o3de/Code/Editor/GridUtils.h

/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */


#ifndef CRYINCLUDE_EDITOR_GRIDUTILS_H
#define CRYINCLUDE_EDITOR_GRIDUTILS_H
#pragma once


namespace GridUtils
{
    template <typename F>
    inline void IterateGrid(F& f, const float minPixelsPerTick, float zoomX, float originX, float fps, int left, int right)
    {
        float pixelsPerSecond = zoomX;
        float pixelsPerFrame = pixelsPerSecond / fps;
        float framesPerTick = ceil(minPixelsPerTick / pixelsPerFrame);
        float scale = 1;
        bool foundScale = false;
        int numIters = 0;
        for (float OOM = 1; !foundScale; OOM *= 10)
        {
            float scales[] = {1, 2, 5};
            for (int scaleIndex = 0; !foundScale && scaleIndex < sizeof(scales) / sizeof(scales[0]); ++scaleIndex)
            {
                scale = scales[scaleIndex] * OOM;
                if (framesPerTick <= scale + 0.1f)
                {
                    framesPerTick = scale;
                    foundScale = true;
                    if (numIters++ > 1000)
                    {
                        break;
                    }
                }
            }
            if (numIters++ > 1000)
            {
                break;
            }
        }
        float pixelsPerTick = pixelsPerFrame * framesPerTick;
        float timeAtLeft = -left / zoomX + originX;
        float frameAtLeft = ceil(timeAtLeft * fps / framesPerTick) * framesPerTick;
        float firstTick = floor((frameAtLeft / fps - originX) * zoomX + 0.5f) + left;
        int frame = int(frameAtLeft);
        int lockupPreventionCounter = 10000;
        for (float tickX = firstTick; tickX < right && lockupPreventionCounter >= 0; tickX += pixelsPerTick, --lockupPreventionCounter)
        {
            f(frame, aznumeric_cast<int>(tickX));

            frame += int(framesPerTick);
        }
    }
}

#endif // CRYINCLUDE_EDITOR_GRIDUTILS_H