evs/app/ConfigManager.h

/*
 * Copyright (C) 2017 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.
 */
#ifndef CONFIG_MANAGER_H
#define CONFIG_MANAGER_H

#include <vector>
#include <string>


class ConfigManager {
public:
    struct CameraInfo {
        std::string cameraId = "";  // The name of the camera from the point of view of the HAL
        std::string function = "";  // The expected use for this camera ("reverse", "left", "right")
        float position[3] = {0};    // x, y, z -> right, fwd, up in the units of car space
        float yaw   = 0;    // radians positive to the left (right hand rule about global z axis)
        float pitch = 0;    // positive upward (ie: right hand rule about local x axis)
        float hfov  = 0;    // radians
        float vfov  = 0;    // radians
    };

    bool initialize(const char* configFileName);

    // World space dimensions of the car
    float getCarWidth() const   { return mCarWidth; };
    float getCarLength() const  { return mWheelBase + mFrontExtent + mRearExtent; };
    float getWheelBase() const  { return mWheelBase; };

    // Car space (world space centered on the rear axel) edges of the car
    float getFrontLocation() const  { return mWheelBase + mFrontExtent; };
    float getRearLocation() const   { return -mRearExtent; };
    float getRightLocation() const  { return mCarWidth*0.5f; };
    float getLeftLocation() const   { return -mCarWidth*0.5f; };

    // Where are the edges of the top down display in car space?
    float getDisplayTopLocation() const {
        // From the rear axel (origin) to the front bumper, and then beyond by the front range
        return mWheelBase + mFrontExtent + mFrontRangeInCarSpace;
    };
    float getDisplayBottomLocation() const {
        // From the rear axel (origin) to the back bumper, and then beyond by the back range
        return -mRearExtent - mRearRangeInCarSpace;
    };
    float getDisplayRightLocation(float aspectRatio) const   {
        // Given the display aspect ratio (width over height), how far can we see to the right?
        return (getDisplayTopLocation() - getDisplayBottomLocation()) * 0.5f * aspectRatio;
    };
    float getDisplayLeftLocation(float aspectRatio) const {
        // Given the display aspect ratio (width over height), how far can we see to the left?
        return -getDisplayRightLocation(aspectRatio);
    };

    // At which texel (vertically in the image) are the front and rear bumpers of the car?
    float carGraphicFrontPixel() const      { return mCarGraphicFrontPixel; };
    float carGraphicRearPixel() const       { return mCarGraphicRearPixel; };

    const std::vector<CameraInfo>& getCameras() const   { return mCameras; };

private:
    // Camera information
    std::vector<CameraInfo> mCameras;

    // Car body information (assumes front wheel steering and origin at center of rear axel)
    // Note that units aren't specified and don't matter as long as all length units are consistent
    // within the JSON file from which we parse.  That is, if everything is in meters, that's fine.
    // Everything in mm?  That's fine too.
    float mCarWidth;
    float mWheelBase;
    float mFrontExtent;
    float mRearExtent;

    // Display information
    float    mFrontRangeInCarSpace;     // How far the display extends in front of the car
    float    mRearRangeInCarSpace;      // How far the display extends behind the car

    // Top view car image information
    float mCarGraphicFrontPixel;    // How many pixels from the top of the image does the car start
    float mCarGraphicRearPixel;     // How many pixels from the top of the image does the car end
};

#endif // CONFIG_MANAGER_H