不需要Ableton：将Ableton Push 2连接到VCV机架

struct AbletonPush2 : Module {
    midi::Output midiOutput;
    midi::InputQueue midiInput;

    bool inputConnected;
    bool outputConnected;
}

void connectPush() {
    auto in_devs = midiInput.getDeviceIds();
    for (int i = 0; i < in_devs.size(); i++){
        if (midiInput.getDeviceName(in_devs[i]).find("Ableton") != std::string::npos) {
            midiInput.setDeviceId(in_devs[i]);
            inputConnected = true;
            break;
        }
    }
		
    auto out_devs = midiOutput.getDeviceIds();
    for (int i = 0; i < out_devs.size(); i++){
        if (midiOutput.getDeviceName(out_devs[i]).find("Ableton") != std::string::npos) {
            midiOutput.setDeviceId(out_devs[i]);
            outputConnected = true;
            break;
        }
    }
}

void process(const ProcessArgs &args) override {
    if (sampleCounter > args.sampleRate / updateFrequency) {

        if ((!inputConnected) && (!outputConnected)) {
            connectPush();
        }

	midi::Message msg;
	while (midiInput.shift(&msg)) {
	    processMidi(msg);
	}
    }
}

void lightOn(int note, int color){
    midi::Message msg;
    msg.setNote(note);
    msg.setValue(color);
    msg.setChannel(1);
    msg.setStatus(0x9);
    midiOutput.sendMessage(msg);
}

void lightOff(int note){
    midi::Message msg;
    msg.setNote(note);
    msg.setValue(0);
    msg.setChannel(1);
    msg.setStatus(0x8);
    midiOutput.sendMessage(msg);
}

#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif

#include <stdio.h>

#ifdef _WIN32

// see following link for a discussion of the
// warning suppression:
// http://sourceforge.net/mailarchive/forum.php?
// thread_name=50F6011C.2020000%40akeo.ie&forum_name=libusbx-devel

// Disable: warning C4200: nonstandard extension used:
// zero-sized array in struct/union
#pragma warning(disable:4200)

#include <windows.h>
#endif

#ifdef __linux__
#include <libusb-1.0/libusb.h>
#else
#include "libusb.h"
#endif

#define ABLETON_VENDOR_ID 0x2982
#define PUSH2_PRODUCT_ID  0x1967

static libusb_device_handle* open_push2_device()
{
  int result;

  if ((result = libusb_init(NULL)) < 0)
  {
    printf("error: [%d] could not initilialize usblib\n", result);
    return NULL;
  }

  libusb_set_debug(NULL, LIBUSB_LOG_LEVEL_ERROR);

  libusb_device** devices;
  ssize_t count;
  count = libusb_get_device_list(NULL, &devices);
  if (count < 0)
  {
    printf("error: [%ld] could not get usb device list\n", count);
    return NULL;
  }

  libusb_device* device;
  libusb_device_handle* device_handle = NULL;

  char ErrorMsg[128];

  // set message in case we get to the end of the list w/o finding a device
  sprintf(ErrorMsg, "error: Ableton Push 2 device not found\n");

  for (int i = 0; (device = devices[i]) != NULL; i++)
  {
    struct libusb_device_descriptor descriptor;
    if ((result = libusb_get_device_descriptor(device, &descriptor)) < 0)
    {
      sprintf(ErrorMsg,
        "error: [%d] could not get usb device descriptor\n", result);
      continue;
    }

    if (descriptor.bDeviceClass == LIBUSB_CLASS_PER_INTERFACE
      && descriptor.idVendor == ABLETON_VENDOR_ID
      && descriptor.idProduct == PUSH2_PRODUCT_ID)
    {
      if ((result = libusb_open(device, &device_handle)) < 0)
      {
        sprintf(ErrorMsg,
          "error: [%d] could not open Ableton Push 2 device\n", result);
      }
      else if ((result = libusb_claim_interface(device_handle, 0)) < 0)
      {
        sprintf(ErrorMsg,
          "error: [%d] could not claim interface 0 of Push 2 device\n", result);
        libusb_close(device_handle);
        device_handle = NULL;
      }
      else
      {
        break; // successfully opened
      }
    }
  }

  if (device_handle == NULL)
  {
    printf(ErrorMsg);
  }

  libusb_free_device_list(devices, 1);
  return device_handle;
}

static void close_push2_device(libusb_device_handle* device_handle)
{
  libusb_release_interface(device_handle, 0);
  libusb_close(device_handle);
}

struct Push2Display : FramebufferWidget {

    unsigned char frame_header[16] = {
          0xFF, 0xCC, 0xAA, 0x88,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00,
          0x00, 0x00, 0x00, 0x00 
    };

    libusb_device_handle* device_handle;

    unsigned char* image;

    void sendDisplay(unsigned char * image) {
        int actual_length;
     
        libusb_bulk_transfer(device_handle, PUSH2_BULK_EP_OUT, frame_header, sizeof(frame_header), &actual_length, TRANSFER_TIMEOUT);
        for (int i = 0; i < 160; i++)
            libusb_bulk_transfer(device_handle, PUSH2_BULK_EP_OUT, &image[(159 - i)*1920], 2048, &actual_length, TRANSFER_TIMEOUT);
    }
}

void drawFramebuffer() override {

    NVGcontext* vg = APP->window->vg;

    if (display_connected) {
        nvgSave(vg);
	glViewport(0, 0, 960, 160);
        glClearColor(0, 0, 0, 0);
        glClear(GL_COLOR_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);

	nvgBeginFrame(vg, 960,  160, 1);
        draw(vg);
        nvgEndFrame(vg);

        glReadPixels(0, 0, 960, 160, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, image); 

        //  XOR   ,  
        for (int i = 0; i < 80*960; i ++){
            image[i * 4] ^= 0xE7;
	    image[i * 4 + 1] ^= 0xF3;
            image[i * 4 + 2] ^= 0xE7;
	    image[i * 4 + 3] ^= 0xFF;
        }
	    	
	sendDisplay(image);

	nvgRestore(vg);
    }

    dirty = true;
}