Custom OSGL Image Format

info

This format is used internally by OSGL and is not related to rendering images on the screen. If you're interested in the file structure, please continue reading.

An OSGL texture is generated by image-converter. The texture, represented as a dictionary, contains three keys:

• width: The width of the texture as a number.
• height: The height of the texture as a number.
• pixels: The raw pixel data of the texture as a buffer.

Colors

Colors are stored as 32-bit unsigned integers (u32). This allows for compact representation and fast manipulation of colors as single numbers.

Each 32-bit color value consists of four 8-bit components: Red, Green, Blue, and Alpha (opacity). These components are packed into the 32-bit integer, with each component occupying one byte (8 bits).

Byte Layout of the Color

The four components are stored in the following order, from the most significant byte to the least significant byte:

• First byte (bits 1-8): Red (R)
• Second byte (bits 9-16): Green (G)
• Third byte (bits 17-24): Blue (B)
• Fourth byte (bits 25-32): Alpha (A)

This can be visualized as:

R	G	B	A
8 bits	8 bits	8 bits	8 bits
1-8	9-16	17-24	25-32

For example, consider a color with the following components:

• Red (R): 255 (0xFF)
• Green (G): 128 (0x80)
• Blue (B): 64 (0x40)
• Alpha (A): 255 (0xFF)

These components would be packed into a 32-bit integer as follows:

• Red (R): 255 (0xFF) -> Occupies bits 24-31
• Green (G): 128 (0x80) -> Occupies bits 16-23
• Blue (B): 64 (0x40) -> Occupies bits 8-15
• Alpha (A): 255 (0xFF) -> Occupies bits 0-7

The resulting 32-bit integer representation would be: 0xFF8040FF (4286595327).