This function is useful for accumulating relative mouse motion if you want to only handle whole pixel movement.
e.g.
static float dx_frac, dy_frac;
float dx, dy;
/* Accumulate new motion with previous sub-pixel motion */
dx = event.motion.xrel + dx_frac;
dy = event.motion.yrel + dy_frac;
/* Split the integral and fractional motion, dx and dy will contain whole pixel deltas */
dx_frac = SDL_modff(dx, &dx);
dy_frac = SDL_modff(dy, &dy);
if (dx != 0.0f || dy != 0.0f) {
...
}
In SDL3 we plan to make more use of shaders in the 2D render API, and this minimizes the number of platforms we have to consider for new features. OpenGL ES 2.0 or newer is supported on all modern iOS and Android devices.
I ran this script in the include directory:
```sh
sed -i '' -e 's,#include "\(SDL.*\)",#include <SDL3/\1>,' *.h
```
I ran this script in the src directory:
```sh
for i in ../include/SDL3/SDL*.h
do hdr=$(basename $i)
if [ x"$(echo $hdr | egrep 'SDL_main|SDL_name|SDL_test|SDL_syswm|SDL_opengl|SDL_egl|SDL_vulkan')" != x ]; then
find . -type f -exec sed -i '' -e 's,#include "\('$hdr'\)",#include <SDL3/\1>,' {} \;
else
find . -type f -exec sed -i '' -e '/#include "'$hdr'"/d' {} \;
fi
done
```
Fixes https://github.com/libsdl-org/SDL/issues/6575
