Suggestion: add API to check if a texture is equal using the internal id

[dgcor]

Some SFML classes use the m_cacheId to optimize the code. Because this is private, it can't be used from the outside.

One trick is to use the same name for a class (sf::Text) so you can friend sf::Texture and use this member internally. The downside is you get problems if someone or some dependency includes the original sf::Text (class redefinition).

My suggestion is to add some way to verify if a texture changed since its last use.

void Text::ensureGeometryUpdate() const
{
	if (!m_font)
	{
		return;
	}

	// Do nothing, if geometry has not changed and the font texture has not changed
	if (!m_geometryNeedUpdate && m_font->getTexture(m_characterSize).m_cacheId == m_fontTextureId)
	{
		return;
	}

related forum posts:
https://en.sfml-dev.org/forums/index.php?topic=14560.0

[eXpl0it3r]

Can you provide some concrete use cases for exposing Cache ID?

[dgcor]

I have a custom Text2 class which is a copy/paste of sf::text but with 2 extra styles for left and right text alignment:

https://github.com/dgcor/DGEngine.core/blob/master/src/SFML/Text2.cpp
https://github.com/dgcor/DGEngine.core/blob/master/src/SFML/Text2.h

enum Style
{
	Regular = 0,
	Bold = 1 << 0,
	Italic = 1 << 1,
	Underlined = 1 << 2,
	StrikeThrough = 1 << 3,
	HorizontalAlignCenter = 1 << 4,
	HorizontalAlignRight = 1 << 5
};

I can't compile it with Clang because of the existing sf::text conflict. msvc and gcc compile ok. I can remove the cache check and rename it to sf::Text2 and then it works on all compilers, but it will always be slower than the original implementation.

I only use it to draw this wall of text:

Another reason is that I'm migrating to C++20 modules and I can't have this trick of using the existing name to get the friend access to m_cacheId as easily.