Age of Wonders: Shadow Magic - missing terrain

[WinterSnowfall]

Most likely another ProcessVertices limitation. The game seems to render just fine except for that.

[elishacloud]

I could be wrong here, but I don't think the issue is related to ProcessVertices. dxwrapper has support for ProcessVertices but still has an issue with black (or unrendered) backgrounds. If you figure out what is causing this issue please let me know. I haven't figured it out yet.

[WinterSnowfall]

Technically DXVK/D7VK also have support for ProcessVertices, however it's only partial, and missing terrain rendering is something I've noticed in few other games using ProcessVertices, like Praetorians. Apitrace support is slowly improving, so at some point this should become more debuggable. If I make any progress, I'll note it down here. These issues also serve as my "off-brain" memory most of the time 😉.

[WinterSnowfall]

If you figure out what is causing this issue please let me know. I haven't figured it out yet.

@elishacloud I think we've figured this one out. I'm paraphrasing @CkNoSFeRaTU here, since he looked at an actual trace, but the game does the following on startup or whenever the view changes:

• sets a plain off screen surface as the RT and draws the terrain to it, piece by piece
• when that is done it sets a new RT, the actual back buffer
• it copies the content from the plain off screen surface to the new RT

This all happens inside of the same scene (device Begin/EndScene() context). The problem we had in D7VK was that we didn't copy back the drawn image from d3d9 for that off screen surface, so the game was always blitting empty content on the RT instead of the terrain.

The (simple) fix was to fetch the d3d9 surface content back to DDraw images whenever the render target changes, assuming the surface had any content written to it in d3d9 (guess you could track based on draw calls here). I will push that in a bit, as it might be useful as reference, but I think adapting what I've described to your flows would fix the issue also.

[CkNoSFeRaTU]

I'll add that the game does this when entering in-game state or when you move the camera. Otherwise it copies that previously saved unlit background with resolution of visible viewport minus bottom panel without fog of war/units/structures to rt at the start of the frame and then re-renders everything on top of it. Also when populating that terrain background beforehand it creates a bunch of surfaces for tiles and then use these tiles as textures for draws to populate it periodically doing locks as well. And after switching rt and fastblt to new rt it releases this offscreen surface.

[WinterSnowfall]

Fixed in 0bf8064.

[elishacloud]

@WinterSnowfall, @CkNoSFeRaTU, thank you for the details here!