
+            }
         } else {
-            // The above flags don't fire TODO test console
+            // The above flags don't fire
             Vector2f analogMovement = packet.getAnalogMoveVector();
             up = analogMovement.getY() > 0;
             down = analogMovement.getY() < 0;
@@ -78,7 +119,6 @@ public final class InputCache {
 
         boolean sneaking = isSneaking(bedrockInput);
 
-        // TODO when is UP_LEFT, etc. used?
         this.inputPacket = this.inputPacket
             .withForward(up)
             .withBackward(down)
@@ -133,7 +173,7 @@ public final class InputCache {
     public boolean isSneaking(Set<PlayerAuthInputData> authInputData) {
         // Flying doesn't send start / stop fly cases; might as well return early
         if (session.isFlying()) {
-            // Of course e.g. mobile handles it differently with a descend case, while
+            // Of course e.g. mobile devices handle it differently with a descend case, while
             // e.g. Win10 sends SNEAK_DOWN. Why? We'll never know.
             return authInputData.contains(PlayerAuthInputData.DESCEND) || authInputData.contains(PlayerAuthInputData.SNEAK_DOWN);
         }