Files @ r24874:b9bdc5d49a71
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Location: cpp/openttd-patchpack/source/src/viewport_func.h

Patric Stout
Fix #6319: [Win32] don't use clipping; draw whole screen every frame (#8726)

When we clip the region that is only been redrawn, something
weird happens on Windows. When pushing 60 frames per second on a
60Hz monitor, it appears that the clipped region is often shown
of another frame, instead of the current.

Examples of this are:
- pause the game, move your mouse to the left, and at the right
speed it totally disappears.
- fast aircrafts seem to be in several places at once, weirdly
lagging behind.
- in title screen, moving your mouse gives you the idea it is
jumping places, instead of smooth movements.

In the end, if you do nothing, everything is correct, so it is
eventually consistent. Just when we are firing many BitBlt in
a clipped region, the in-between is not.

What goes wrong exactly, I honestly do not know. On every frame
that we push to the DC is a mouse painted, but visually it
sometimes appears like it is not. Recording with external software
shows it really is there.
It is also not our eyes playing tricks on us, as the first example
makes it really clear the mouse pointer really is not painted.

And to be clear, with the mouse this is easiest reproduceable,
as high-speed objects are influences by this most. But this happens
for all movement that redraws small regions.

Either way, not using clipped regions resolves the issue completely,
and there appears to be little to no penalty (I failed to measure
any impact of drawing the full screen). So better have a good game
than fast code, I guess?
/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file viewport_func.h Functions related to (drawing on) viewports. */

#ifndef VIEWPORT_FUNC_H
#define VIEWPORT_FUNC_H

#include "gfx_type.h"
#include "viewport_type.h"
#include "window_type.h"
#include "tile_map.h"
#include "station_type.h"

static const int TILE_HEIGHT_STEP = 50; ///< One Z unit tile height difference is displayed as 50m.

void SetSelectionRed(bool);

void DeleteWindowViewport(Window *w);
void InitializeWindowViewport(Window *w, int x, int y, int width, int height, uint32 follow_flags, ZoomLevel zoom);
Viewport *IsPtInWindowViewport(const Window *w, int x, int y);
Point TranslateXYToTileCoord(const Viewport *vp, int x, int y, bool clamp_to_map = true);
Point GetTileBelowCursor();
void UpdateViewportPosition(Window *w);

bool MarkAllViewportsDirty(int left, int top, int right, int bottom);

bool DoZoomInOutWindow(ZoomStateChange how, Window *w);
void ZoomInOrOutToCursorWindow(bool in, Window * w);
Point GetTileZoomCenterWindow(bool in, Window * w);
void FixTitleGameZoom();
void HandleZoomMessage(Window *w, const Viewport *vp, byte widget_zoom_in, byte widget_zoom_out);

/**
 * Zoom a viewport as far as possible in the given direction.
 * @param how Zooming direction.
 * @param w   Window owning the viewport.
 * @pre \a how should not be #ZOOM_NONE.
 */
static inline void MaxZoomInOut(ZoomStateChange how, Window *w)
{
	while (DoZoomInOutWindow(how, w)) {};
}

void OffsetGroundSprite(int x, int y);

void DrawGroundSprite(SpriteID image, PaletteID pal, const SubSprite *sub = nullptr, int extra_offs_x = 0, int extra_offs_y = 0);
void DrawGroundSpriteAt(SpriteID image, PaletteID pal, int32 x, int32 y, int z, const SubSprite *sub = nullptr, int extra_offs_x = 0, int extra_offs_y = 0);
void AddSortableSpriteToDraw(SpriteID image, PaletteID pal, int x, int y, int w, int h, int dz, int z, bool transparent = false, int bb_offset_x = 0, int bb_offset_y = 0, int bb_offset_z = 0, const SubSprite *sub = nullptr);
void AddChildSpriteScreen(SpriteID image, PaletteID pal, int x, int y, bool transparent = false, const SubSprite *sub = nullptr, bool scale = true);
void ViewportAddString(const DrawPixelInfo *dpi, ZoomLevel small_from, const ViewportSign *sign, StringID string_normal, StringID string_small, StringID string_small_shadow, uint64 params_1, uint64 params_2 = 0, Colours colour = INVALID_COLOUR);


void StartSpriteCombine();
void EndSpriteCombine();

bool HandleViewportClicked(const Viewport *vp, int x, int y);
void SetRedErrorSquare(TileIndex tile);
void SetTileSelectSize(int w, int h);
void SetTileSelectBigSize(int ox, int oy, int sx, int sy);

void ViewportDoDraw(const Viewport *vp, int left, int top, int right, int bottom);

bool ScrollWindowToTile(TileIndex tile, Window *w, bool instant = false);
bool ScrollWindowTo(int x, int y, int z, Window *w, bool instant = false);

void RebuildViewportOverlay(Window *w);

bool ScrollMainWindowToTile(TileIndex tile, bool instant = false);
bool ScrollMainWindowTo(int x, int y, int z = -1, bool instant = false);

void UpdateAllVirtCoords();
void ClearAllCachedNames();

extern Point _tile_fract_coords;

void MarkTileDirtyByTile(TileIndex tile, int bridge_level_offset, int tile_height_override);

/**
 * Mark a tile given by its index dirty for repaint.
 * @param tile The tile to mark dirty.
 * @param bridge_level_offset Height of bridge on tile to also mark dirty. (Height level relative to north corner.)
 * @ingroup dirty
 */
static inline void MarkTileDirtyByTile(TileIndex tile, int bridge_level_offset = 0)
{
	MarkTileDirtyByTile(tile, bridge_level_offset, TileHeight(tile));
}

Point GetViewportStationMiddle(const Viewport *vp, const Station *st);

struct Station;
struct Town;

void SetViewportCatchmentStation(const Station *st, bool sel);
void SetViewportCatchmentTown(const Town *t, bool sel);

#endif /* VIEWPORT_FUNC_H */