Getting DosBox In Full Screen With Scanlines

There is really something special about being able to play classic Dos games in RetroPie. The only issue is that by default the settings are the most optimal. DosBox produces a blurry image.

It is not fullscreen, and scanlines are not present. You can also check out our Retro Gaming USB Controller List.

RetroPie Parts List

Raspberry PI 3 Model BAvailable Here(The Main Computer)
Custom Cooling CaseAvailable Here(Fanless Cooling Case)
Micro SD CardAvailable Here(Minimum of 8GB)
Power SupplyAvailable Here(Minimum 5V 2.5A)
Game ControllerAvailable Here(Awesome Controller)

DosBox RetroPie Video Settings

In this quick guide we will show you how to get DosBox in fullscreen with the optimal settings in RetroPie.

DosBox Full Screen

The first thing we are going to want to change is the driver DosBox is using in RetroPie. We are going to change this driver to dispmanx SDL. To do this we need to enter the Retropie-Setup and enter the “Configuration/Tools” menu.


Now we are going to select the dispmanx configuration option from the menu selection screen.

Dispmanx Selection

Next we need to enable dispmanx support for the DosBox emulator in the options menu.

Dispmanx DosBox Enable

Lastly we need to update the dosbox-SVN.conf file in RetroPie with our modified file. This will enable fullscreen and scanlines into the image.

Simply copy the provided code below into your existing dosbox-SVN.conf completely replacing the files content at/opt/retropie/configs/pc/dosbox-SVN.conf with the one below.

# This is the configuration file for DOSBox SVN. (Please use the latest version of DOSBox)
# Lines starting with a # are comment lines and are ignored by DOSBox.
# They are used to (briefly) document the effect of each option.

#       fullscreen: Start dosbox directly in fullscreen. (Press ALT-Enter to go back)
#       fulldouble: Use double buffering in fullscreen. It can reduce screen flickering, but it can also result in a slow DOSBox.
#   fullresolution: What resolution to use for fullscreen: original, desktop or a fixed size (e.g. 1024x768).
#                     Using your monitor's native resolution with aspect=true might give the best results.
#                     If you end up with small window on a large screen, try an output different from surface.
# windowresolution: Scale the window to this size IF the output device supports hardware scaling.
#                     (output=surface does not!)
#           output: What video system to use for output.
#                   Possible values: surface, overlay.
#         autolock: Mouse will automatically lock, if you click on the screen. (Press CTRL-F10 to unlock)
#      sensitivity: Mouse sensitivity.
#      waitonerror: Wait before closing the console if dosbox has an error.
#         priority: Priority levels for dosbox. Second entry behind the comma is for when dosbox is not focused/minimized.
#                     pause is only valid for the second entry.
#                   Possible values: lowest, lower, normal, higher, highest, pause.
#       mapperfile: File used to load/save the key/event mappings from. Resetmapper only works with the default value.
#     usescancodes: Avoid usage of symkeys, might not work on all operating systems.


# language: Select another language file.
#  machine: The type of machine DOSBox tries to emulate.
#           Possible values: hercules, cga, tandy, pcjr, ega, vgaonly, svga_s3, svga_et3000, svga_et4000, svga_paradise, vesa_nolfb, vesa_oldvbe.
# captures: Directory where things like wave, midi, screenshot get captured.
#  memsize: Amount of memory DOSBox has in megabytes.
#             This value is best left at its default to avoid problems with some games,
#             though few games might require a higher value.
#             There is generally no speed advantage when raising this value.


# frameskip: How many frames DOSBox skips before drawing one.
#    aspect: Do aspect correction, if your output method doesn't support scaling this can slow things down!.
#    scaler: Scaler used to enlarge/enhance low resolution modes. If 'forced' is appended,
#            then the scaler will be used even if the result might not be desired.
#            Possible values: none, normal2x, normal3x, advmame2x, advmame3x, advinterp2x, advinterp3x, hq2x, hq3x, 2xsai, super2xsai, supereagle, tv2x, tv3x, rgb2x, rgb3x, scan2x, scan3x.


#      core: CPU Core used in emulation. auto will switch to dynamic if available and
#            appropriate.
#            Possible values: auto, dynamic, normal, simple.
#   cputype: CPU Type used in emulation. auto is the fastest choice.
#            Possible values: auto, 386, 386_slow, 486_slow, pentium_slow, 386_prefetch.
#    cycles: Amount of instructions DOSBox tries to emulate each millisecond.
#            Setting this value too high results in sound dropouts and lags.
#            Cycles can be set in 3 ways:
#              'auto'          tries to guess what a game needs.
#                              It usually works, but can fail for certain games.
#              'fixed #number' will set a fixed amount of cycles. This is what you usually
#                              need if 'auto' fails (Example: fixed 4000).
#              'max'           will allocate as much cycles as your computer is able to
#                              handle.
#            Possible values: auto, fixed, max.
#   cycleup: Amount of cycles to decrease/increase with keycombos.(CTRL-F11/CTRL-F12)
# cycledown: Setting it lower than 100 will be a percentage.


#   nosound: Enable silent mode, sound is still emulated though.
#      rate: Mixer sample rate, setting any device's rate higher than this will probably lower their sound quality.
#            Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
# blocksize: Mixer block size, larger blocks might help sound stuttering but sound will also be more lagged.
#            Possible values: 1024, 2048, 4096, 8192, 512, 256.
# prebuffer: How many milliseconds of data to keep on top of the blocksize.


#     mpu401: Type of MPU-401 to emulate.
#             Possible values: intelligent, uart, none.
# mididevice: Device that will receive the MIDI data from MPU-401.
#             Possible values: default, win32, alsa, oss, coreaudio, coremidi, none.
# midiconfig: Special configuration options for the device driver. This is usually the id of the device you want to use.
#               or in the case of coreaudio, you can specify a soundfont here.
#               When using a Roland MT-32 rev. 0 as midi output device, some games may require a delay in order to prevent 'buffer overflow' issues.
#               In that case, add 'delaysysex', for example: midiconfig=2 delaysysex
#               See the README/Manual for more details.


#  sbtype: Type of Soundblaster to emulate. gb is Gameblaster.
#          Possible values: sb1, sb2, sbpro1, sbpro2, sb16, gb, none.
#  sbbase: The IO address of the soundblaster.
#          Possible values: 220, 240, 260, 280, 2a0, 2c0, 2e0, 300.
#     irq: The IRQ number of the soundblaster.
#          Possible values: 7, 5, 3, 9, 10, 11, 12.
#     dma: The DMA number of the soundblaster.
#          Possible values: 1, 5, 0, 3, 6, 7.
#    hdma: The High DMA number of the soundblaster.
#          Possible values: 1, 5, 0, 3, 6, 7.
# sbmixer: Allow the soundblaster mixer to modify the DOSBox mixer.
# oplmode: Type of OPL emulation. On 'auto' the mode is determined by sblaster type. All OPL modes are Adlib-compatible, except for 'cms'.
#          Possible values: auto, cms, opl2, dualopl2, opl3, none.
#  oplemu: Provider for the OPL emulation. compat might provide better quality (see oplrate as well).
#          Possible values: default, compat, fast.
# oplrate: Sample rate of OPL music emulation. Use 49716 for highest quality (set the mixer rate accordingly).
#          Possible values: 44100, 49716, 48000, 32000, 22050, 16000, 11025, 8000.


#      gus: Enable the Gravis Ultrasound emulation.
#  gusrate: Sample rate of Ultrasound emulation.
#           Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
#  gusbase: The IO base address of the Gravis Ultrasound.
#           Possible values: 240, 220, 260, 280, 2a0, 2c0, 2e0, 300.
#   gusirq: The IRQ number of the Gravis Ultrasound.
#           Possible values: 5, 3, 7, 9, 10, 11, 12.
#   gusdma: The DMA channel of the Gravis Ultrasound.
#           Possible values: 3, 0, 1, 5, 6, 7.
# ultradir: Path to Ultrasound directory. In this directory
#           there should be a MIDI directory that contains
#           the patch files for GUS playback. Patch sets used
#           with Timidity should work fine.


# pcspeaker: Enable PC-Speaker emulation.
#    pcrate: Sample rate of the PC-Speaker sound generation.
#            Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
#     tandy: Enable Tandy Sound System emulation. For 'auto', emulation is present only if machine is set to 'tandy'.
#            Possible values: auto, on, off.
# tandyrate: Sample rate of the Tandy 3-Voice generation.
#            Possible values: 44100, 48000, 32000, 22050, 16000, 11025, 8000, 49716.
#    disney: Enable Disney Sound Source emulation. (Covox Voice Master and Speech Thing compatible).


# joysticktype: Type of joystick to emulate: auto (default), none,
#               2axis (supports two joysticks),
#               4axis (supports one joystick, first joystick used),
#               4axis_2 (supports one joystick, second joystick used),
#               fcs (Thrustmaster), ch (CH Flightstick).
#               none disables joystick emulation.
#               auto chooses emulation depending on real joystick(s).
#               (Remember to reset dosbox's mapperfile if you saved it earlier)
#               Possible values: auto, 2axis, 4axis, 4axis_2, fcs, ch, none.
#        timed: enable timed intervals for axis. Experiment with this option, if your joystick drifts (away).
#     autofire: continuously fires as long as you keep the button pressed.
#       swap34: swap the 3rd and the 4th axis. can be useful for certain joysticks.
#   buttonwrap: enable button wrapping at the number of emulated buttons.


# serial1: set type of device connected to com port.
#          Can be disabled, dummy, modem, nullmodem, directserial.
#          Additional parameters must be in the same line in the form of
#          parameter:value. Parameter for all types is irq (optional).
#          for directserial: realport (required), rxdelay (optional).
#                           (realport:COM1 realport:ttyS0).
#          for modem: listenport (optional).
#          for nullmodem: server, rxdelay, txdelay, telnet, usedtr,
#                         transparent, port, inhsocket (all optional).
#          Example: serial1=modem listenport:5000
#          Possible values: dummy, disabled, modem, nullmodem, directserial.
# serial2: see serial1
#          Possible values: dummy, disabled, modem, nullmodem, directserial.
# serial3: see serial1
#          Possible values: dummy, disabled, modem, nullmodem, directserial.
# serial4: see serial1
#          Possible values: dummy, disabled, modem, nullmodem, directserial.


#            xms: Enable XMS support.
#            ems: Enable EMS support. The default (=true) provides the best
#                 compatibility but certain applications may run better with
#                 other choices, or require EMS support to be disabled (=false)
#                 to work at all.
#                 Possible values: true, emsboard, emm386, false.
#            umb: Enable UMB support.
# keyboardlayout: Language code of the keyboard layout (or none).


# ipx: Enable ipx over UDP/IP emulation.


# Lines in this section will be run at startup.
# You can put your MOUNT lines here.

Then run DosBox in RetroPie as normal and enjoy the wonderful image. Also some users have reported changing the “aspect” to “true” as shown below to work better for their resolutions and television setups. So if you are having any issues try using the code below.


We hope this was helpful. You can also check out our Retro Gaming USB Controllers post.