Topics

1

Graphics / Conceptualizing "Ghosting" Sprite Movement

« on: August 29, 2014, 07:58:11 pm »

I have an animated sprite of a walking character.  I would like to achieve something similar to Castlevania:SoTN's "ghosting" effect, seen in this gif when the character is falling:

and in this image (to a lesser extent):


I'm thinking of handling it by:
1) drawing the sprite to a rendertexture.  Successive frames would then
2) offset the sprite by whatever camera movement has taken place,
3) doing a color/alpha pass on the existing "ghosted" render texture,
4) rendering the current sprite in it's normal position, and repeating.

Am I overthinking this and should just use a collection of sf::Sprites along with some setColor's, or is the gpu be the best way to go?

2

Graphics / sf::VertexArray: Help Generating Verticies of This Object

« on: August 09, 2014, 02:06:55 am »

I'm trying to create a light source like in this image:


I see the implementation looking something like this, but I'm stuck as to how to achieve the radius fall-off effect.  Generating a full circle is a trivial case, the case where the angle is not a full circle is interesting, and to be clear, the radius fall-off is the most interesting part of this problem.  I'm looking ideally to use a for loop and create this look for an arbitrarily-sized vertex array, thanks.

struct Light : public sf::Drawable {
        Light( );


        sf::Vector2f    position;       // center of the triangle fan
        sf::Vector2f    direction;      // values clamped [-1, 1]
        float                   radius;
        float                   angle;          // equals pi radians in the image
        sf::Color               color;
        sf::VertexArray verticies;      // TriangleFan

        void                    draw( sf::RenderTarget& target, sf::RenderStates states ) const final override { target.draw( verticies, states ); }
        void                    calculateVerticies( );
};

void Light::calculateVerticies( ) {
        // amazing code, wow so good
}

3

Graphics / Trouble changing Text and RectangleShape color with SetColor/SetFillColor

« on: December 24, 2013, 06:29:40 pm »

I have two classes which, for the purpose of this exercise, are defined as follows:

class Editor {
public:
struct editorItem_t {
        sf::RectangleShape                                      rect;
        sf::Text                                                        text;
        editorState_t                                           action;
};
std::list<editorItem_t>                                 editorItems;
}

class Game {
public:
        void Game::EditorMode( const sf::Event& currentEvent );
private:
        Editor editor;
}

Please assume that there is a font loaded and that the sf::Text component is currently writing correctly.  EditorMode is defined as follows, and this is where my problem lies.  I'm using C++11 auto notation, but even without that the color-change statements are not working as intended:

void Game::EditorMode( const sf::Event& currentEvent ) {
        //check to see if any editorItem_t rects were clicked
        if ( currentEvent.type == sf::Event::MouseButtonPressed ) {
                if ( sf::Mouse::isButtonPressed( sf::Mouse::Button::Left ) ) {
                        for ( auto itr = editor.editorItems.begin( ); itr != editor.editorItems.end( ); ++itr ) {
                                if ( itr->rect.getGlobalBounds( ).contains( currentEvent.mouseButton.x, currentEvent.mouseButton.y ) ) {
                                        itr->rect.setFillColor( sf::Color::Blue );      //this isn't working at all
                                        itr->text.setColor( sf::Color::White );     //this isn't working at all
                                        std::cout << "But this statement is working fine!" << std::endl;
                                }
                        }
                }
        }
}

The compiler basically seems to be treating the rect.setFillColor and text.SetColor statements as no-ops and I have no idea how to fix this, any help would be much appreciated.