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    Would you like to play Nokia (J2ME) games on Retropie?

    Scheduled Pinned Locked Moved Ideas and Development
    sdlemulatorawesome
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    • recompileR
      recompile @Hex
      last edited by

      @hex Out of curiosity, what is the game you want rotated?

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      • HexH
        Hex
        last edited by Hex

        @recompile Asphalt6 (480x800)

        Rotation is proving to be much difficult that anticipated. Working on this till I get controller back

        Also I lost the Xbox controller. Cant have it back till the little bro finishes playing Minecraft :|

        Sent from 20,000 leagues under the sea.

        Powersaver Emulation station : https://github.com/hex007/EmulationStation
        ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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        • recompileR
          recompile @Hex
          last edited by

          @hex I see what you mean now. Rotation makes sense for those cases.

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          • HexH
            Hex
            last edited by

            @recompile Can we change the parameter to not need the file:// part ?

            So you could have -f ./Asphalt6.jar
            else -u http://.....

            Sent from 20,000 leagues under the sea.

            Powersaver Emulation station : https://github.com/hex007/EmulationStation
            ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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            • recompileR
              recompile @Hex
              last edited by

              @hex Probably, but the only people who will see it are you and I. Everyone else will launch games from ES. Are you just looking to use relative paths, or are you just sick of typing the whole path every time?

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              • HexH
                Hex
                last edited by

                @recompile Sick of typing. File:// does not auto complete so while trying different games for testing i have to copy paste or type very carefully. defeats the purpose of running it from terminal.

                suggested changes would be much better. Very few will leverage "-u" option anyways so it will make testing easier.

                Sent from 20,000 leagues under the sea.

                Powersaver Emulation station : https://github.com/hex007/EmulationStation
                ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                • recompileR
                  recompile @Hex
                  last edited by

                  @hex I just use a shell script:

                  #!/bin/sh
                  java -jar freej2me-rpi.jar file:/home/pi/RetroPie/roms/j2me/ShadoWalker.jar 240 320
                  

                  I have nine or so named like test.sh, test2.sh, nokia.sh, etc. for whatever I'm looking to check at the moment. It saves a lot of time and typing.

                  Also, pressing up on the command line will scroll through previous commands. Very handy.

                  I like simple.

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                  • HexH
                    Hex
                    last edited by

                    Can it be please modified to take shell paths like /home/hex/a.jar or ./a.jar or a.jar

                    Syntax wise I am thinking this

                    java -jar freej2me.jar file/url W H [-r 90] [-i interpolation]

                    Sent from 20,000 leagues under the sea.

                    Powersaver Emulation station : https://github.com/hex007/EmulationStation
                    ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                    • recompileR
                      recompile @Hex
                      last edited by

                      @hex Yes, but it adds a lot of unnecessary complexity, can be very fragile, and still ambiguous. Is the path intended to be relative to the current working directory or the location of the jar file?

                      I like simple. I see this as adding complexity without adding any value.

                      Simplicity is actually the reason why it takes a url instead of a 'normal' path. It was simpler to implement and required less code.

                      To your specific problem: It looks like you just want to reference a file in the current directory. Here's how you do that:

                      java -jar freej2me.jar file:./a.jar
                      

                      @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                      Syntax wise I am thinking this

                      That's fine. How do you want to receive it on the C side? Just W H R I?

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                      • HexH
                        Hex
                        last edited by Hex

                        @recompile Got xbox controller back. Updated C sources. Check it out and let me know if it works as expected or creates any unexpected errors.

                        Sent from 20,000 leagues under the sea.

                        Powersaver Emulation station : https://github.com/hex007/EmulationStation
                        ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                        • HexH
                          Hex
                          last edited by Hex

                          @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                          That's fine. How do you want to receive it on the C side? Just W H R I?

                          W H I [R]

                          R is optional

                          @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                          Is the path intended to be relative to the current working directory or the location of the jar file?

                          Always relative to working directory

                          ~/ > ls
                          --> jsdl/    games/    music/    videos/     roms/
                          
                          ~/ > java -jar jsdl/freej2me.jar games/Asphalt.jar W H 
                          

                          Sent from 20,000 leagues under the sea.

                          Powersaver Emulation station : https://github.com/hex007/EmulationStation
                          ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                          • recompileR
                            recompile
                            last edited by recompile

                            @Hex A couple things:

                            Most importantly, it doesn't compile on my pi3.

                            sdl_interface.cpp: In function ‘void removeJoystick(SDL_JoystickID)’:
                            sdl_interface.cpp:60:10: error: ‘axisIt’ does not name a type
                                auto axisIt = mPrevAxisValues.find(joyId);
                                     ^
                            sdl_interface.cpp:61:14: error: ‘axisIt’ was not declared in this scope
                                delete[] axisIt->second;
                                         ^
                            sdl_interface.cpp:65:10: error: ‘joyIt’ does not name a type
                                auto joyIt = mJoysticks.find(joyId);
                                     ^
                            sdl_interface.cpp:66:8: error: ‘joyIt’ was not declared in this scope
                                if(joyIt != mJoysticks.end())
                                   ^
                            

                            Still important, it's over-complicated. You've made things more difficult for yourself.

                            Why are you storing the previous axis value and not the previous normalized value? It makes things much more complicated than they need to be. By storing the normalized value, you won't need 'deadzone' at all. Try something like this:

                            // Normalize
                            normValue = 0; 
                            if(event.jaxis.value > 0)
                            {
                               normValue = 1;
                            }
                            else if (event.jaxis.value < 0)
                            {
                                 normValue = -1;
                            }
                            

                            Next, you can compare your normalized values to the ones previously stored. How you store them is up to you, but it will affect how you compare them later.

                            Keeping things similar to how you're doing things already, let's assume you'll store them like this after the compare:

                            mPrevAxisValues[event.jaxis.which][event.jaxis.axis] = normValue; 
                            

                            Comparing the old value to the new value to send pressed and released events:

                            // Remember that the UD axis is 0, LR is 1 
                            // axisShift will let us pack UDLR neatly in to the event key value
                            // resulting i: UP - 8, Down - 4, Left - 2, Right - 1
                            axisShift = event.jaxis.axis * 2;
                            
                            oldValue = mPrevAxisValues[event.jaxis.which][event.jaxis.axis];
                            if(oldValue != normValue)
                            {
                                // DPad Button Released
                                if(oldValue ==   1) { sendKey(4, 2<<axisShift); } // Up, Left
                                if(oldValue ==  -1) { sendKey(4, 1<<axisShift); } // Down, Right
                                // DPad Button Pressed
                                if(normValue ==  1) { sendKey(5, 2<<axisShift); } // Up, Left
                                if(normValue == -1) { sendKey(5, 1<<axisShift); } // Down, Right
                            }
                            

                            My example uses a simplified Send Key:

                            void sendKey(int eventType, int key)
                            {
                             unsigned char bytes [5];
                             bytes[0] = (char) eventType;
                             bytes[1] = (char) (key >> 24);
                             bytes[2] = (char) (key >> 16);
                             bytes[3] = (char) (key >> 8);
                             bytes[4] = (char) (key);
                             fwrite(&bytes, sizeof(char), 5, stdout);
                            }
                            

                            Smaller is not always better. I tend to put readability over compactness. I've never regretted those decisions, but I have lots of regrets related to those times when I put compactness over readability.

                            HexH 1 Reply Last reply Reply Quote 0
                            • HexH
                              Hex
                              last edited by Hex

                              @recompile You can use this flag while compiling -std=c++11. My gcc supports is automatically. On pi you might need to add that flag.

                              I copied code from ES. Even if i changed it later the output would remain same hence i did not optimize then (2am)

                              void sendKey(int key, bool pressed, bool joystick)
                              {
                              	unsigned char bytes [5];
                              	bytes[0] = (char) 2 * joystick + pressed;
                              

                              Is quite self explanatory

                              Byte shifting is not easily visualisable for me.

                              I shall make the changes but I will keep the send key. I am thinking of changing the following line

                              bytes[0] = (char) 2 * joystick + pressed;
                              to
                              bytes[0] = (char) (joystick << 16) + pressed;

                              so we have
                              00,01,10,11

                              Should that be ok?

                              Sent from 20,000 leagues under the sea.

                              Powersaver Emulation station : https://github.com/hex007/EmulationStation
                              ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                              • HexH
                                Hex
                                last edited by

                                @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                                Why are you storing the previous axis value and not the previous normalized value? It makes things much more complicated than they need to be. By storing the normalized value, you won't need 'deadzone' at all. Try something like this:

                                deadzone will always be needed as it is a cutoff threshold. If we dont have a cutoff even slight movement of analog stick will spew unnecessary events.

                                Sent from 20,000 leagues under the sea.

                                Powersaver Emulation station : https://github.com/hex007/EmulationStation
                                ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                                • HexH
                                  Hex @recompile
                                  last edited by

                                  @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                                  // DPad Button Released
                                  if(oldValue ==   1) { sendKey(4, 2<<axisShift); } // Up, Left
                                  if(oldValue ==  -1) { sendKey(4, 1<<axisShift); } // Down, Right
                                  // DPad Button Pressed
                                  if(normValue ==  1) { sendKey(5, 2<<axisShift); } // Up, Left
                                  if(normValue == -1) { sendKey(5, 1<<axisShift); } // Down, Right
                                  

                                  I dont understand why you are ending 4 and 5

                                  Sent from 20,000 leagues under the sea.

                                  Powersaver Emulation station : https://github.com/hex007/EmulationStation
                                  ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                                  • HexH
                                    Hex
                                    last edited by

                                    @recompile I have updated the source. Can you update it.

                                    To compile :
                                    g++ -std=c++11 -lSDL2 -lpthread -o sdl_interface sdl_interface.cpp

                                    Sent from 20,000 leagues under the sea.

                                    Powersaver Emulation station : https://github.com/hex007/EmulationStation
                                    ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                                    • recompileR
                                      recompile @Hex
                                      last edited by

                                      @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                      deadzone will always be needed as it is a cutoff threshold. If we dont have a cutoff even slight movement of analog stick will spew unnecessary events.

                                      Take a second look at what I've sent. By comparing the normalized values, and sending events only on change, we won't send needless events on, for example, a change of -29087 to -18542 (which is what you're deadzone is trying to avoid) as we'll instead be comparing -1 to -1 and seeing no change.

                                      @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                      I dont understand why you are ending 4 and 5

                                      We had used 1 and 0 as the event type for key pressed/released, 3 and 2 for gamepad button pressed/released. 5 and 4 for dpad pressed/released seemed to follow.

                                      @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                      I shall make the changes but I will keep the send key. I am thinking of changing the following line
                                      bytes[0] = (char) 2 * joystick + pressed;
                                      to
                                      bytes[0] = (char) (joystick << 16) + pressed;
                                      so we have
                                      00,01,10,11

                                      That doesn't make any sense to me as (char) (joystick << 16) + pressed is identical to (char) pressed . It also won't result in the values you suggest. you'll get on 0 or 1.

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                                      • HexH
                                        Hex
                                        last edited by Hex

                                        @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                                        // Normalize
                                        normValue = 0;
                                        if(event.jaxis.value > 0)
                                        {
                                        normValue = 1;
                                        }
                                        else if (event.jaxis.value < 0)
                                        {
                                        normValue = -1;
                                        }

                                        This is flawed. At rest my event.jaxis.value is 0. Which is okay. When analog stick is moved slightly event.jaxis.value will not be 0 and trigger an event as it transitions from 0 to 1 or -1 (normalized). We dont want that. It should be a lot of movement before event gets registered. else you will end up with over sensitive response. Get it?


                                        @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                                        We had used 1 and 0 as the event type for key pressed/released, 3 and 2 for gamepad button pressed/released. 5 and 4 for dpad pressed/released seemed to follow.

                                        What i wanted here was to have a separate joystick(gamepad) or keyboard and pressed or released. Dpad is a pard of game controller. So in byte form we can either have
                                        00, 01, 02, 03 for combination of 2 bools or
                                        00, 01, 10, 11 either of them is fine.


                                        @recompile said in Would you like to play Nokia (J2ME) games on Retropie?:

                                        That doesn't make any sense to me as (char) (joystick << 16) + pressed is identical to (char) pressed

                                        From above if I have two{a,b} bools {0,1} and I want to get {00, 01, 02, 03} I am doing
                                        2 * a + b

                                        What should i do with bit shifting if I want {00,01,10,11} ? probably 4 rather than 16 :|
                                        (a << 4) + b

                                        Edit : Here is the hexadecimal o/p

                                        00000000: 0140 0000 4f  .@..O   // keyboard Press
                                        00000005: 0040 0000 4f  .@..O   // Kb release
                                        0000000a: 1100 0000 c7  .....   // Joystick press
                                        0000000f: 1000 0000 c8  .....   // Js release
                                        

                                        Sent from 20,000 leagues under the sea.

                                        Powersaver Emulation station : https://github.com/hex007/EmulationStation
                                        ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                                        • HexH
                                          Hex
                                          last edited by Hex

                                          @recompile I tried your code without deadzone. Xbox controller Dpad works as expected. Analog sticks dont work at all. Is this what you were after?

                                          SNES Dpad doesnt work with your code. as there is no reset event sent it always remains triggered after first press

                                          I was trying to get the analog sticks to work too like buttons hence the confusion.

                                          Sent from 20,000 leagues under the sea.

                                          Powersaver Emulation station : https://github.com/hex007/EmulationStation
                                          ES dev script : https://github.com/hex007/es-dev/blob/master/es-tests.sh

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                                          • recompileR
                                            recompile @Hex
                                            last edited by

                                            @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                            This is flawed. At rest my event.jaxis.value is 0. Which is okay. When analog stick is moved very little event.jaxis.value will not be 0 and trigger an event. We dont want that. It should be a lot of movement before event gets registered. else you will end up with over sensitive response. Get it?

                                            I do, but that's not what your 'deadzone' code does. I followed your lead there, as that was what you seemed to want. As you're worried about values close to 0, I explained how to deal with that earlier. That explanation is adapted here:

                                            // Normalize
                                            normValue = 0;
                                            if(event.jaxis.value > 500)
                                            {
                                            normValue = 1;
                                            }
                                            else if (event.jaxis.value < -500)
                                            {
                                            normValue = -1;
                                            }

                                            @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                            What should i do with bit shifting if I want {00,01,10,11} ? probably 8 rather than 16 :|
                                            (a << 8) + b

                                            Bit shifting is just bit shifting. Say I have the number 8:

                                               8 = [0000 1000] = 8
                                            8<<1 = [0001 0000] = 16
                                            8<<2 = [0010 0000] = 32
                                            8>>1 = [0000 0100] = 4
                                            8>>2 = [0000 0010] = 2
                                            

                                            1 byte is 8 bits, So if you have a 1 and shift left by 16, you'll end up with 0, as the one bit that makes up your 1 gets dropped off the end. The same is true if you try to shift left by 8, you'll drop that 1 right off the end.

                                            If you want to pack bools together in to a byte, you just need to shift them left to the position you want. let's pack bools a,b,c, and d in to a byte in that order.

                                            mybyte = (a<<3) | (b<<2) | (c<<1) | d;
                                            

                                            (The | operator is bitwise-or Let me know if you don't understand why I've used it.)

                                            To answer your question What should i do with bit shifting if I want {00,01,10,11} ? :

                                            bytes[0] = (char) ((joystick << 1) | pressed);
                                            

                                            A left-shift is just like multiplying by two (see the earlier example). So that is actually equivalent to your old code (from memory, but I think this is what you had):

                                            bytes[0] = (char) (joystick * 2 + pressed);
                                            

                                            The only reason I can see to change that would have been to clarify your intent, but a comment would have done that just as well.

                                            @hex said in Would you like to play Nokia (J2ME) games on Retropie?:

                                            What i wanted here was to have a separate joystick(gamepad) or keyboard and pressed or released.

                                            If you want to use event types 2 and 3 for buttons as well as dpad, I guess that's fine, you just have to make sure you're using unique values. We've got 32 bits to work with, so you could just shift all the dpad values in to the next byte, leaving the lower 8-bits for buttons. You really only need two bits, my example used four for clarity. We've got bits to spare, so it doesn't cost anything to add a bit of readability.

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