From dbe5a92b540a38fa9118e8abbcf5e93ceed7d080 Mon Sep 17 00:00:00 2001
From: geemili <opensource@geemili.xyz>
Date: Thu, 29 Feb 2024 13:13:09 -0700
Subject: [PATCH] fix: don't crash if joystick doesn't have expected inputs

My laptop and desktop both have devices that appear as joysticks, but are
very clearly not. Before this change this meant that I couldn't test the
game on desktop after adding joystick support.
---
 src/main.zig | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index 43f3d88..d34b0e1 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -249,7 +249,7 @@ pub fn main() !void {
                 input_state.up = input_state.up or gamepad_state.buttons[seizer.backend.glfw.c.GLFW_GAMEPAD_BUTTON_DPAD_UP] != 0;
                 input_state.down = input_state.down or gamepad_state.buttons[seizer.backend.glfw.c.GLFW_GAMEPAD_BUTTON_DPAD_DOWN] != 0;
             }
-        } else if (seizer.backend.glfw.c.glfwJoystickPresent(seizer.backend.glfw.c.GLFW_JOYSTICK_1) != 0) {
+        } else if (seizer.backend.glfw.c.glfwJoystickPresent(seizer.backend.glfw.c.GLFW_JOYSTICK_1) != 0) handle_joystick: {
             var controller_input_state = InputState{
                 .left = false,
                 .right = false,
@@ -259,10 +259,20 @@ pub fn main() !void {
                 .undo = false,
             };
 
+            // get hats and buttons
             var hats_count: c_int = undefined;
-            const hats_ptr = seizer.backend.glfw.c.glfwGetJoystickHats(seizer.backend.glfw.c.GLFW_JOYSTICK_1, &hats_count);
+            const hats_ptr = seizer.backend.glfw.c.glfwGetJoystickHats(seizer.backend.glfw.c.GLFW_JOYSTICK_1, &hats_count) orelse break :handle_joystick;
             const hats = hats_ptr[0..@intCast(hats_count)];
 
+            var buttons_count: c_int = undefined;
+            const buttons_ptr = seizer.backend.glfw.c.glfwGetJoystickButtons(seizer.backend.glfw.c.GLFW_JOYSTICK_1, &buttons_count) orelse break :handle_joystick;
+            const buttons = buttons_ptr[0..@intCast(buttons_count)];
+
+            // check that the joystick has enough inputs
+            if (hats.len < 1) break :handle_joystick;
+            if (buttons.len < 2) break :handle_joystick;
+
+            // handle hat inputs
             const HAT_UP = seizer.backend.glfw.c.GLFW_HAT_UP;
             const HAT_RIGHT = seizer.backend.glfw.c.GLFW_HAT_RIGHT;
             const HAT_DOWN = seizer.backend.glfw.c.GLFW_HAT_DOWN;
@@ -273,9 +283,7 @@ pub fn main() !void {
             controller_input_state.up = hats[0] & HAT_UP != 0;
             controller_input_state.down = hats[0] & HAT_DOWN != 0;
 
-            var buttons_count: c_int = undefined;
-            const buttons_ptr = seizer.backend.glfw.c.glfwGetJoystickButtons(seizer.backend.glfw.c.GLFW_JOYSTICK_1, &buttons_count);
-            const buttons = buttons_ptr[0..@intCast(buttons_count)];
+            // handle button inputs
             controller_input_state.action = buttons[0] != 0;
             controller_input_state.undo = buttons[1] != 0;