ebiten: add DrawImageOptions.DisableMipmaps and DrawTrianglesOptions.DisableMipmaps

[hajimehoshi]

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• OpenBSD
• Android
• iOS
• Nintendo Switch
• PlayStation 5
• Xbox
• Web Browsers

What feature would you like to be added?

We found some cases that mipmap increased draw calls unexpectedly. For example, when we created a shadow for a text, we created an offscreen with a shrunk text by x1/12 = 8.3% with the linear filter, and enlarged it by x12 with the linear filter.

The problem is, mipmap images were unexpectedly created. To make matters worse, pixels were unexpectedly from GPU in the restoration logic for Android.

In this shadow case, we don't need mipmaps. Even without mipmaps, the rendering result didn't look changed. Let's add an option to disable mipmap.

/CC @wasedaigo

Why is this needed?

In order to improve performance, especially for Android.

[hajimehoshi]