Cameras, draw calls, and SFML View
In all our previous projects, all the entities in our games (with one exception) were graphically represented with a sprite. This is fine when there are only a few, a few dozen, or even a few hundred entities being drawn. It is important because the speed that SFML can draw each frame of our game has a direct relationship to the number of times we call window.draw. This is not an SFML flaw but is directly connected to how OpenGL uses the graphics card.
The reason is that each time we call draw, quite a lot happens behind the scenes to set up OpenGL so that it is ready to draw. To quote the SFML website,
“…each call [to draw] involves setting a set of OpenGL states, resetting matrices, changing textures, etc. All of this is required even when simply drawing two triangles (a sprite).”
So, using a vertex array and rendering multiple images with one draw call to do our drawing, whenever possible, is a very...
