Port some OpenLoco helper functions (#13113)

* Port some OpenLoco helper functions

Added a few helper functions from OpenLoco to make viewport code a bit simpler

src/openrct2-ui/interface/ViewportInteraction.cpp

@@ -693,8 +693,7 @@ static Peep* viewport_interaction_get_closest_peep(ScreenCoordsXY screenCoords,
     if (viewport == nullptr || viewport->zoom >= 2)
         return nullptr;
 
-    screenCoords.x = ((screenCoords.x - viewport->pos.x) * viewport->zoom) + viewport->viewPos.x;
+    auto viewportCoords = viewport->ScreenToViewportCoord(screenCoords);
-    screenCoords.y = ((screenCoords.y - viewport->pos.y) * viewport->zoom) + viewport->viewPos.y;
 
     Peep* closestPeep = nullptr;
     auto closestDistance = std::numeric_limits<int32_t>::max();
@@ -703,8 +702,8 @@ static Peep* viewport_interaction_get_closest_peep(ScreenCoordsXY screenCoords,
         if (peep->sprite_left == LOCATION_NULL)
             continue;
 
-        auto distance = abs(((peep->sprite_left + peep->sprite_right) / 2) - screenCoords.x)
+        auto distance = abs(((peep->sprite_left + peep->sprite_right) / 2) - viewportCoords.x)
-            + abs(((peep->sprite_top + peep->sprite_bottom) / 2) - screenCoords.y);
+            + abs(((peep->sprite_top + peep->sprite_bottom) / 2) - viewportCoords.y);
         if (distance > maxDistance)
             continue;
 
@@ -748,7 +747,7 @@ CoordsXY sub_68A15E(const ScreenCoordsXY& screenCoords)
         waterHeight = info.Element->AsSurface()->GetWaterHeight();
     }
 
-    auto initialVPPos = screen_coord_to_viewport_coord(viewport, screenCoords);
+    auto initialVPPos = viewport->ScreenToViewportCoord(screenCoords);
     CoordsXY mapPos = initialPos + CoordsXY{ 16, 16 };
 
     for (int32_t i = 0; i < 5; i++)

src/openrct2/audio/Audio.cpp

@@ -223,12 +223,11 @@ namespace OpenRCT2::Audio
             if (viewport->flags & VIEWPORT_FLAG_SOUND_ON)
             {
                 int16_t vx = pos2.x - viewport->viewPos.x;
-                int16_t vy = pos2.y - viewport->viewPos.y;
                 params.pan = viewport->pos.x + (vx / viewport->zoom);
                 params.volume = SoundVolumeAdjust[static_cast<uint8_t>(soundId)]
                     + ((-1024 * viewport->zoom - 1) * (1 << volumeDown)) + 1;
 
-                if (vy < 0 || vy >= viewport->view_height || vx < 0 || vx >= viewport->view_width || params.volume < -10000)
+                if (!viewport->Contains(pos2) || params.volume < -10000)
                 {
                     params.in_range = false;
                     return params;

src/openrct2/interface/Viewport.cpp

@@ -1079,11 +1079,11 @@ std::optional<CoordsXY> screen_pos_to_map_pos(const ScreenCoordsXY& screenCoords
     return { mapCoords->ToTileStart() };
 }
 
-ScreenCoordsXY screen_coord_to_viewport_coord(rct_viewport* viewport, const ScreenCoordsXY& screenCoords)
+[[nodiscard]] ScreenCoordsXY rct_viewport::ScreenToViewportCoord(const ScreenCoordsXY& screenCoords) const
 {
     ScreenCoordsXY ret;
-    ret.x = ((screenCoords.x - viewport->pos.x) * viewport->zoom) + viewport->viewPos.x;
+    ret.x = ((screenCoords.x - pos.x) * zoom) + viewPos.x;
-    ret.y = ((screenCoords.y - viewport->pos.y) * viewport->zoom) + viewport->viewPos.y;
+    ret.y = ((screenCoords.y - pos.y) * zoom) + viewPos.y;
     return ret;
 }
 
@@ -1746,12 +1746,10 @@ static rct_viewport* viewport_find_from_point(const ScreenCoordsXY& screenCoords
     if (viewport == nullptr)
         return nullptr;
 
-    if (screenCoords.x < viewport->pos.x || screenCoords.y < viewport->pos.y)
+    if (viewport->ContainsScreen(screenCoords))
-        return nullptr;
+        return viewport;
-    if (screenCoords.x >= viewport->pos.x + viewport->width || screenCoords.y >= viewport->pos.y + viewport->height)
-        return nullptr;
 
-    return viewport;
+    return nullptr;
 }
 
 /**
@@ -1781,7 +1779,7 @@ std::optional<CoordsXY> screen_get_map_xy(const ScreenCoordsXY& screenCoords, rc
         return std::nullopt;
     }
 
-    auto start_vp_pos = screen_coord_to_viewport_coord(myViewport, screenCoords);
+    auto start_vp_pos = myViewport->ScreenToViewportCoord(screenCoords);
     CoordsXY cursorMapPos = info.Loc.ToTileCentre();
 
     // Iterates the cursor location to work out exactly where on the tile it is
@@ -1811,7 +1809,7 @@ std::optional<CoordsXY> screen_get_map_xy_with_z(const ScreenCoordsXY& screenCoo
         return std::nullopt;
     }
 
-    auto vpCoords = screen_coord_to_viewport_coord(viewport, screenCoords);
+    auto vpCoords = viewport->ScreenToViewportCoord(screenCoords);
     auto mapPosition = viewport_coord_to_map_coord(vpCoords, z);
     if (!map_is_location_valid(mapPosition))
     {

src/openrct2/interface/Viewport.h

@@ -136,7 +136,6 @@ void viewport_paint(
 
 CoordsXYZ viewport_adjust_for_map_height(const ScreenCoordsXY& startCoords);
 
-ScreenCoordsXY screen_coord_to_viewport_coord(rct_viewport* viewport, const ScreenCoordsXY& screenCoords);
 CoordsXY viewport_coord_to_map_coord(const ScreenCoordsXY& coords, int32_t z);
 std::optional<CoordsXY> screen_pos_to_map_pos(const ScreenCoordsXY& screenCoords, int32_t* direction);
 

src/openrct2/interface/Window.cpp

@@ -948,7 +948,7 @@ void window_viewport_get_map_coords_by_cursor(
     auto mouseCoords = context_get_cursor_position_scaled();
 
     // Compute map coordinate by mouse position.
-    auto viewportPos = screen_coord_to_viewport_coord(w->viewport, mouseCoords);
+    auto viewportPos = w->viewport->ScreenToViewportCoord(mouseCoords);
     auto coordsXYZ = viewport_adjust_for_map_height(viewportPos);
     auto mapCoords = viewport_coord_to_map_coord(viewportPos, coordsXYZ.z);
     *map_x = mapCoords.x;

src/openrct2/interface/Window.h

@@ -147,6 +147,22 @@ struct rct_viewport
     ZoomLevel zoom;
     uint8_t var_11;
     VisibilityCache visibility;
+
+    // Use this function on coordinates that are relative to the viewport zoom i.e. a peeps x, y position after transforming
+    // from its x, y, z
+    [[nodiscard]] constexpr bool Contains(const ScreenCoordsXY& vpos) const
+    {
+        return (
+            vpos.y >= viewPos.y && vpos.y < viewPos.y + view_height && vpos.x >= viewPos.x && vpos.x < viewPos.x + view_width);
+    }
+
+    // Use this function on coordinates that are relative to the screen that is been drawn i.e. the cursor position
+    [[nodiscard]] constexpr bool ContainsScreen(const ScreenCoordsXY& sPos) const
+    {
+        return (sPos.x >= pos.x && sPos.x < pos.x + width && sPos.y >= pos.y && sPos.y < pos.y + height);
+    }
+
+    [[nodiscard]] ScreenCoordsXY ScreenToViewportCoord(const ScreenCoordsXY& screenCoord) const;
 };
 
 /**

src/openrct2/world/Footpath.cpp

@@ -283,7 +283,7 @@ CoordsXY footpath_get_coordinates_from_pos(const ScreenCoordsXY& screenCoords, i
         }
     }
 
-    auto start_vp_pos = screen_coord_to_viewport_coord(viewport, screenCoords);
+    auto start_vp_pos = viewport->ScreenToViewportCoord(screenCoords);
 
     for (int32_t i = 0; i < 5; i++)
     {