The PaletteOffset() API allows you to easily calculate the color ID index when using palette mode in the Pixel Vision OS Color Tool. When switching to palette mode, the ColorChip’s memory is split into 128 system colors and 128 palette colors. Palettes start as ID 127. Each palette can contain a maximum of 16 colors which ends up giving you 8 palettes to work with.
By calling the PaletteOffset() API, it will convert a palette ID into the correct color ID for you. When used in the place of any of the drawing API’s colorOffset arguments, you can easily shift between any of the 8 palettes during run-time. There is an optional argument to supply a paletteColorID which gives you the color ID for a specific position inside of the palette.
PaletteOffset ( paletteID, paletteColorID)| Name | Value | Description |
|---|---|---|
| paletteID | int | A palette number between 0 and 7. |
| paletteColorID | int | An optional color ID inside of a palette between 0 and 15. This is set to 0 by default. |
| Value | Description |
|---|---|
| int | Returns a color ID based on the palette and palette color value. |
In this example, we are going to increase and decrease the palette ID value to give the effect that the sprites are fading into the background. To do this, we need to set up several palettes in the Color Tool to create the effect:
With the palettes created, we can shift between them by calling PaletteOffset() to calculate the correct color ID to use for the color offset. Running this code will output the following:
-- Set up a time and delay
local time = 0
local delay = 800
-- This will be the direction value for the transition
local dir = 1
-- Total number of palettes for transition
local max = 4
-- Current palette ID
local paletteID = 0
function Init()
-- Example Title
DrawText("PaletteOffset()", 8, 8, DrawMode.TilemapCache, "large", 15)
DrawText("Lua Example", 8, 16, DrawMode.TilemapCache, "medium", 15, -4)
-- Draw the text for the palette and color ID
DrawText("Palette (Color ID )", 1, 4, DrawMode.Tile, "large", 15)
end
function Update(timeDelta)
-- Increase the time on each frame and test if it is greater than the delay
time = time + timeDelta
if(time > delay) then
-- Update the palette ID based on the direction
paletteID = paletteID + dir
-- Test if the palette ID is too small or too large and reverse the direction
if(paletteID >= max) then
dir = -1
elseif(paletteID <= 0) then
dir = 1
end
-- Reset the time value
time = 0
end
end
function Draw()
-- Redraw the display
RedrawDisplay()
-- Draw the sprite block using the current palette offset value
DrawMetaSprite("lock", 8, 48, false, false, DrawMode.Sprite, PaletteOffset(paletteID))
-- Draw the current palette number and color offset value
DrawText(paletteID, 72, 32, DrawMode.Sprite, "large", 14)
DrawText(PaletteOffset(paletteID), 168, 32, DrawMode.Sprite, "large", 14)
end
namespace PixelVision8.Player
{
class PaletteOffsetExample : GameChip
{
// Set up a time and delay
private int time = 0;
private int delay = 800;
// This will be the direction value for the transition
private int dir = 1;
// Total number of palettes for transition
private int max = 4;
// Current palette ID
private int paletteID = 0;
public override void Init()
{
// Example Title
DrawText("PaletteOffset()", 8, 8, DrawMode.TilemapCache, "large", 15);
DrawText("C Sharp Example", 8, 16, DrawMode.TilemapCache, "medium", 15, -4);
// Draw the text for the palette and color ID
DrawText("Palette (Color ID )", 1, 4, DrawMode.Tile, "large", 15);
}
public override void Update(int timeDelta)
{
// Increase the time on each frame and test if it is greater than the delay
time = time + timeDelta;
if (time > delay)
{
// Update the palette ID based on the direction
paletteID = paletteID + dir;
// Test if the palette ID is too small or too large and reverse the direction
if (paletteID >= max)
{
dir = -1;
}
else if (paletteID <= 0)
{
dir = 1;
}
// Reset the time value
time = 0;
}
}
public override void Draw()
{
// Redraw the display
RedrawDisplay();
// Draw the sprite block using the current palette offset value
DrawMetaSprite("lock", 8, 48, false, false, DrawMode.Sprite, PaletteOffset(paletteID));
// Draw the current palette number and color offset value
DrawText(paletteID.ToString(), 72, 32, DrawMode.Sprite, "large", 14);
DrawText(PaletteOffset(paletteID).ToString(), 168, 32, DrawMode.Sprite, "large", 14);
}
}
}