From a81679191497b565238db29077ee7318be171f89 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Mon, 10 Jan 2022 12:20:52 -0700
Subject: [PATCH] Added setMouseScrollCallback

---
 lib/minifb/src/minifb.zig |  5 ++++
 src/main.zig              | 62 +++++++++++++++++++++++++++++++++++----
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/lib/minifb/src/minifb.zig b/lib/minifb/src/minifb.zig
index 744e422..7ad04b1 100644
--- a/lib/minifb/src/minifb.zig
+++ b/lib/minifb/src/minifb.zig
@@ -148,6 +148,11 @@ pub fn Window(comptime TUserData: type) type {
             c.mfb_set_mouse_move_callback(self.cwin, @ptrCast(c.mfb_mouse_move_func, callback));
         }
 
+        pub const MouseScrollFunc = fn (win: Window(TUserData), key_mod: KeyMod, delta_x: f32, delty_y: f32) callconv(.C) void;
+        pub fn setMouseScrollCallback(self: Window(TUserData), callback: MouseScrollFunc) void {
+            c.mfb_set_mouse_scroll_callback(self.cwin, @ptrCast(c.mfb_mouse_scroll_func, callback));
+        }
+
         pub fn setViewport(self: Window(TUserData), offset_x: u32, offset_y: u32, width: u32, height: u32) bool {
             return c.mfb_set_viewport(self.cwin, offset_x, offset_y, width, height);
         }
diff --git a/src/main.zig b/src/main.zig
index 6c9bfe6..75d8bf7 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -17,12 +17,30 @@ const Coords = struct {
     y: i32,
 };
 
+const FCoords = struct {
+    x: f32,
+    y: f32,
+
+    pub fn toCoords(self: FCoords) Coords {
+        return Coords{
+            .x = @floatToInt(i32, self.x),
+            .y = @floatToInt(i32, self.y),
+        };
+    }
+};
+
 const State = struct {
     period: f64,
     timer: *mfb.Timer,
     active: bool = true,
     alloc: std.mem.Allocator,
-    cursor: Coords = undefined,
+    cursor_pos: Coords = undefined,
+    rectangle_pos: FCoords = FCoords{
+        .x = @intToFloat(f32, Width) / 2.0,
+        .y = @intToFloat(f32, Height) / 2.0,
+    },
+    rectangle_width: f32 = @intToFloat(f32, Width) / 3.0,
+    rectangle_height: f32 = @intToFloat(f32, Height) / 3.0,
 
     pub fn init(alloc: std.mem.Allocator, period: f64) !State {
         var timer = try alloc.create(mfb.Timer);
@@ -48,13 +66,22 @@ const State = struct {
         const rectColor = if (self.active) mfb.Rgb{ .r = 0, .g = 255, .b = 0 } else mfb.Rgb{ .r = 255, .g = 0, .b = 0 };
 
         buf.drawRectangle(.{ .x = 0, .y = 0 }, .{ .x = Width, .y = Height }, grey(@floatToInt(u8, bgValue)));
-        buf.drawRectangle(.{ .x = Width / 3, .y = Height / 3 }, .{ .x = 2 * Width / 3, .y = 2 * Height / 3 }, rectColor);
-        buf.drawRectangle(.{ .x = 0, .y = 0 }, .{ .x = 10, .y = 10 }, mfb.Rgb{ .r = 0, .g = 0, .b = 255 });
+        buf.drawRectangle(
+            (FCoords{
+                .x = self.rectangle_pos.x - self.rectangle_width / 2,
+                .y = self.rectangle_pos.y - self.rectangle_height / 2,
+            }).toCoords(),
+            (FCoords{
+                .x = self.rectangle_pos.x + self.rectangle_width / 2,
+                .y = self.rectangle_pos.y + self.rectangle_height / 2,
+            }).toCoords(),
+            rectColor,
+        );
 
         // Draw cursor
         buf.drawRectangle(
-            .{ .x = self.cursor.x - CursorWidth / 2, .y = self.cursor.y - CursorWidth / 2 },
-            .{ .x = self.cursor.x + CursorWidth / 2, .y = self.cursor.y + CursorWidth / 2 },
+            .{ .x = self.cursor_pos.x - CursorWidth / 2, .y = self.cursor_pos.y - CursorWidth / 2 },
+            .{ .x = self.cursor_pos.x + CursorWidth / 2, .y = self.cursor_pos.y + CursorWidth / 2 },
             mfb.Rgb{ .r = 61, .g = 97, .b = 170 },
         );
     }
@@ -143,7 +170,29 @@ fn handleMouseButton(_: mfb.Window(State), mouse_button: mfb.MouseButton, key_mo
 }
 
 fn handleMouseMove(win: mfb.Window(State), x: i32, y: i32) callconv(.C) void {
-    win.getUserData().?.*.cursor = .{ .x = x, .y = y };
+    win.getUserData().?.*.cursor_pos = .{ .x = x, .y = y };
+}
+
+fn handleMouseScroll(win: mfb.Window(State), key_mod: mfb.KeyMod, delta_x: f32, delta_y: f32) callconv(.C) void {
+    _ = delta_x;
+
+    const scroll_speed = 3.5;
+
+    var state = win.getUserData().?;
+    std.log.info("scroll dx={d} dy={d}", .{ delta_x, delta_y });
+    if (key_mod.control) {
+        if (key_mod.shift) {
+            state.rectangle_width += delta_y * scroll_speed;
+        } else {
+            state.rectangle_height += delta_y * scroll_speed;
+        }
+    } else {
+        if (key_mod.shift) {
+            state.rectangle_pos.x += delta_y * scroll_speed;
+        } else {
+            state.rectangle_pos.y -= delta_y * scroll_speed;
+        }
+    }
 }
 
 pub fn main() !void {
@@ -163,6 +212,7 @@ pub fn main() !void {
     win.setResizeCallback(handleResize);
     win.setMouseButtonCallback(handleMouseButton);
     win.setMouseMoveCallback(handleMouseMove);
+    win.setMouseScrollCallback(handleMouseScroll);
 
     var buf = try Buffer.init(alloc, Width, Height);
     defer buf.deinit();