 uniform vec4 uCrevasPointsY[CREVAS_POINTS_MAXN/4];
 uniform vec4 uCrevasUnitVecsX[CREVAS_POINTS_MAXN/4];
 uniform vec4 uCrevasUnitVecsY[CREVAS_POINTS_MAXN/4];
-uniform int  uCrevasPointsN;
 
 varying vec3 vColor;
 varying vec3 vTextureCoord;

	float directionSign = sign(aCrevasPos);
	int crevasPos4 = crevasPos / 4;
	vec4 mask = vec4(0.0);
	mask[crevasPos - crevasPos4*4] = 1.0;
#endif

	vec4 apux, apuy;

	vec4 shiftx = vec4(0.0);
	vec4 shifty = vec4(0.0);

	for (int i = 0; i < CREVAS_POINTS_MAXN/4; i++) {
		/*
		There are a point A and a line segment PQ.
		Here, calculating `weight` by following:
