Use this function to set the global gain of the specified haptic device.
int SDL_HapticSetGain(SDL_Haptic* haptic, int gain)
the SDL_Haptic device to set the gain on
value to set the gain to, should be between 0 and 100 (0 - 100)
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
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Device must support the SDL_HAPTIC_GAIN feature.
The user may specify the maximum gain by setting the environment variable SDL_HAPTIC_GAIN_MAX which should be between 0 and 100. All calls to SDL_HapticSetGain() will scale linearly using SDL_HAPTIC_GAIN_MAX as the maximum.
This function is available since SDL 2.0.0.