// Copyright 2019 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// This file contains common code used by the image decompression shaders.

// DIM is preprocessor macro set by the build script that determines whether the shader will
// process 1D, 2D or 3D images
#if DIM == 1
#define IMG_TYPE 1DArray
#elif DIM == 2
#define IMG_TYPE 2DArray
#elif DIM == 3
#define IMG_TYPE 3D
#else
#error "Please set the `DIM` preprocessor macro to 1, 2 or 3. Example: glslc -DDIM=2"
#endif

// Concatenates 2 tokens while also performing macro replacement
//
// For example:
//   #define FOO world
//   CONCAT(hello, FOO)
//
// Becomes:
//   helloworld
#define CONCAT_(x, y) x##y          // concatenation
#define CONCAT(x, y) CONCAT_(x, y)  // macro replacement

// Appends the correct image type ("1DArray", "2DArray", or "3D") to x
#define WITH_TYPE(x) CONCAT(x, IMG_TYPE)

// TODO(gregschlom): do we actually use 1DArray images?
ivec2 getPos1DArray(ivec3 pos) { return pos.xz; }
ivec3 getPos2DArray(ivec3 pos) { return pos; }
ivec3 getPos3D(ivec3 pos) { return pos; }