From a86eabc1f054cb52e0ee9bd499b45366af8ad6b5 Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Fri, 18 Apr 2025 18:48:28 +1000
Subject: [PATCH] Win32RawInputSource: Fix handling of absolute positioned
 devices

Maybe? Works in VMware now, I don't have any actual tablets.
---
 src/util/input_manager.cpp          |  4 +-
 src/util/input_manager.h            |  2 +-
 src/util/win32_raw_input_source.cpp | 67 +++++++++++++++++++++++------
 3 files changed, 56 insertions(+), 17 deletions(-)

diff --git a/src/util/input_manager.cpp b/src/util/input_manager.cpp
index 33c88adac..f6df56009 100644
--- a/src/util/input_manager.cpp
+++ b/src/util/input_manager.cpp
@@ -1283,9 +1283,9 @@ std::pair<float, float> InputManager::GetPointerAbsolutePosition(u32 index)
                         s_host_pointer_positions[index][static_cast<u8>(InputPointerAxis::Y)]);
 }
 
-void InputManager::UpdatePointerAbsolutePosition(u32 index, float x, float y)
+void InputManager::UpdatePointerAbsolutePosition(u32 index, float x, float y, bool raw_input)
 {
-  if (index >= MAX_POINTER_DEVICES || s_relative_mouse_mode_active) [[unlikely]]
+  if (index >= MAX_POINTER_DEVICES || (s_relative_mouse_mode_active && !raw_input)) [[unlikely]]
     return;
 
   const float dx = x - std::exchange(s_host_pointer_positions[index][static_cast<u8>(InputPointerAxis::X)], x);
diff --git a/src/util/input_manager.h b/src/util/input_manager.h
index 9cb1474f3..35a35aede 100644
--- a/src/util/input_manager.h
+++ b/src/util/input_manager.h
@@ -348,7 +348,7 @@ u32 GetPointerCount();
 std::pair<float, float> GetPointerAbsolutePosition(u32 index);
 
 /// Updates absolute pointer position. Can call from UI thread, use when the host only reports absolute coordinates.
-void UpdatePointerAbsolutePosition(u32 index, float x, float y);
+void UpdatePointerAbsolutePosition(u32 index, float x, float y, bool raw_input = false);
 
 /// Resets the accumulated pointer movement. Use when pointer tracking was interrupted.
 void ResetPointerRelativeDelta(u32 index);
diff --git a/src/util/win32_raw_input_source.cpp b/src/util/win32_raw_input_source.cpp
index a49bf0bbc..ca69d72ee 100644
--- a/src/util/win32_raw_input_source.cpp
+++ b/src/util/win32_raw_input_source.cpp
@@ -3,6 +3,9 @@
 
 #include "win32_raw_input_source.h"
 #include "input_manager.h"
+#include "platform_misc.h"
+
+#include "core/gpu_thread.h"
 
 #include "common/assert.h"
 #include "common/error.h"
@@ -313,16 +316,6 @@ bool Win32RawInputSource::ProcessRawInputEvent(const RAWINPUT* event)
 
       const RAWMOUSE& rm = event->data.mouse;
 
-      s32 dx = rm.lLastX;
-      s32 dy = rm.lLastY;
-
-      // handle absolute positioned devices
-      if ((rm.usFlags & MOUSE_MOVE_ABSOLUTE) == MOUSE_MOVE_ABSOLUTE)
-      {
-        dx -= std::exchange(dx, state.last_x);
-        dy -= std::exchange(dy, state.last_y);
-      }
-
       unsigned long button_mask =
         (rm.usButtonFlags & (rm.usButtonFlags ^ std::exchange(state.button_state, rm.usButtonFlags))) &
         ALL_BUTTON_MASKS;
@@ -341,10 +334,56 @@ bool Win32RawInputSource::ProcessRawInputEvent(const RAWINPUT* event)
         button_mask &= ~(1u << bit_index);
       }
 
-      if (dx != 0)
-        InputManager::UpdatePointerRelativeDelta(pointer_index, InputPointerAxis::X, static_cast<float>(dx), true);
-      if (dy != 0)
-        InputManager::UpdatePointerRelativeDelta(pointer_index, InputPointerAxis::Y, static_cast<float>(dy), true);
+      // handle absolute positioned devices
+      if ((rm.usFlags & MOUSE_MOVE_ABSOLUTE) == MOUSE_MOVE_ABSOLUTE)
+      {
+        // https://learn.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-rawmouse#remarks
+        RECT rect;
+        if (rm.usFlags & MOUSE_VIRTUAL_DESKTOP)
+        {
+          rect.left = GetSystemMetrics(SM_XVIRTUALSCREEN);
+          rect.top = GetSystemMetrics(SM_YVIRTUALSCREEN);
+          rect.right = GetSystemMetrics(SM_CXVIRTUALSCREEN);
+          rect.bottom = GetSystemMetrics(SM_CYVIRTUALSCREEN);
+        }
+        else
+        {
+          rect.left = 0;
+          rect.top = 0;
+          rect.right = GetSystemMetrics(SM_CXSCREEN);
+          rect.bottom = GetSystemMetrics(SM_CYSCREEN);
+        }
+
+        int absolute_x = MulDiv(rm.lLastX, rect.right, USHRT_MAX) + rect.left;
+        int absolute_y = MulDiv(rm.lLastY, rect.bottom, USHRT_MAX) + rect.top;
+
+        // This is truely awful. But for something that isn't used much, it's the easiest way to get the render rect...
+        const WindowInfo& render_wi = GPUThread::GetRenderWindowInfo();
+        if (render_wi.type == WindowInfo::Type::Win32 &&
+            GetWindowRect(static_cast<HWND>(render_wi.window_handle), &rect))
+        {
+          absolute_x -= rect.left;
+          absolute_y -= rect.top;
+        }
+
+        InputManager::UpdatePointerAbsolutePosition(pointer_index, static_cast<float>(absolute_x),
+                                                    static_cast<float>(absolute_y), true);
+      }
+      else
+      {
+        // relative is easy
+        if (rm.lLastX != 0)
+        {
+          InputManager::UpdatePointerRelativeDelta(pointer_index, InputPointerAxis::X, static_cast<float>(rm.lLastX),
+                                                   true);
+        }
+
+        if (rm.lLastY != 0)
+        {
+          InputManager::UpdatePointerRelativeDelta(pointer_index, InputPointerAxis::Y, static_cast<float>(rm.lLastY),
+                                                   true);
+        }
+      }
 
       return true;
     }