Camera.cpp

// ======================================================================== //
// Copyright 2018-2020 Ingo Wald                                            //
//                                                                          //
// 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.                                           //
// ======================================================================== //

/*
* Adapted by Alper Sahistan 
* 03/17/2023
*/
#include "Camera.h"

namespace deltaVis
{
vec3f Camera::getFrom() const
{
    return position;
}

vec3f Camera::getAt() const
{
    return position - frame.vz;
}

vec3f Camera::getUp() const
{
    return frame.vy;
}

// void Camera::digestInto(SimpleCamera &easy)
// {
//   easy.lens.center = position;
//   easy.lens.radius = 0.f;
//   easy.lens.du     = frame.vx;
//   easy.lens.dv     = frame.vy;

//   const float minFocalDistance
//     = max(computeStableEpsilon(position),
//                computeStableEpsilon(frame.vx));

//   /*
//     tan(fov/2) = (height/2) / dist
//     -> height = 2*tan(fov/2)*dist
//   */
//   float screen_height
//     = 2.f*tanf(fovyInDegrees/2 * (float)M_PI/180.f)
//     * max(minFocalDistance,focalDistance);
//   easy.screen.vertical   = screen_height * frame.vy;
//   easy.screen.horizontal = screen_height * aspect * frame.vx;
//   easy.screen.lower_left
//     = //easy.lens.center
//     /* NEGATIVE z axis! */
//     - max(minFocalDistance,focalDistance) * frame.vz
//     - 0.5f * easy.screen.vertical
//     - 0.5f * easy.screen.horizontal;

//   easy.lastModified = getCurrentTime();
// }

void Camera::setFovy(const float fovy)
{
    this->fovyInDegrees = fovy;
}

void Camera::setAspect(const float aspect)
{
    this->aspect = aspect;
}

void Camera::setFocalDistance(float focalDistance)
{
    this->focalDistance = focalDistance;
}

/*! tilt the frame around the z axis such that the y axis is "facing upwards" */
void Camera::forceUpFrame()
{
    // frame.vz remains unchanged
    if (fabsf(dot(frame.vz, upVector)) < 1e-6f)
        // looking along upvector; not much we can do here ...
        return;
    frame.vx = normalize(cross(upVector, frame.vz));
    frame.vy = normalize(cross(frame.vz, frame.vx));
}

void Camera::setOrientation(/* camera origin    : */ const vec3f &origin,
                            /* point of interest: */ const vec3f &interest,
                            /* up-vector        : */ const vec3f &up,
                            /* fovy, in degrees : */ float fovyInDegrees,
                            /* set focal dist?  : */ bool setFocalDistance)
{
    this->fovyInDegrees = fovyInDegrees;
    position = origin;
    upVector = up;
    frame.vz = (interest == origin)
                   ? vec3f(0, 0, 1)
                   : /* negative because we use NEGATIZE z axis */ -normalize(interest - origin);
    frame.vx = cross(up, frame.vz);
    if (dot(frame.vx, frame.vx) < 1e-8f)
        frame.vx = vec3f(0, 1, 0);
    else
        frame.vx = normalize(frame.vx);
    // frame.vx
    //   = (fabs(dot(up,frame.vz)) < 1e-6f)
    //   ? vec3f(0,1,0)
    //   : normalize(cross(up,frame.vz));
    frame.vy = normalize(cross(frame.vz, frame.vx));
    poiDistance = length(interest - origin);
    if (setFocalDistance)
        focalDistance = poiDistance;
    forceUpFrame();
}
}