translational shader update

js/simulation/function/EM/shaders/positionCalcShader.js

@@ -5,13 +5,13 @@ uniform float u_dt;
 
 uniform sampler2D u_velocity;
 uniform sampler2D u_lastTranslation;
-uniform sampler2D u_fixed;
+uniform sampler2D u_mass;
 
 void main(){
     vec2 fragCoord = gl_FragCoord.xy;
     vec2 scaledFragCoord = fragCoord/u_textureDim;
 
-    float isFixed = texture2D(u_fixed, scaledFragCoord).x;
+    float isFixed = texture2D(u_mass, scaledFragCoord).y;
     if (isFixed < 0.0 || isFixed == 1.0){//no cell or is fixed
         gl_FragColor = vec4(0, 0, 0, 0);
         return;