Messages

31

Graphics / How do I layer a sprite onto a bg?

« on: September 15, 2010, 07:41:47 am »

I think the function you need is:

Code: [Select]

void sf::Image::CreateMaskFromColor(Color ColorKey, Uint8 Alpha = 0)

32

SFML projects / Lightning

« on: September 14, 2010, 07:44:16 pm »

You can find a short video clip here: http://welzien.se/misc/lightning.avi

33

SFML projects / Lightning

« on: September 13, 2010, 09:50:30 pm »

I'm going to need a force field in future project and since I suck at making graphics, I decided to make a simple class that draws lightning (not a lightning rod  

I thought I'd share the code incase someone else need some lightning.

Code: [Select]

#include <SFML/Graphics.hpp>
#include <vector>

class Lightning : public sf::Drawable
{
  public:
               Lightning(unsigned long noSegments, float thickness = 1.0f, sf::Color fadeColor = sf::Color(0, 0, 0))
                 : noSegments(noSegments), thickness(thickness), fadeColor(fadeColor)                                {segments.reserve(noSegments);}
  void         generate ();
  void         setSize  (float width, float height)                                                                  {size.x = width; size.y = height;}
  virtual void Render   (sf::RenderTarget& target, sf::Renderer& renderer) const;

  private:
  unsigned long      noSegments;
  float              thickness;
  sf::Color          fadeColor; // Outer color of the lightning
  std::vector<float> segments;  // Contains the x-position of each segment (-1.0 - +1.0), multiply with width to get final position
  sf::Vector2f       size;      // Size of the lightning
};

void Lightning::generate()
{
  sf::Vector2f start;
  sf::Vector2f end(0.0f, 0.0f);

  segments.clear();

  segments.push_back(0.0f); // The start point of the lightning is centered

  for(unsigned long c = 1; c < noSegments - 1; ++c)
    segments.push_back(sf::Randomizer::Random(-1.0f, 1.0f));

  segments.push_back(0.0f); // The end point of the lightning is also centered
}

void Lightning::Render(sf::RenderTarget& target, sf::Renderer& renderer) const
{
  sf::Vector2f start, end;
  sf::Color color, colorDifference, colorStep;

  // If the thickness is 1.0 then draw using only the main color. Otherwise calculate the amount to fade the fade color each iteration
  if(thickness == 1.0f)
    color = GetColor();
  else
  {
    color = fadeColor;
 
    // sf::Color doesn't provide the minus or division operators, so we'll have to make the calculations component by component
    colorDifference = sf::Color(GetColor().r - fadeColor.r,
                                GetColor().g - fadeColor.g,
                                GetColor().b - fadeColor.b,
                                GetColor().a - fadeColor.a);
    colorStep = sf::Color(colorDifference.r / static_cast<sf::Uint8> (thickness - 1.0f),
                          colorDifference.g / static_cast<sf::Uint8> (thickness - 1.0f),
                          colorDifference.b / static_cast<sf::Uint8> (thickness - 1.0f),
                          colorDifference.a / static_cast<sf::Uint8> (thickness - 1.0f)); // Increase the fade color by this each iteration.
  }

  float segmentHeight = size.y / (noSegments - 1.0f);
  float halfWidth = size.x / 2;
  float halfThickness = thickness / 2;

  // Draw multiple lightnings, decreasing the thinkness by 1.0 until we reach thickness 1.0 (or less)
  for(float t = thickness; t >= 1.0f; --t, color += colorStep)
    for(unsigned long c = 0; c < noSegments - 1; ++c)
    {
      start.x = segments[c]     * (halfWidth - halfThickness) + halfWidth ; start.y = segmentHeight * c;
        end.x = segments[c + 1] * (halfWidth - halfThickness)  + halfWidth;   end.y = segmentHeight * (c + 1);
      sf::Shape line = sf::Shape::Line(start, end, t, color);
      target.Draw(line);
    }
}

int main()
{
  sf::RenderWindow window(sf::VideoMode(800, 600), "Lightning test");
  sf::Event evnt;
  bool paused=false;
  Lightning lightning(15, 3.0f, sf::Color::Blue);
  lightning.SetPosition(0.0f, 0.0f);
  lightning.setSize(15.0f, 150.0f);
  lightning.SetColor(sf::Color::White);

  while(window.IsOpened())
  {
    while(window.GetEvent(evnt))
    {
      if(evnt.Type == sf::Event::Closed)
        window.Close();
      if(evnt.Type == sf::Event::KeyPressed && evnt.Key.Code == sf::Key::Escape)
        window.Close();
      if(evnt.Type == sf::Event::KeyPressed && evnt.Key.Code == sf::Key::Space)
        paused=true;
      if(evnt.Type == sf::Event::KeyReleased && evnt.Key.Code == sf::Key::Space)
        paused=false;
    }

    if(!paused)
    {
      window.Clear();

      lightning.generate();
      window.Draw(lightning);

      window.Display();
    }
  }
 
  return EXIT_SUCCESS;
}

I've included a simple main() to test it. Hold SPACE to pause, ESCAPE to quit.

The corners don't look good if the size and/or thinkness gets to large. The start and end points of the lightning are fixed. But it shouldn't be too hard to change that if you need eg. a lightning gun.

I've only tried it with SFML2.

edit: Fixed a small bug when calculating segmentHeight.

34

General / MS VS 2010 Problem ?

« on: September 11, 2010, 07:53:47 am »

Or you can select View->Property manager and select the property sheet named Microsoft.Cpp.Win32.user and make the changes there. That way you get them for all your projects.

35

Graphics / Optimizing tilerendering

« on: September 10, 2010, 07:35:13 am »

If you have it optimized to only draw what you see, I think that you don't need to do anything more.

Does SFML draw sprites that are completely off screen? Do I have to do my own frustum culling?

36

General / VS C++ Express : SFML Window tutorial

« on: September 05, 2010, 04:38:56 pm »

How do I link two?
sfml-system.lib sfml-window.lib ?
sfml-system.lib, sfml-window.lib ?
sfml-system.lib; sfml-window.lib ?

sfml-system.lib; sfml-window.lib

37

SFML projects / Excellence (previously Eve Shooter)

« on: September 03, 2010, 10:08:50 am »

I haven't played your game yet, but looking at the video it looks like the background is completely static. If you scroll it slowly down it'll look like the ships is actually moving forward.

38

General discussions / Help with VC++ Express 2010

« on: September 02, 2010, 07:57:43 am »

What libraries are you linking with? What lib path do you have on the properties page?

I'm using VS2010 Ultimate without any problems, so I guess it's nothing major.