feat: highlight selected card, change highlight card

src/main.zig

@@ -226,6 +226,10 @@ pub fn main() !void {
     gl.makeBindingCurrent(&gl_binding);
 
     // Set up input callbacks
+    var input_state: InputState = undefined;
+    _ = seizer.backend.glfw.c.glfwSetWindowUserPointer(window, &input_state);
+
+    _ = seizer.backend.glfw.c.glfwSetKeyCallback(window, &glfw_key_callback);
     _ = seizer.backend.glfw.c.glfwSetFramebufferSizeCallback(window, &glfw_framebuffer_size_callback);
 
     var card_tilemap_small: ?DeckSprites = null;
@@ -244,9 +248,21 @@ pub fn main() !void {
     var game_state = try GameState.init(gpa.allocator(), std.crypto.random.int(u64), 1);
     defer game_state.deinit();
 
+    var selection: usize = 0;
+
     while (seizer.backend.glfw.c.glfwWindowShouldClose(window) != seizer.backend.glfw.c.GLFW_TRUE) {
+        input_state = .{
+            .left = false,
+            .right = false,
+            .up = false,
+            .down = false,
+        };
         seizer.backend.glfw.c.glfwPollEvents();
 
+        if (input_state.right) {
+            selection = (selection + 1) % game_state.hands[0].items.len;
+        }
+
         gl.clearColor(0.7, 0.5, 0.5, 1.0);
         gl.clear(gl.COLOR_BUFFER_BIT);
 
@@ -317,10 +333,17 @@ pub fn main() !void {
         }
 
         for (game_state.hands[0].items, 0..) |card, i| {
-            deck_sprites.tilesheet.renderTile(&canvas, deck_sprites.getTileForCard(card), .{
+            const pos = [2]f32{
                 hand_pos[0] + @as(f32, @floatFromInt(i)) * @as(f32, @floatFromInt(deck_sprites.tilesheet.tile_size[0])),
                 hand_pos[1],
-            }, .{});
+            };
+            deck_sprites.tilesheet.renderTile(&canvas, deck_sprites.getTileForCard(card), pos, .{});
+            if (i == selection) {
+                canvas.rect(pos, [2]f32{
+                    @floatFromInt(deck_sprites.tilesheet.tile_size[0]),
+                    @floatFromInt(deck_sprites.tilesheet.tile_size[1]),
+                }, .{ .color = .{ 0xAA, 0xFF, 0xAA, 0x60 } });
+            }
         }
 
         canvas.end();
@@ -514,6 +537,29 @@ fn glfw_framebuffer_size_callback(window: ?*seizer.backend.glfw.c.GLFWwindow, wi
     );
 }
 
+const InputState = struct {
+    left: bool,
+    right: bool,
+    up: bool,
+    down: bool,
+};
+
+fn glfw_key_callback(window: ?*seizer.backend.glfw.c.GLFWwindow, key: c_int, scancode: c_int, action: c_int, mods: c_int) callconv(.C) void {
+    const input_state = @as(*InputState, @alignCast(@ptrCast(seizer.backend.glfw.c.glfwGetWindowUserPointer(window))));
+
+    _ = scancode;
+    _ = mods;
+    if (action == seizer.backend.glfw.c.GLFW_PRESS) {
+        switch (key) {
+            seizer.backend.glfw.c.GLFW_KEY_LEFT => input_state.left = true,
+            seizer.backend.glfw.c.GLFW_KEY_RIGHT => input_state.right = true,
+            seizer.backend.glfw.c.GLFW_KEY_UP => input_state.up = true,
+            seizer.backend.glfw.c.GLFW_KEY_DOWN => input_state.down = true,
+            else => {},
+        }
+    }
+}
+
 const seizer = @import("seizer");
 const gl = seizer.gl;
 const std = @import("std");