How to avoid extra calculations in fragment shader - glsl

Question

im trying to fix this shader. the effects is a radial blur around a point position, passing from the cpu in a array. The calculations works fine for each point and generates de effect, but as you can see in this picture, for each loop the shader keep generate samples, and i dont know how to avoid. i only want the blur for each point in the array
#version 150
in vec2 varyingtexcoord;
uniform sampler2DRect tex0;
uniform int size;
float exposure = 0.79;
float decay = 0.9;
float density = .9;
float weight = .1;
int samples = 25;
out vec4 fragColor;
const int MAX_SAMPLES = 25;
const int N = 3;
uniform vec2 ligthPos [N];
int a = 1;
vec4 halo(vec2 pos){
float illuminationDecay = 1.2;
vec2 texCoord = varyingtexcoord;
vec2 current = pos.xy;
vec2 deltaTextCoord = texCoord - current;
deltaTextCoord *= 1.0 / float(samples) * density;
vec4 color = texture(tex0, texCoord);
for(int i=0; i < MAX_SAMPLES; i++){
texCoord -= deltaTextCoord;
vec4 sample = texture(tex0, texCoord);
sample *= illuminationDecay * weight;
color += sample;
illuminationDecay *= decay;
}
return color;
}
void main(){
vec4 accum = vec4(0.0);
for(int e = 0; e < N;e++){
vec2 current =ligthPos[e];
accum += halo(current);
}
fragColor = (accum) * exposure;
}
this is what happen: