Camera

#include "Camera.cuh"

__device__
void Camera::beginFrame()
{
    double x = -aspect;
    double y = +1;

    Vector corner = Vector(x, y, 1);
    Vector center = Vector(0, 0, 1);

    double lenXY = (corner - center).length();
    double wantedLength = tan(toRadians(fov / 2));

    double scaling = wantedLength / lenXY;

    x *= scaling;
    y *= scaling;

    this->upLeft = Vector(x, y, 1);
    this->upRight = Vector(-x, y, 1);
    this->downLeft = Vector(x, -y, 1);

    Matrix rotation = rotationAroundZ(toRadians(roll))
                    * rotationAroundX(toRadians(pitch))
                    * rotationAroundY(toRadians(yaw));
    upLeft *= rotation;
    upRight *= rotation;
    downLeft *= rotation;

    rightDir = Vector(-1, 0, 0) * rotation;
    upDir    = Vector(0, -1, 0) * rotation;
    frontDir = Vector(0, 0, -1) * rotation;

    upLeft += pos;
    upRight += pos;
    downLeft += pos;
}

__device__
Ray Camera::getScreenRay(double x, double y)
{
    Ray result; // A, B -     C = A + (B - A) * x
    result.start = this->pos;
    Vector target = upLeft +
        (upRight - upLeft) * (x / (double) RES_X) +
        (downLeft - upLeft) * (y / (double) RES_Y);

    // A - camera; B = target
    result.dir = target - this->pos;

    result.dir.normalize();

    return result;
}

__device__
void Camera::move(double dx, double dz)
{
    pos += dx * rightDir;
    pos += dz * frontDir;
}