PLTT ("TTLP") - Palette
The palette section holds a table with all colors used in the sprite(s). The color information is squeezed into one WORD resulting in five bits per component (r, g, b) and one unused bit.
Table of Contents
Data Structure
Section Container
struct ContainerSectionPLTT
{
/* 0x0 */ struct NitroSectionHeader sectionHeader;
/* 0x8 */ struct ContainerPLTT sectionData;
}; // entry size = sectionHeader.lengthSection
| Field Name | Description | Data Type |
|---|---|---|
| sectionHeader | Header of this section. sectionHeader.signature = "TTLP". | NitroSectionHeader |
| sectionData | Content of this section. | ContainerPLTT |
PLTT Container
struct ContainerPLTT
{
// header
/* 0x0 */ uint64_t dimensions;
/* 0x8 */ uint32_t lengthDataColor;
/* 0xC */ uint32_t offsetDataColor;
// data
/* offsetDataColor */ struct Palette dataPalette[numberPalettes];
}; // entry size = lengthDataColor + offsetDataColor
| Field Name | Description | Data Type |
|---|---|---|
| dimensions | Palette configuration. Defines the max number of palettes and colors per palette. | uint64_t |
| lengthDataColor | Length of the color data section in bytes. | uint32_t |
| offsetDataColor | Offset to the color data section relative to ContainerPLTT. | uint32_t |
| dataPalette | Array of palettes holding the colors. numberPalettes can be everything from 1 to 16. | Palette[] |
Palette
struct Palette
{
/* 0x0 */ struct ColorRGB5 color[numberColors];
}; // entry size = numberColors * 2
| Field Name | Description | Data Type |
|---|---|---|
| color | Array of compressed RGB colors. numberColors is either 0x10 = 16, or 0x100 = 256. | ColorRGB5[] |
Color RGB5
struct ColorRGB5
{
/* 0x00 */ uint16_t red : 5; // 0b00000000'00011111
uint16_t green : 5; // 0b00000011'11100000
uint16_t blue : 5; // 0b01111100'00000000
}; // entry size = 0x2
| Field Name | Description | Data Type |
|---|---|---|
| red | Red color component, uint8_t displayRed = red << 3;. | uint16_t : 5 |
| green | Green color component, uint8_t displayGreen = green << 3;. | uint16_t : 5 |
| blue | Blue color component, uint8_t displayBlue = blue << 3;. | uint16_t : 5 |
Specification
Palette Dimension Configuration
The first eight bytes in ContainerPLTT are marked as dimensions. This is related to the number and size of the palettes within this PLTT section. Since the result of reading the raw value is not clear, an enumeration type has been defined:
enum DimensionPalette : uint64_t
{
PALETTE1_COLOR16 = 0x00000000'000A0004ULL, // 1 palette, 16 colors
PALETTE1_COLOR256 = 0x00000000'00000004ULL, // 1 palette, 256 colors
PALETTE16_COLOR16 = 0x00000000'00000003ULL, // max. 16 palettes, 16 colors
PALETTE16_COLOR256 = 0x00000001'00000004ULL // max. 16 palettes, 256 colors
};
This serves as a lookup table with four possible values. The number of colors per palette is set to either 16 or 256. The number of palettes can be limited to a lower value by the count map, if it is set to 16.