three
Version:
JavaScript 3D library
187 lines (102 loc) • 3.88 kB
JavaScript
export default /* glsl */`
// These shader functions convert between the UV coordinates of a single face of
// a cubemap, the 0-5 integer index of a cube face, and the direction vector for
// sampling a textureCube (not generally normalized ).
float getFace( vec3 direction ) {
vec3 absDirection = abs( direction );
float face = - 1.0;
if ( absDirection.x > absDirection.z ) {
if ( absDirection.x > absDirection.y )
face = direction.x > 0.0 ? 0.0 : 3.0;
else
face = direction.y > 0.0 ? 1.0 : 4.0;
} else {
if ( absDirection.z > absDirection.y )
face = direction.z > 0.0 ? 2.0 : 5.0;
else
face = direction.y > 0.0 ? 1.0 : 4.0;
}
return face;
}
// RH coordinate system; PMREM face-indexing convention
vec2 getUV( vec3 direction, float face ) {
vec2 uv;
if ( face == 0.0 ) {
uv = vec2( direction.z, direction.y ) / abs( direction.x ); // pos x
} else if ( face == 1.0 ) {
uv = vec2( - direction.x, - direction.z ) / abs( direction.y ); // pos y
} else if ( face == 2.0 ) {
uv = vec2( - direction.x, direction.y ) / abs( direction.z ); // pos z
} else if ( face == 3.0 ) {
uv = vec2( - direction.z, direction.y ) / abs( direction.x ); // neg x
} else if ( face == 4.0 ) {
uv = vec2( - direction.x, direction.z ) / abs( direction.y ); // neg y
} else {
uv = vec2( direction.x, direction.y ) / abs( direction.z ); // neg z
}
return 0.5 * ( uv + 1.0 );
}
vec3 bilinearCubeUV( sampler2D envMap, vec3 direction, float mipInt ) {
float face = getFace( direction );
float filterInt = max( cubeUV_minMipLevel - mipInt, 0.0 );
mipInt = max( mipInt, cubeUV_minMipLevel );
float faceSize = exp2( mipInt );
highp vec2 uv = getUV( direction, face ) * ( faceSize - 2.0 ) + 1.0; // #25071
if ( face > 2.0 ) {
uv.y += faceSize;
face -= 3.0;
}
uv.x += face * faceSize;
uv.x += filterInt * 3.0 * cubeUV_minTileSize;
uv.y += 4.0 * ( exp2( CUBEUV_MAX_MIP ) - faceSize );
uv.x *= CUBEUV_TEXEL_WIDTH;
uv.y *= CUBEUV_TEXEL_HEIGHT;
return texture2DGradEXT( envMap, uv, vec2( 0.0 ), vec2( 0.0 ) ).rgb; // disable anisotropic filtering
return texture2D( envMap, uv ).rgb;
}
// These defines must match with PMREMGenerator
float roughnessToMip( float roughness ) {
float mip = 0.0;
if ( roughness >= cubeUV_r1 ) {
mip = ( cubeUV_r0 - roughness ) * ( cubeUV_m1 - cubeUV_m0 ) / ( cubeUV_r0 - cubeUV_r1 ) + cubeUV_m0;
} else if ( roughness >= cubeUV_r4 ) {
mip = ( cubeUV_r1 - roughness ) * ( cubeUV_m4 - cubeUV_m1 ) / ( cubeUV_r1 - cubeUV_r4 ) + cubeUV_m1;
} else if ( roughness >= cubeUV_r5 ) {
mip = ( cubeUV_r4 - roughness ) * ( cubeUV_m5 - cubeUV_m4 ) / ( cubeUV_r4 - cubeUV_r5 ) + cubeUV_m4;
} else if ( roughness >= cubeUV_r6 ) {
mip = ( cubeUV_r5 - roughness ) * ( cubeUV_m6 - cubeUV_m5 ) / ( cubeUV_r5 - cubeUV_r6 ) + cubeUV_m5;
} else {
mip = - 2.0 * log2( 1.16 * roughness ); // 1.16 = 1.79^0.25
}
return mip;
}
vec4 textureCubeUV( sampler2D envMap, vec3 sampleDir, float roughness ) {
float mip = clamp( roughnessToMip( roughness ), cubeUV_m0, CUBEUV_MAX_MIP );
float mipF = fract( mip );
float mipInt = floor( mip );
vec3 color0 = bilinearCubeUV( envMap, sampleDir, mipInt );
if ( mipF == 0.0 ) {
return vec4( color0, 1.0 );
} else {
vec3 color1 = bilinearCubeUV( envMap, sampleDir, mipInt + 1.0 );
return vec4( mix( color0, color1, mipF ), 1.0 );
}
}
`;