export default /* glsl */`
vec3 packNormalToRGB( const in vec3 normal ) {
return normalize( normal ) * 0.5 + 0.5;
}
vec3 unpackRGBToNormal( const in vec3 rgb ) {
return 2.0 * rgb.xyz - 1.0;
}
const float PackUpscale = 256. / 255.; // fraction -> 0..1 (including 1)
const float UnpackDownscale = 255. / 256.; // 0..1 -> fraction (excluding 1)
const float ShiftRight8 = 1. / 256.;
const float Inv255 = 1. / 255.;
const vec4 PackFactors = vec4( 1.0, 256.0, 256.0 * 256.0, 256.0 * 256.0 * 256.0 );
const vec2 UnpackFactors2 = vec2( UnpackDownscale, 1.0 / PackFactors.g );
const vec3 UnpackFactors3 = vec3( UnpackDownscale / PackFactors.rg, 1.0 / PackFactors.b );
const vec4 UnpackFactors4 = vec4( UnpackDownscale / PackFactors.rgb, 1.0 / PackFactors.a );
vec4 packDepthToRGBA( const in float v ) {
if( v <= 0.0 )
return vec4( 0., 0., 0., 0. );
if( v >= 1.0 )
return vec4( 1., 1., 1., 1. );
float vuf;
float af = modf( v * PackFactors.a, vuf );
float bf = modf( vuf * ShiftRight8, vuf );
float gf = modf( vuf * ShiftRight8, vuf );
return vec4( vuf * Inv255, gf * PackUpscale, bf * PackUpscale, af );
}
vec3 packDepthToRGB( const in float v ) {
if( v <= 0.0 )
return vec3( 0., 0., 0. );
if( v >= 1.0 )
return vec3( 1., 1., 1. );
float vuf;
float bf = modf( v * PackFactors.b, vuf );
float gf = modf( vuf * ShiftRight8, vuf );
// the 0.9999 tweak is unimportant, very tiny empirical improvement
// return vec3( vuf * Inv255, gf * PackUpscale, bf * 0.9999 );
return vec3( vuf * Inv255, gf * PackUpscale, bf );
}
vec2 packDepthToRG( const in float v ) {
if( v <= 0.0 )
return vec2( 0., 0. );
if( v >= 1.0 )
return vec2( 1., 1. );
float vuf;
float gf = modf( v * 256., vuf );
return vec2( vuf * Inv255, gf );
}
float unpackRGBAToDepth( const in vec4 v ) {
return dot( v, UnpackFactors4 );
}
float unpackRGBToDepth( const in vec3 v ) {
return dot( v, UnpackFactors3 );
}
float unpackRGToDepth( const in vec2 v ) {
return v.r * UnpackFactors2.r + v.g * UnpackFactors2.g;
}
vec4 pack2HalfToRGBA( const in vec2 v ) {
vec4 r = vec4( v.x, fract( v.x * 255.0 ), v.y, fract( v.y * 255.0 ) );
return vec4( r.x - r.y / 255.0, r.y, r.z - r.w / 255.0, r.w );
}
vec2 unpackRGBATo2Half( const in vec4 v ) {
return vec2( v.x + ( v.y / 255.0 ), v.z + ( v.w / 255.0 ) );
}
// NOTE: viewZ, the z-coordinate in camera space, is negative for points in front of the camera
float viewZToOrthographicDepth( const in float viewZ, const in float near, const in float far ) {
// -near maps to 0; -far maps to 1
return ( viewZ + near ) / ( near - far );
}
float orthographicDepthToViewZ( const in float depth, const in float near, const in float far ) {
// maps orthographic depth in [ 0, 1 ] to viewZ
return depth * ( near - far ) - near;
}
// NOTE: https://twitter.com/gonnavis/status/1377183786949959682
float viewZToPerspectiveDepth( const in float viewZ, const in float near, const in float far ) {
// -near maps to 0; -far maps to 1
return ( ( near + viewZ ) * far ) / ( ( far - near ) * viewZ );
}
float perspectiveDepthToViewZ( const in float depth, const in float near, const in float far ) {
// maps perspective depth in [ 0, 1 ] to viewZ
return ( near * far ) / ( ( far - near ) * depth - far );
}
`;