将GPUImageAlphaBlendFilter.m中的“gl_FragColor = vec4(mix(textureColor.rgb, textureColor2.rgb, textureColor2.a * mixturePercent), textureColor.a);”（老sdk有一处，新sdk有两处）替换为：“if (textureColor2.a == 0.0) {
gl_FragColor = textureColor;
} else {
gl_FragColor = vec4(mix(textureColor.rgb, textureColor2.rgb / textureColor2.a,mixturePercent * textureColor2.a), textureColor.a);
}”即可。