${shadersInterpolation(this, 'dataCoordinates', 'dataValue', 'gradient')}源碼解析

`
void texture3d(in ivec3 dataCoordinates, out vec4 dataValue, out int offset){
  float textureSizeF = float(uTextureSize);
  int voxelsPerTexture = uTextureSize*uTextureSize;

  int index = dataCoordinates.x
            + dataCoordinates.y * uDataDimensions.x
            + dataCoordinates.z * uDataDimensions.y * uDataDimensions.x;
  
  // dividing an integer by an integer will give you an integer result, rounded down
  // can not get float numbers to work :(
  int packedIndex = index/uPackedPerPixel;
  offset = index - uPackedPerPixel*packedIndex;

  // Map data index to right sampler2D texture
  int textureIndex = packedIndex/voxelsPerTexture;
  int inTextureIndex = packedIndex - voxelsPerTexture*textureIndex;

  // Get row and column in the texture
  int rowIndex = inTextureIndex/uTextureSize;
  float rowIndexF = float(rowIndex);
  float colIndex = float(inTextureIndex - uTextureSize * rowIndex);

  // Map row and column to uv
  vec2 uv = vec2(0,0);
  uv.x = (0.5 + colIndex) / textureSizeF;
  uv.y = 1. - (0.5 + rowIndexF) / textureSizeF;

  float textureIndexF = float(textureIndex);
  dataValue = vec4(0.) +  
      step( abs( textureIndexF - 0.0 ), 0.0 ) * texture2D(uTextureContainer[0], uv) +
      step( abs( textureIndexF - 1.0 ), 0.0 ) * texture2D(uTextureContainer[1], uv) +
      step( abs( textureIndexF - 2.0 ), 0.0 ) * texture2D(uTextureContainer[2], uv) +
      step( abs( textureIndexF - 3.0 ), 0.0 ) * texture2D(uTextureContainer[3], uv) +
      step( abs( textureIndexF - 4.0 ), 0.0 ) * texture2D(uTextureContainer[4], uv) +
      step( abs( textureIndexF - 5.0 ), 0.0 ) * texture2D(uTextureContainer[5], uv) +
      step( abs( textureIndexF - 6.0 ), 0.0 ) * texture2D(uTextureContainer[6], uv);
}
void uInt8(in float r, out float value){
  value = r * 255.;
}
void unpack(in vec4 packedData, in int offset, out vec4 unpackedData){
	float floatedOffset = float(offset);
	float floatedOffsetSquared = floatedOffset * floatedOffset;
	uInt8(
	  step( floatedOffsetSquared , 0.0 ) * packedData.r +
	  step( floatedOffsetSquared - 2. * floatedOffset + 1., 0.0 ) * packedData.g +
	  step( floatedOffsetSquared - 2. * 2. *  floatedOffset + 4., 0.0 ) * packedData.b +
	  step( floatedOffsetSquared - 2. * 3. *  floatedOffset + 9., 0.0 ) * packedData.a,unpackedData.x);
}
void interpolationIdentity(in vec3 currentVoxel, out vec4 dataValue){
  // lower bound
  vec3 rcurrentVoxel = vec3(floor(currentVoxel.x + 0.5 ), floor(currentVoxel.y + 0.5 ), floor(currentVoxel.z + 0.5 ));
  ivec3 voxel = ivec3(int(rcurrentVoxel.x), int(rcurrentVoxel.y), int(rcurrentVoxel.z));

  vec4 tmp = vec4(0., 0., 0., 0.);
  int offset = 0;
  texture3d(voxel,tmp,offset)
  unpack(tmp, offset, dataValue);
}
`