lookup table 256*16 24 bit issue

[delux-soft]

I write this code for 256*16 table, it works fine with 32-bit color but produce wrong result with 24-bit color.

"varying highp vec2 textureCoordinate;\n" + " varying highp vec2 textureCoordinate2; // TODO: This is not used\n" + " \n" + " uniform sampler2D inputImageTexture;\n" + " uniform sampler2D inputImageTexture2; // lookup texture\n" + " \n" + " uniform lowp float intensity;\n" + " \n" + "void main() {" + " highp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);\n" + " \n" + " highp float blueColor = textureColor.b 15.0;\n" + " \n" + " highp vec2 quad1;\n" + " quad1.y = floor(floor(blueColor) / 1.0);\n" + " quad1.x = floor(blueColor) - (quad1.y 16.0);\n" + " \n" + " highp vec2 quad2;\n" + " quad2.y = floor(ceil(blueColor) / 1.0);\n" + " quad2.x = ceil(blueColor) - (quad2.y 16.0);\n" + " \n" + " highp vec2 texPos1;\n" + " texPos1.x = (quad1.x 0.0625) + 0.5/256.0 + ((0.0625 - 1.0/256.0) textureColor.r);\n" + " texPos1.y = (quad1.y 1.0) + 0.5/16.0 + ((1.0 - 1.0/16.0) textureColor.g);\n" + " \n" + " highp vec2 texPos2;\n" + " texPos2.x = (quad2.x 0.0625) + 0.5/256.0 + ((0.0625 - 1.0/256.0) textureColor.r);\n" + " texPos2.y = (quad2.y 1.0) + 0.5/16.0 + ((1.0 - 1.0/16.0) * textureColor.g);\n" + " \n" + " lowp vec4 newColor1 = texture2D(inputImageTexture2, texPos1);\n" + " lowp vec4 newColor2 = texture2D(inputImageTexture2, texPos2);\n" + " \n" + " lowp vec4 newColor = mix(newColor1, newColor2, fract(blueColor));\n" + " gl_FragColor = mix(textureColor, vec4(newColor.rgb, textureColor.w), intensity);\n" + "}"