three.js/utils/converters/utf8/src/bounds.h

// Copyright 2012 Google Inc. All Rights Reserved.
//
// 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.

#ifndef WEBGL_LOADER_BOUNDS_H_
#define WEBGL_LOADER_BOUNDS_H_

#include <stdio.h>

#include "base.h"

namespace webgl_loader {

// TODO: arbitrary vertex formats.

struct Bounds {
  float mins[8];
  float maxes[8];

  void Clear() {
    for (size_t i = 0; i < 8; ++i) {
      mins[i] = FLT_MAX;
      maxes[i] = -FLT_MAX;
    }
  }

  void EncloseAttrib(const float* attribs) {
    for (size_t i = 0; i < 8; ++i) {
      const float attrib = attribs[i];
      if (mins[i] > attrib) {
        mins[i] = attrib;
      }
      if (maxes[i] < attrib) {
        maxes[i] = attrib;
      }
    }
  }

  void Enclose(const AttribList& attribs) {
    for (size_t i = 0; i < attribs.size(); i += 8) {
      EncloseAttrib(&attribs[i]);
    }
  }

  float UniformScale() const {
    const float x = maxes[0] - mins[0];
    const float y = maxes[1] - mins[1];
    const float z = maxes[2] - mins[2];
    return (x > y)  // TODO: max3
        ? ((x > z) ? x : z)
        : ((y > z) ? y : z);
  }
};

// TODO: make maxPosition et. al. configurable.
struct BoundsParams {
  static BoundsParams FromBounds(const Bounds& bounds) {
    BoundsParams ret;
    const float scale = bounds.UniformScale();
    // Position. Use a uniform scale.
    for (size_t i = 0; i < 3; ++i) {
      const int maxPosition = (1 << 14) - 1;  // 16383;
      ret.mins[i] = bounds.mins[i];
      ret.scales[i] = scale;
      ret.outputMaxes[i] = maxPosition;
      ret.decodeOffsets[i] = maxPosition * bounds.mins[i] / scale;
      ret.decodeScales[i] = scale / maxPosition;
    }
    // TexCoord.
    // TODO: get bounds-dependent texcoords working!
    for (size_t i = 3; i < 5; ++i) {
      // const float texScale = bounds.maxes[i] - bounds.mins[i];
      const int maxTexcoord = (1 << 10) - 1;  // 1023
      ret.mins[i] = 0;  //bounds.mins[i];
      ret.scales[i] = 1;  //texScale;
      ret.outputMaxes[i] = maxTexcoord;
      ret.decodeOffsets[i] = 0;  //maxTexcoord * bounds.mins[i] / texScale;
      ret.decodeScales[i] = 1.0f / maxTexcoord;  // texScale / maxTexcoord;
    }
    // Normal. Always uniform range.
    for (size_t i = 5; i < 8; ++i) {
      ret.mins[i] = -1;
      ret.scales[i] = 2.f;
      ret.outputMaxes[i] = (1 << 10) - 1;  // 1023
      ret.decodeOffsets[i] = 1 - (1 << 9);  // -511
      ret.decodeScales[i] = 1.0 / 511;
    }
    return ret;
  }

  void DumpJson(FILE* out = stdout) {
    // TODO: use JsonSink.
    fputs("{\n", out);
    fprintf(out, "    \"decodeOffsets\": [%d,%d,%d,%d,%d,%d,%d,%d],\n",
            decodeOffsets[0], decodeOffsets[1], decodeOffsets[2],
            decodeOffsets[3], decodeOffsets[4], decodeOffsets[5],
            decodeOffsets[6], decodeOffsets[7]);
    fprintf(out, "    \"decodeScales\": [%f,%f,%f,%f,%f,%f,%f,%f]\n",
            decodeScales[0], decodeScales[1], decodeScales[2], decodeScales[3],
            decodeScales[4], decodeScales[5], decodeScales[6], decodeScales[7]);
    fputs("  }", out);
  }

  float mins[8];
  float scales[8];
  int outputMaxes[8];
  int decodeOffsets[8];
  float decodeScales[8];
};

}  // namespace webgl_loader

#endif  // WEBGL_LOADER_BOUNDS_H_