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fdivitto / FabGL

ESP32 Display Controller (VGA, PAL/NTSC Color Composite, SSD1306, ST7789, ILI9341), PS/2 Mouse and Keyboard Controller, Graphics Library, Sound Engine, Game Engine and ANSI/VT Terminal
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Display not appearing after image is run #140

Closed i-am-shodan closed 3 years ago

i-am-shodan commented 3 years ago

Hi I'm trying to get the PCEmulator sketch to work. I have a TTGO VGA32 1.4 and crucially a HDMI monitor.

I have altered the sketch to use ibox.begin(VGA_640x480_60Hz, 400, 300);. I then get the set up menu on screen through my VGA converter. If I actually run an image then I lose VGA.

My guess was that the display mode is being set to CGA/EGA or something at a resolution beyond what my converter box can handle. I bought a HD Video Converter Board,CGA/EGA/YUV/RGB to VGA Converter Board in the hope that if I was running at low DOS resolution I would get something out of it.

I'm a bit stumped now so I have some questions:

i-am-shodan commented 3 years ago

OK I understand some of the problem now. The converter I have is a GBS 8200 and converts analog RGB to VGA. The TTGO VGA32 output digital RGB.

I think that when the emulator boots up it moves into a super low res CGA graphics mode that the HDMI adapter I have does not support.

i-am-shodan commented 3 years ago

Would it be possible to display a high res like VGA_640x480_60Hz but draw at a CGI resolution in the centre?

i-am-shodan commented 3 years ago

I've had a go at hacking graphicsadapter.cpp and have been able to force 640x480 with this:

      case Emulation::PC_Text_40x25_16Colors:
        //printf("Emulation::PC_Text_40x25_16Colors\n");
        setFont(&FONT_8x16);
        setCursorShape(13, 15);
        m_VGADCtrl.setDrawScanlineCallback(drawScanline_PC_Text_80x25_16Colors, this);
        m_VGADCtrl.setScanlinesPerCallBack(8);
        m_VGADCtrl.setResolution(VGA_640x480_60Hz); // VGA_320x200_70Hz
        m_VGADCtrl.convertModelineToTimings(VGA_320x200_70Hz, &timings); // todo ret check

        viewPortWidth  = ~3 & timings.HVisibleArea; // view port width must be 32 bit aligned
        viewPortHeight = timings.VVisibleArea;

        m_columns = viewPortWidth / m_font.width;
        m_rows    = viewPortHeight / m_font.height;
        break;

FreeDos seems to work with some garbage at the bottom of the screen which I'm assuming is uninitialized memory.

i-am-shodan commented 3 years ago

I've fixed text mode with this:

void IRAM_ATTR GraphicsAdapter::drawScanline_PC_Text_80x25_16Colors_Hack(void * arg, uint8_t * dest, int scanLine)
{
  constexpr int SCREENWIDTH      = 640;

  if (scanLine >= 400)
  {
    for (int x = 0; x < SCREENWIDTH * 8; ++x) {
        auto destptr = dest + x; 
        *destptr = 192; // black
    }
  }
  else
  {
    drawScanline_PC_Text_80x25_16Colors(arg, dest, scanLine);
  }
}

Can't get display mode to work with a similar hack. I'm guessing the colours or something need to be converted.

i-am-shodan commented 3 years ago

I've now fixes all modes apart from PC_Graphics_HGC_720x348 to work with a HDMI adapter. I will send a PR.

fdivitto commented 3 years ago

cutting a 480 resolution to 400 results in a ugly black band. Have you also tried to set "double scan"?

I can successfully use a VGA to HDMI converter using following changes: VGA_320x200_70Hz -> VGA_320x200_60HzD (used for 40x25 text mode) VGA_640x400_70Hz -> VGA_640x400_60Hz (used for 80x25 text mode) VGA_320x200_70Hz -> VGA_320x200_60HzD (used for CGA 320x200 mode) VGA_640x200_70Hz -> VGA_640x200_60HzD (used for CGA 640x200 mode) VGA_720x348_73Hz -> VGA_720x348_50HzD (used for Hercules high res mode)

Attached there is graphicsadapter.cpp with above changes.

graphicsadapter.cpp.zip

i-am-shodan commented 3 years ago

I couldn’t find a list of compatible HDMI adapters anywhere so I bought two different ones on Amazon. Neither of the HDMI adapters I used supported VGA_640x400_60Hz. But I suppose it could also be the monitor I used.

Are any of these other modes documented anywhere? Is there a list of HDMI adapters?

fdivitto commented 3 years ago

I use the cheapest VGA2HDMI converter there is around (this one )...

i-am-shodan commented 3 years ago

Mine looks very similar but in black. Must be the monitor not liking the res.

fdivitto commented 3 years ago

link just updated

fdivitto commented 3 years ago

my converter supports 640x400 at 60Hz. However this night I will try to find a double scan resolution which is actually a 640x480 (but you will be 640x240, so we will try to remove the ugly black band)...

i-am-shodan commented 3 years ago

I wouldn’t rush, I’ve literally spent 3 days authoring a PR to fix this.

fdivitto commented 3 years ago

not the best solution, but all resolutions have been now adjusted to be usable on most monitors and adapters