Game tiles rendering with too-wide or narrow pixels at 1x and 2x scale.

[clort81]

oBoE/sfml is rendering the tiles in the game-world screen at incorrect position.

This can be seen when screenshotting a 2x scaled game and scaling down the image 0.5x in GIMP etc.

[clort81]

Simply zooming-in on the game window rendered at 2.00 reveals the issue. I noticed this happening on rendered text as well!

[clort81]

Oh it also happens at 1x scale.

Please Notice: 1- it's not only happening at terrain tile boundaries, so the error is not placing tiles at wrong position - it's also widerning one column of the character sprite.

2- checking boe.graphics.cpp, i noticed mainPort.height was set to 1.97xxx while width was set to 2. Changing getMenubarHeight() in winutil.linux.cpp from return 1; to return 0; gave me an integer scale matching UIScale, but that didn't fix this problem.

3- Some text is also being drawn with 1-pixel offset. If I specify the same starting x in the rectangle boxes for the text dialogues, "Party status" and "Inventory" headers fail to line-up.

I think i will need to write simple test code to learn how SFML renders these things, and whether the problem is in BoE or SFML.

[retropipes]

Perhaps SFML and BoE aren't in agreement on the tile size, as BoE uses 28x36 tiles. Perhaps SFML just needs to be told that the tiles aren't square? This one's a mystery to me as well.

[clort81]

With 1x scaling, i'm getting a 'cross' of duplicate tiles in the center of the game world window, but no rendering errors outside of it. Notice the border pixmap (brown) also has duplicate rows/columns, not just terrain. But outside that rectangle, there aren't errors in this screenshot.

[retropipes]

This smells like an off-by-one error to me; maybe the map grid is one pixel wider than it should be, or the upper-left tiles are placed one pixel further left than intended, and SFML is compensating by scaling the center tiles slightly - if so, the cause is in BoE.

[clort81]

Thanks wldwzrd89 - but it's not just the map tiles. It's also the game world border, which is one contiguous .png file.

The borderfile is terscreen.png, which gets loaded to terrain_screen_gworld. The border rectangle is 278x350 pixels.

boe.graphics.cpp: clip_rect(terrain_screen_gworld, {13, 13, 337, 265}); sets a rectangle of 265x324 pixels. 324 is the height of the interior space drawn with tiles but afaict the width should be 252 pixels.

From a screenshot the border rectangle is rendered as 279x351 pixels at scale factor 1x.

-

[retropipes]

Huh. Maybe it's more complex than it appears. It's not impossible that a weird interaction of BoE image placement and SFML scaling is causing this, but teasing out the bad interactions is the tough part.

[CelticMinstrel]

The terrain (including the border) is first rendered to a render texture, then copied to the screen. It might be useful to dump the render texture and see if it already exhibits the duplicated pixels? I don't expect it will, but…