/*
 * Copyright (C) 2012 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.
 */

#include "ip.rsh"
#pragma rs_fp_relaxed


static rs_allocation gCube;
static int4 gDims;
static int4 gCoordMul;


void setCube(rs_allocation c) {
    gCube = c;
    gDims.x = rsAllocationGetDimX(gCube);
    gDims.y = rsAllocationGetDimY(gCube);
    gDims.z = rsAllocationGetDimZ(gCube);
    gDims.w = 0;

    float4 m = (float4)(1.f / 255.f) * convert_float4(gDims - 1);
    gCoordMul = convert_int4(m * (float4)0x10000);
}

uchar4 RS_KERNEL root(uchar4 in) {
    int4 baseCoord = convert_int4(in) * gCoordMul;
    int4 coord1 = baseCoord >> (int4)16;
    int4 coord2 = min(coord1 + 1, gDims - 1);

    int4 weight2 = baseCoord & 0xffff;
    int4 weight1 = (int4)0x10000 - weight2;

    uint4 v000 = convert_uint4(rsGetElementAt_uchar4(gCube, coord1.x, coord1.y, coord1.z));
    uint4 v100 = convert_uint4(rsGetElementAt_uchar4(gCube, coord2.x, coord1.y, coord1.z));
    uint4 v010 = convert_uint4(rsGetElementAt_uchar4(gCube, coord1.x, coord2.y, coord1.z));
    uint4 v110 = convert_uint4(rsGetElementAt_uchar4(gCube, coord2.x, coord2.y, coord1.z));
    uint4 v001 = convert_uint4(rsGetElementAt_uchar4(gCube, coord1.x, coord1.y, coord2.z));
    uint4 v101 = convert_uint4(rsGetElementAt_uchar4(gCube, coord2.x, coord1.y, coord2.z));
    uint4 v011 = convert_uint4(rsGetElementAt_uchar4(gCube, coord1.x, coord2.y, coord2.z));
    uint4 v111 = convert_uint4(rsGetElementAt_uchar4(gCube, coord2.x, coord2.y, coord2.z));

    uint4 yz00 = ((v000 * weight1.x) + (v100 * weight2.x)) >> (uint4)8;
    uint4 yz10 = ((v010 * weight1.x) + (v110 * weight2.x)) >> (uint4)8;
    uint4 yz01 = ((v001 * weight1.x) + (v101 * weight2.x)) >> (uint4)8;
    uint4 yz11 = ((v011 * weight1.x) + (v111 * weight2.x)) >> (uint4)8;

    uint4 z0 = ((yz00 * weight1.y) + (yz10 * weight2.y)) >> (uint4)16;
    uint4 z1 = ((yz01 * weight1.y) + (yz11 * weight2.y)) >> (uint4)16;

    uint4 v = ((z0 * weight1.z) + (z1 * weight2.z)) >> (uint4)16;
    uint4 v2 = (v + 0x7f) >> (uint4)8;

    uchar4 o = convert_uchar4(v2);
    o.a = 0xff;
    return o;
}

