Color

Color is defined in the node table:

• Draw color is based on 8bit (0-255) RGBA: color_r, color_g, color_b and color_a.
• RGB values are updated when the user changes either: palette_id & color_id.
• RGBA values also effect Texture Maps.
• RGB color (auto) set using 'color_id' when color_r/g/b are all zero's.
• Black requires a valid ID pair, (ie: palette_id=0, color_id=19).

Users can set the color by palette index:

• Press '-' or '+' key to change color_id.
• Press ALT+'-' or ALT+'+' to change palette_id.
• Press '9' or '0' key to change (alpha) color_a.

Users can choose a custom RGBA color:

• Use the 'Color' tool to set a custom RGBA value using a (3D) mouse, ball, 6DoF stylus, etc.
• Custom colors are NOT based on palette ID's and will be lost if the user changes the color index.
• Note that the (color_a) alpha Transparency level is NOT effected when switching the color index.

3D models default to 100% white:

When the user changes the geometry to a custom 3D model, the RGB color is automatically set to full white (for texture mapping to appear in it's natural color). Also note that the color & palette ID's will be left unchanged. When switching the node back to the set of hard-coded (geo) primitives, the color will return to its original values.

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26 Hard-Coded Color Palettes

There are several hard-coded palettes:

• palette_id = 0 is a distinct set of 20 colors.
• palette_id = 1 is same as palette '0' but inverted.
• palette_id = 2 'Rainbow Heatmap' (a composite of gradients).
• palette_id = 3 'Rainbow Heatmap' inverted.
• palette_id's 4-25 are gradients with 256 color_id's each (0-255).
• Odd palette_id's are inverted colors (mirrors) of their Even numbered predecessor.
• Most palette's are linear gradients between two colors (ie: blue to green).

We plan to add more hard-coded and custom palettes in the future (ie: NWS heatmaps).

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Color Palette Code

Function npSetIndexColor() in 'npcolor.c' sets the RGBA color based on palette_id and color_id.

switch( paletteID )
{
	case 0 : // use indexed color array above
	case 1 : // odd cases are inverted after switch statement
		color->r = colorPalette[colorID][0];
		color->g = colorPalette[colorID][1];
		color->b = colorPalette[colorID][2];
		break;
	case 2 :		///< rainbow heatmap
	case 3 :		///< rainbow heatmap inverted
			if( colorID < 16 )			// light-pink to purple
			{
				color->r = 255 - colorID * 8;
				color->g = 127 - colorID * 8;
				color->b = 255 - colorID * 8;
			}
			else if( colorID < 32 )		// purple to blue-green
			{
				color->r = 255 - colorID * 8;
				color->g = (colorID - 16) * 8;
				color->b = (colorID - 16) * 8 + 127;
			}
			else if( colorID < 48 )		// blue-green to green
			{
				color->r = 0;
				color->g = 127 + (colorID - 32) * 8;
				color->b = 255 - (colorID - 32) * 16;
			}
			else if( colorID < 64 )		// green to yellow
			{
				color->r = (colorID - 48) * 16;
				color->g = 255;
				color->b = 0;
			}
			else if( colorID < 80 )		// yellow to orange
			{
				color->r = 255;
				color->g = 255 - (colorID - 64) * 8;
				color->b = 0;
			}
			else if( colorID < 96 )		// orange to red
			{
				color->r = 255;
				color->g = 127 - (colorID - 80) * 8;
				color->b = 0;
			}
			else if( colorID < 112 )	// red to dark-red
			{
				color->r = 255 - (colorID - 96) * 8;
				color->g = 0;
				color->b = 0;
			}
			else if( colorID < 128 )	// dark-red to light-pink
			{
				color->r = 127 + (colorID - 112) * 8;
				color->g = (colorID - 112) * 8;
				color->b = (colorID - 112) * 16;
			}
			break;
		case 4 :	// blue to green
		case 5 :	// inverted
			color->r = 0;
			color->g = colorID * 2;
			color->b = 255 - colorID * 2;
			break;
		case 6 :	// green to red
		case 7 :	// inverted
			color->r = colorID * 2;
			color->g = 255 - colorID * 2;
			color->b = 0;
			break;
		case 8 :	// blue to red
		case 9 :	// ...
			color->r = colorID * 2;
			color->g = 0;
			color->b = 255 - colorID * 2;
			break;
		case 10 :	// purple to yellow
		case 11 :
			color->r = 255;
			color->g = colorID * 2;
			color->b = 255 - colorID * 2;
			break;
		case 12 :	// black to red
		case 13 :
			color->r = colorID * 2;
			color->g = 0;
			color->b = 0;
			break;
		case 14 :	// black to green
		case 15 :
			color->r = 0;
			color->g = colorID * 2;
			color->b = 0;
			break;
		case 16 :	// black to blue
		case 17 :
			color->r = 0;
			color->g = 0;
			color->b = colorID * 2;
			break;
		case 18 :	// white to red
		case 19 :
			color->r = 255;
			color->g = 255 - colorID * 2;
			color->b = 255 - colorID * 2;
			break;
		case 20 :	// white to green
		case 21 :
			color->r = 255 - colorID * 2;
			color->g = 255;
			color->b = 255 - colorID * 2;
			break;
		case 22 :	// white to blue
		case 23 :
			color->r = 255 - colorID * 2;
			color->g = 255 - colorID * 2;
			color->b = 255;
			break;
		case 24 :	// black to white greyscale
		case 25 :
			color->r = colorID * 2;
			color->g = colorID * 2;
			color->b = colorID * 2;
			break;
	default :
			color->r = colorPalette[colorID][0];
			color->g = colorPalette[colorID][1];
			color->b = colorPalette[colorID][2];
		break;
}

/// if odd numbered paletteID then invert the color
if( paletteID & 1)
{ 
	color->r = 255 - color->r;
	color->g = 255 - color->g;
	color->b = 255 - color->b;
}