SFML 2.5.0 Update (Or how I learned to hate RenderTextures)

 

 

On May 6th, the C++ Simple and Fast Media Library (or SFML for short) was updated to stable version 2.5.0, adding various updates including more optimial iOS support, bug fixes, added functionality for Text and Audio and various optimizations. For such a big release, it made sense to upgrade and get my Vigilante Game Framework updated, and why not update Gemstone Keeper while I’m at it?

Well it took nearly a month, but I did manage it in the end. Gemstone Keeper 1.0.5 has been uploaded to Steam, both for Windows and Linux!

As the title suggest, a lot of the work had to do with the updates to the sf::RenderTexture object. However, I don’t absolutely hate them, they are extremely useful for rendering a scene to an area of the screen, or to apply post-processing effects to. However the problem lied in how I was using them, and how the fixes done in the latest update effectively broke my engine’s rendering system.

The initial update showed promise, as my most recent game worked fine, but moving onto the framework’s examples and Gemstone Keeper showed that a lot of things weren’t rendering at all.

Vigilante Framework currently renders 3D models using Modern OpenGL, and while it was working fine with SFML 2.4.2, it rendered nothing with SFML 2.5.0. The solution was embarrassingly simple despite the amount of effort put into fixing it, including implementing my own version of SFML’s glCheck function and re-writing SFML’s own OpenGL example to run with modern OpenGL. When rendering the 3D scene, I modified some of the OpenGL states, which wouldn’t be an issue before but now those OpenGL states carry over into other contexts. The solution was to simply make sure that the GL states were reset BEFORE rendering the scene using a sprite object.

 ///Render 3D scene and apply to a sprite.
 RenderTarget.resetGLStates(); //Reset the GL states to the default for SFML
 Sprite->Draw(RenderTarget); //Render the sprite.

Gemstone Keeper however uses legacy OpenGL, and while I could have updated the VFrame source code but that could take more time to fix. Regardless, I was able to get it working by rearranging other objects that define sf::RenderTexture, including the bloom post processing effect and the help popup terminal.

Gemstone Keeper’s other graphics were another story. The approached I had been using up to this point was to render text objects onto a single rendertexture, and then store the generated texture to be used as a sprite, particle or tilemap. While this was okay for the time, but it is rather inefficient and bad for graphical memory.

I wanted to do a single-texture approach, where all the graphics are rendered onto a single texture, and a rectangle area is specified when creating renderable objects, for a while but I kept putting it off. SFML’s update, causing any newly created render textures to dereference generated textures, it was time to take this approach on. The best part is that most of the work was already done by myself with the additional code of Jukka Jylänki’s MaxRectBinPacker algorithm, all that needed doing was to change how I defined renderables from setting the texture to whatever the name of the genrated texture is to the name of one texture sheet, and to get the correct rectangle from a map/dictionary, searching by string ID.

CaptureCaptureCapture

Now this doesn’t mean the entire game’s visuals are rendered from one texture. Including the 3D gemstones, any assets that use a repeated texture grabs a subsection of the main texture as a copy, same applies to the VBackdrop as well. Getting the icon was a more painful looking process of converting the entire texture sheet to an sf::Image, so I can load in a subsection to a new sf::Texture object, and then convert the new texture object to an sf::Image in order to set it to be the application icon.

sf::IntRect iconArea = TextureData::p()->GetTextureRect(TextureData::p()->GetPortalTextureName(true));
 sf::Image image = VGlobal::p()->Content->LoadTexture("TextureSheet").copyToImage();
 sf::Texture tex;
 tex.loadFromImage(image, iconArea);
 VGlobal::p()->App->setIcon(iconArea.width, iconArea.height, tex.copyToImage().getPixelsPtr());

Like I said, not pretty.

So enjoy Gemstone Keeper, the number of you who own it. Now back to doing more stuff in C++…

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s