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Help => Graphics => Topic started by: Calmatory on October 18, 2009, 03:15:16 am

Title: Small problem with Sprites
Post by: Calmatory on October 18, 2009, 03:15:16 am

Consider the following two chunks of code:
sprite.hpp:

Code: [Select]


/* sprite.h */
#ifndef SPRITE_H_
#define SPRITE_H_
#include <string>
#include <SFML/Graphics.hpp>
class CSprite {
    friend class CEngine;
private:
    sf::Image m_TempImage;
    sf::Sprite s_Hero[4];
    sf::Sprite s_Grass;
    sf::Sprite s_Gravel;
    sf::Sprite s_Sky;
public:
    CSprite();
    ~CSprite();
    bool LoadSprite(std::string filename, sf::Sprite &sprite);

};
#endif

and sprite.cpp:

Code: [Select]


/* sprite.cpp */
#include "include/sprite.hpp"

CSprite::CSprite() {
/* Constructor */
}

CSprite::~CSprite() {
/* Destructor */
}

    bool CSprite::LoadSprite(std::string filename, sf::Sprite &sprite) {
if(!m_TempImage.LoadFromFile(filename)) {
   return true;
} else {
sprite.SetImage(m_TempImage);
return false;
}
}


The files obviously try to handle sprite loading. The problem however is that when I call LoadSprite for example like this:

Code: [Select]


    Sprites.LoadSprite("gravel.png", Sprites.s_Gravel);
    Sprites.LoadSprite("grass.png", Sprites.s_Grass);
    Sprites.LoadSprite("sky.png", Sprites.s_Sky);


ONLY the last sprite seems to have the correct binded to it. All the previous sprites will have the LAST sprites image in them. Consider the following example:

Code: [Select]


    Sprites.s_Grass.SetPosition(0,0);
    m_App.Draw(Sprites.s_Grass);

    Sprites.s_Gravel.SetPosition(8,8);
    m_App.Draw(Sprites.s_Gravel);

    Sprites.s_Sky.SetPosition(16,16);
    m_App.Draw(Sprites.s_Sky);


Yields 3 Sprites.s_Sky sprites, instead of 3 different sprites.

If I change the order of LoadSprite functions, to load say s_Gravel as the last sprite, then ALL the loaded sprites will have the image of s_Gravel.

I suspect that I am doing something wrong with the m_TempImage in the LoadSprite function declaration. Though, I am not sure.

Any thoughts?

Title: Small problem with Sprites
Post by: Hiura on October 18, 2009, 04:04:16 am

'cause all sprite have the same sorite as reference so the laser load is "used" for all sprite. You need to use something else to store your sf::image, for example an image manager (see my wiki).

Title: Small problem with Sprites
Post by: Calmatory on October 18, 2009, 04:19:30 am

So every sf::Sprite object needs it's own sf::Image object?

That makes sense though, and the symptoms indicate to it.

Thank you. :)

Title: Small problem with Sprites
Post by: Hiura on October 18, 2009, 12:48:39 pm

Quote from: "Calmatory"

So every sf::Sprite object needs it's own sf::Image object?

That's it.

Title: Small problem with Sprites
Post by: Nexus on October 18, 2009, 05:11:17 pm

Quote from: "Calmatory"

So every sf::Sprite object needs it's own sf::Image object?

To be more precise, every sf::Sprite object needs its own reference/pointer to an sf::Image object. The image itsself is stored independently from the sprite.

The separation of those two concepts allows more flexibility and is far more efficient than having a huge pixel-array for each sprite.