#if USE_MAPPING_0
varying vec2 vUv0;
#endif

#if USE_MAPPING_1
varying vec2 vUv1;
#endif

#if USE_MAPPING_2
varying vec2 vUv2;
#endif

// ... etc until USE_MAPPING_8

#if TEXTURES_ARRAY_SIZE > 0
uniform sampler2D layersTexture[TEXTURES_ARRAY_SIZE];
uniform int layersMapping[TEXTURES_ARRAY_SIZE];
uniform float layersOpacity[TEXTURES_ARRAY_SIZE];
uniform bool layersIsPremult[TEXTURES_ARRAY_SIZE];
uniform int layersMergeOp[TEXTURES_ARRAY_SIZE];
uniform bool layersTransparent[TEXTURES_ARRAY_SIZE];
uniform bool layersIsMatte[TEXTURES_ARRAY_SIZE];
uniform vec2 layersRepeat[TEXTURES_ARRAY_SIZE];
#endif

// unrolled UV getter
vec2 getUv(int uvSetNumber) {
    #if USE_MAPPING_0
    if (uvSetNumber == 0) {
        return vUv0;
    }
    #endif

    #if USE_MAPPING_1
    if (uvSetNumber == 1) {
        return vUv1;
    }
    #endif

    // etc...
}

#if USE_TEXTURE_0
uniform sampler2D sampler0;
#endif

#if USE_TEXTURE_1
uniform sampler2D sampler1;
#endif

// ...

vec4 getTextureSample(int textureIndex, vec2 uv) {
    #if USE_TEXTURE_0
    if (textureIndex == 0) {
        return texture2D(sampler0, uv);
    }
    #endif

    #if USE_TEXTURE_1
    if (textureIndex == 1) {
        return texture2D(sampler1, uv);
    }
    #endif

    // etc...
}