export default /* glsl */`
#ifdef USE_SKINNING

	uniform mat4 bindMatrix;
	uniform mat4 bindMatrixInverse;

	uniform highp sampler2D boneTexture;
	uniform int boneTextureSize;

	mat4 getBoneMatrix( const in float i ) {

		float j = i * 4.0;
		float x = mod( j, float( boneTextureSize ) );
		float y = floor( j / float( boneTextureSize ) );

		float dx = 1.0 / float( boneTextureSize );
		float dy = 1.0 / float( boneTextureSize );

		y = dy * ( y + 0.5 );

		vec4 v1 = texture2D( boneTexture, vec2( dx * ( x + 0.5 ), y ) );
		vec4 v2 = texture2D( boneTexture, vec2( dx * ( x + 1.5 ), y ) );
		vec4 v3 = texture2D( boneTexture, vec2( dx * ( x + 2.5 ), y ) );
		vec4 v4 = texture2D( boneTexture, vec2( dx * ( x + 3.5 ), y ) );

		mat4 bone = mat4( v1, v2, v3, v4 );

		return bone;

	}

#endif
`;