perspective_camera.cpp

#include "perspective_camera.h"

PerspectiveCamera::PerspectiveCamera( void )
{}

PerspectiveCamera::PerspectiveCamera( const float min_x,
                                        const float max_x,
                                        const float min_y,
                                        const float max_y,
                                        const float distance, //distance to viewport
                                        const glm::ivec2 &resolution,
                                        const glm::vec3 &position,
                                        const glm::vec3 &up_vector,
                                        const glm::vec3 &look_at ) :
        Camera::Camera{ resolution, 
                        position,
                        up_vector,
                        look_at },
        min_x_{ min_x },
        max_x_{ max_x },
        min_y_{ min_y },
        max_y_{ max_y },
        distance_{ distance }
{}

Ray PerspectiveCamera::getWorldSpaceRay( const glm::vec2 &pixel_coord ) const
{
    float width = max_x_ - min_x_;
    float height = max_y_ - min_y_;
              
    glm::vec3 screen_point{ ( pixel_coord[0]+0.5f )/ static_cast< float >( resolution_[0] ) * width + min_x_,
                            ( pixel_coord[1]+0.5f )/ static_cast< float >( resolution_[1] ) * -height + max_y_,
                            -distance_ };

    return Ray{ position_, glm::normalize( onb_.getBasisMatrix() * screen_point ) };
}