我怎样才能改善这个片段着色器:提高Opengl的2.0片段着色器
#ifdef GL_ES
precision mediump float;
#endif
varying vec4 v_fragmentColor;
varying vec2 v_texCoord;
uniform sampler2D u_texture;
uniform vec2 blurSize;
uniform vec4 substract;
void main() {
vec4 sum = vec4(0.0);
sum += texture2D(u_texture, vec2(v_texCoord.x - 4.0 * blurSize.x, v_texCoord.y)) * 0.05;
sum += texture2D(u_texture, vec2(v_texCoord.x - 3.0*blurSize.x, v_texCoord.y)) * 0.09;
sum += texture2D(u_texture, vec2(v_texCoord.x - 2.0*blurSize.x, v_texCoord.y)) * 0.12;
sum += texture2D(u_texture, vec2(v_texCoord.x - blurSize.x, v_texCoord.y)) * 0.15;
sum += texture2D(u_texture, vec2(v_texCoord.x, v_texCoord.y)) * 0.16;
sum += texture2D(u_texture, vec2(v_texCoord.x + blurSize.x, v_texCoord.y)) * 0.15;
sum += texture2D(u_texture, vec2(v_texCoord.x + 2.0*blurSize.x, v_texCoord.y)) * 0.12;
sum += texture2D(u_texture, vec2(v_texCoord.x + 3.0*blurSize.x, v_texCoord.y)) * 0.09;
sum += texture2D(u_texture, vec2(v_texCoord.x + 4.0*blurSize.x, v_texCoord.y)) * 0.05;
gl_FragColor = sum;
}
我用它来模糊的线,所以大多数时间它是融合了相同的颜色。我想让它忽略(留下背景颜色)具有相同周围颜色的像素。我怎么能这样做?