First seen on Pocket OS v1.1 beta 7 and still remains as of v1.1, v1.2, v2.0, and v2.1. Untested on versions prior to v1.1 beta 7.
This issue is also present in spiritualized1997's openFPGA GBC core, but not in budude's core.
Description
In various games for Game Boy and Game Boy Color, whenever a sprite is close to the edge of the screen, the rightmost column of pixels is not visible on the screen. This appears to happen when the sprite's X-position (e.g. OAM addresses 0xFE01, 0xFE05, 0xFE09, etc.) is 0xA7. This is easier to spot in some situations than others, and is easiest to see if the sprite doesn't move horizontally or moves at a consistent pace, and if there are multiple sprites adjacent to one another vertically.
Below are some examples of comparison screenshots: The left is a screenshot from the Pocket, and the right is a screenshot from the BGB emulator. BGB is consistent with real hardware in this situation.
Keitai Denjuu Telefang
Pocket
bgb
This example is particularly easy to spot, and can be seen a cutscene that appears if the user doesn't press anything on the title screen. The Shigeki metasprite is made up of several smaller 8x8 sprites and these move left at a consistent pace, making this issue easily visible several times in the cutscene.
Super Mario Bros. Deluxe
Pocket
bgb
Notice that on the Pocket, the white pixels on the Paratroopa are missing since these pixels are on the rightmost column.
Wario Land: Super Mario Land 3
Pocket
bgb
Pixels on the right of the door to the treasure room are missing (see to the right of the eyes of the unlocked door).
Firmware versions
First seen on Pocket OS v1.1 beta 7 and still remains as of v1.1, v1.2, v2.0, and v2.1. Untested on versions prior to v1.1 beta 7.
This issue is also present in spiritualized1997's openFPGA GBC core, but not in budude's core.
Description
In various games for Game Boy and Game Boy Color, whenever a sprite is close to the edge of the screen, the rightmost column of pixels is not visible on the screen. This appears to happen when the sprite's X-position (e.g. OAM addresses 0xFE01, 0xFE05, 0xFE09, etc.) is 0xA7. This is easier to spot in some situations than others, and is easiest to see if the sprite doesn't move horizontally or moves at a consistent pace, and if there are multiple sprites adjacent to one another vertically.
Below are some examples of comparison screenshots: The left is a screenshot from the Pocket, and the right is a screenshot from the BGB emulator. BGB is consistent with real hardware in this situation.
Keitai Denjuu Telefang
This example is particularly easy to spot, and can be seen a cutscene that appears if the user doesn't press anything on the title screen. The Shigeki metasprite is made up of several smaller 8x8 sprites and these move left at a consistent pace, making this issue easily visible several times in the cutscene.
Super Mario Bros. Deluxe
Notice that on the Pocket, the white pixels on the Paratroopa are missing since these pixels are on the rightmost column.
Wario Land: Super Mario Land 3
Pixels on the right of the door to the treasure room are missing (see to the right of the eyes of the unlocked door).