game/sdlpp/sdlpp_circlecolider.cpp

#include "sdlpp_circlecolider.hpp"
#include "sdlpp_geometry.hpp"

namespace SDLPP {
CircleColider::CircleColider( double x, double y, double rad )
        : CircleColider( { x, y }, rad ) {}

CircleColider::CircleColider( const Vec2D< double > &center, double rad )
        : CollisionPolygon( center ), original_rad( rad ) {}
CircleColider::CircleColider( double x, double y, double rad, uint64_t id )
        : CircleColider( { x, y }, rad, id ) {}
CircleColider::CircleColider( const Vec2D< double > &center, double rad,
                              uint64_t id )
        : CircleColider( center, rad ) {
    _id = id;
}

bool CircleColider::colidesWith( const SDLPP::CollisionPolygon &other ) const {
    if ( other.isCircle() ) {
        /* check if distance of centers is lower than radiuses added together */
        int otherRad =
            dynamic_cast< const SDLPP::CircleColider & >( other ).getRadius();
        int thisRad = getRadius();
        int totalDist = otherRad + thisRad;
        int xdiff = other.getX() - getX();
        int ydiff = other.getY() - getY();
        return ( xdiff * xdiff + ydiff * ydiff ) <= totalDist * totalDist;
    } else if ( other.isInfinite() ) {
        return infinityIntersection( other, *this );
    }
    /* other is not a circle */
    int rad = getRadius();
    for ( auto &line : other.getLines() ) {
        auto distance = pointLineDistance( position, line );
        if ( distance * distance <= rad * rad )
            return true;
    }
    return false;
}

bool CircleColider::isCircle() const {
    return true;
}
int CircleColider::topmost() const {
    return getY() - rad_;
}
int CircleColider::bottommost() const {
    return getY() + rad_;
}
int CircleColider::leftmost() const {
    return getX() - rad_;
}
int CircleColider::rightmost() const {
    return getX() + rad_;
}

void CircleColider::updateCollision( int x, int y, int w, int h, uint64_t id ) {
    position = Vec2D< int >( original.getX() * w + x, original.getY() * h + y );
    rad_ = original_rad * w;
    if ( _id == static_cast< uint64_t >( -1 ) )
        _id = id;
}

void CircleColider::render( Renderer &renderer, const SDL_Color &color,
                            const SDL_Color &outline_color ) {
    std::vector< int > rect = { leftmost(), topmost(), rightmost(),
                                bottommost() };
    auto center_x = getX();
    auto center_y = getY();
    auto radsq = rad_ * rad_;
    for ( int i = rect[0]; i <= rect[2]; i++ ) {
        auto xdiff = center_x - i;
        auto xdist = xdiff * xdiff;
        auto allowed_rad = sqrt( radsq - xdist );
        SDL_SetRenderDrawColor( renderer.getRendererPtr(), color.r, color.g,
                                color.b, color.a );
        SDL_RenderDrawLine( renderer.getRendererPtr(), i,
                            center_y - allowed_rad, i, center_y + allowed_rad );
        SDL_SetRenderDrawColor( renderer.getRendererPtr(), outline_color.r,
                                outline_color.g, outline_color.b,
                                outline_color.a );
        SDL_RenderDrawLine( renderer.getRendererPtr(), i,
                            center_y - allowed_rad, i,
                            center_y - allowed_rad + 2 );
        SDL_RenderDrawLine( renderer.getRendererPtr(), i,
                            center_y + allowed_rad, i,
                            center_y + allowed_rad - 2 );
    }
}

void CircleColider::render( Renderer &renderer, const SDL_Color &color ) {
    auto input_color = color;
    auto outline_color = color;
    input_color.a = 0x40;
    outline_color.a = 0x80;
    render( renderer, input_color, outline_color );
}

void CircleColider::render( Renderer &renderer ) {
    render( renderer, sdl_color, sdl_outline );
}

int CircleColider::getRadius() const {
    return rad_;
}

std::shared_ptr< CollisionPolygon > CircleColider::copySelf() {
    return std::make_shared< CircleColider >( *this );
}

std::vector< Line< int > > CircleColider::getLines() const {
    return {};
}
} // namespace SDLPP