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MSFS20 C++ gauges nightmare

M

mariomotta

Messages
162
Country
italy
Someone like me is fighting pointlessly to try to run gauges in C++ ?
it’s a nightmare.
For instance:
Code: 
PCSTRINGZ custom_event_id_name = "custom_event_id"; 
struct CustomEvent {    ID id;    ENUM value; }; 
CustomEvent custom_event_id = { 0,0 }; 
// Callbacks 
extern "C" { 
   MSFS_CALLBACK bool custom_event_gauge_callback(FsContext ctx, int service_id, void* pData)    { 
       ID id = 0;
        ID check_id = 0;
        switch (service_id)        { 
       case PANEL_SERVICE_PRE_INSTALL:        {
            ID check_id = check_named_variable(custom_event_id_name);
            if (check_id < 0) {
                id = register_named_variable(custom_event_id_name);
                custom_event_id.id = id; 
           }  
          return true; 
       }
none of above works.
register_named_variable(custom_event_id_name) does not register anything and return always 0
consequently check_named_variable(custom_event_id_name); fails always.
any clues ?
tia
Mario
 
mariomotta said:
Someone like me is fighting pointlessly to try to run gauges in C++ ?
it’s a nightmare.
For instance:
Code: 
PCSTRINGZ custom_event_id_name = "custom_event_id";
struct CustomEvent {    ID id;    ENUM value; };
CustomEvent custom_event_id = { 0,0 };
// Callbacks
extern "C" {
   MSFS_CALLBACK bool custom_event_gauge_callback(FsContext ctx, int service_id, void* pData)    {
       ID id = 0;
        ID check_id = 0;
        switch (service_id)        {
       case PANEL_SERVICE_PRE_INSTALL:        {
            ID check_id = check_named_variable(custom_event_id_name);
            if (check_id < 0) {
                id = register_named_variable(custom_event_id_name);
                custom_event_id.id = id;
           } 
          return true;
       }
none of above works.
register_named_variable(custom_event_id_name) does not register anything and return always 0
consequently check_named_variable(custom_event_id_name); fails always.
any clues ?
tia
Mario
Click to expand...
Maybe it's a double declaration of check_id?
 
That definately won't help. Also, I'd put the code in PRE_UPDATE because you can't guarantee that PRE_INSTALL will update when you want it too.
 
DragonflightDesign said:
That definately won't help. Also, I'd put the code in PRE_UPDATE because you can't guarantee that PRE_INSTALL will update when you want it too.
Click to expand...
I can debug the code, PRE_INSTALL is called several times, not a big issue, however
Code: 
register_named_variable(custom_event_id_name);
i'm stuck here.
Someone has tried to make a working C++ gauge ? (hope yes) :-(
 
Hi,

You should try:

Code: 
       case PANEL_SERVICE_CONNECT_TO_WINDOW:        {
            ID check_id = register_named_variable(custom_event_id_name);
             custom_event_id.id = id; 
           }  
          return true;

With that snippet you are registering an LVAR only once. No need to check whether or not it is already registered.

Tomas
 
In Tomas' response, the return is assigned to check_id... and the value of id (which is assigned to custom_event_id.id is undefined. So... I'd change = id to = check_id. I would also avoid declaring variables in the middle of code. I can't count the number of times I've found bugs in people's code because of that one.
 
I'm with Ed on variable declarations. I truly dislike Microsoft for promoting the use of variable declaration anywhere in dotNet. Declare everything at the top of the code and assign it an initial variable. Failure to assign an initial value will lead to what is euphemistically refered to as 'undefined behaviour' because you will have no idea what crap the operating system has dumped in the variable when you come to use it.
 
If it's a local stack variable (one only used in a function), declare it at the beginning of the function.
 
taguilo said:
You should try:

Code: 
       case PANEL_SERVICE_CONNECT_TO_WINDOW:        {
            ID check_id = register_named_variable(custom_event_id_name);
             custom_event_id.id = id;
           } 
          return true;
Click to expand...
How and when you got PANEL_SERVICE_CONNECT_TO_WINDOW for WASM gauge callback function in MSFS?
In SDK 0.6.0 (C Gauges -> Events received by the gauge callback) [Why the hell they doesn't publish SDK on web for hyperlinks? or I have missed something]
there is no mention about it in service_id. By the way in gauges.h there are more PANEL_SERVICE_xxx, but in my test gauge I have only received and logged service_id = 2, 3, 4, 5, [6, 7, 10, 11], 12, 13.
 
mariomotta said:
Someone has tried to make a working C++ gauge ? (hope yes) :-(
Click to expand...
Yes. This quick example works fine.
C++: 
// My demo of wasm gauge

#include <MSFS/MSFS.h>
#include <MSFS/MSFS_Render.h>
#include <MSFS/Render/nanovg.h>
#include <MSFS/Legacy/gauges.h>

#include <map>
#include <cstring>
#include <string>
#include <sstream>
#include <fstream>

// Names for my variables
PCSTRINGZ custom_var_name = "var1";
PCSTRINGZ custom_var_name2 = "var2";

struct sGaugeVars
{
    int iFont;
    ID id_var_1;
    ID id_var_2;
};

std::stringstream g_Log;

std::map<FsContext, sGaugeVars> g_GaugeVars;
std::map<FsContext, NVGcontext*> g_GaugeNVGcontext;

extern "C" MSFS_CALLBACK bool DemoGauge1_gauge_callback(FsContext ctx, int service_id, void* pData)
{
    // local variables for debug view
    ID a = 0, b = 0;

    switch (service_id)
    {
    case PANEL_SERVICE_PRE_INSTALL:
    {
        sGaugeInstallData* p_install_data = (sGaugeInstallData*)pData;
        g_GaugeVars[ctx].iFont = -1;
        // Register variables names
        g_GaugeVars[ctx].id_var_1 = register_named_variable(custom_var_name);
        g_GaugeVars[ctx].id_var_2 = register_named_variable(custom_var_name2);
        
        // Check received IDs in debugger's Local window
        a = g_GaugeVars[ctx].id_var_1;
        b = g_GaugeVars[ctx].id_var_2;

        g_Log << "Registered variables: "
            << custom_var_name << " with ID: " << a << " "
            << custom_var_name2 << " with ID: " << b << std::endl;

        return true;
    }
    break;
    case PANEL_SERVICE_POST_INSTALL:
    {
        NVGparams params;
        params.edgeAntiAlias = true;
        params.userPtr = ctx;
        g_GaugeNVGcontext[ctx] = nvgCreateInternal(&params);
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        g_GaugeVars[ctx].iFont = nvgCreateFont(nvgctx, "serif", "./data/Roboto-Regular.ttf");
        return true;
    }
    break;
    case PANEL_SERVICE_PRE_INITIALIZE: break;
    case PANEL_SERVICE_POST_INITIALIZE:
    {
        // set default values for variables
        if (check_named_variable(custom_var_name) != -1 )
            set_named_variable_value(g_GaugeVars[ctx].id_var_1, 0.);
        if (check_named_variable(custom_var_name2) != -1)
            set_named_variable_value(g_GaugeVars[ctx].id_var_2, 9999.);
    }
    break;
    case PANEL_SERVICE_PRE_UPDATE:
    {
        // change variables values
        set_named_variable_value(g_GaugeVars[ctx].id_var_1, get_named_variable_value(g_GaugeVars[ctx].id_var_1) + 0.1);
        set_named_variable_value(g_GaugeVars[ctx].id_var_2, get_named_variable_value(g_GaugeVars[ctx].id_var_2) - 0.1);
    }
    break;
    case PANEL_SERVICE_POST_UPDATE: break;
    case PANEL_SERVICE_PRE_DRAW:
    {
        sGaugeDrawData* p_draw_data = (sGaugeDrawData*)pData;
        float pxRatio = (float)p_draw_data->fbWidth / (float)p_draw_data->winWidth;
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        nvgBeginFrame(nvgctx, p_draw_data->winWidth, p_draw_data->winHeight, pxRatio);
        {
            // Black background
            nvgFillColor(nvgctx, nvgRGB(0, 0, 0));
            nvgBeginPath(nvgctx);
            nvgRect(nvgctx, 0, 0, p_draw_data->winWidth, p_draw_data->winHeight);
            nvgFill(nvgctx);

            /// Output variables values
            if (g_GaugeVars[ctx].iFont != -1)
            {
                char str[50] = "";

                nvgFontFaceId(nvgctx, g_GaugeVars[ctx].iFont);
                nvgFontSize(nvgctx, 0.1f * p_draw_data->winHeight);
                nvgTextAlign(nvgctx, NVG_ALIGN_LEFT | NVG_ALIGN_TOP);
                nvgFillColor(nvgctx, nvgRGB(250, 250, 250));

                sprintf(str, "var1 ID: %d Value: %5.1f", g_GaugeVars[ctx].id_var_1, get_named_variable_value(g_GaugeVars[ctx].id_var_1));
                nvgText(nvgctx, 0, 0.2f * p_draw_data->winHeight, str, (const char*)NULL);
                g_Log << str << " ";

                sprintf(str, "var2 ID: %d Value: %5.1f", g_GaugeVars[ctx].id_var_2, get_named_variable_value(g_GaugeVars[ctx].id_var_2));
                nvgText(nvgctx, 0, 0.4f * p_draw_data->winHeight, str, (const char*)NULL);
                g_Log << str << std::endl;
            }
        }
        nvgEndFrame(nvgctx);
        return true;
    }
    break;
    case PANEL_SERVICE_POST_DRAW: break;
    case PANEL_SERVICE_PRE_KILL:
    {
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        nvgDeleteInternal(nvgctx);
        g_GaugeNVGcontext.erase(ctx);

        return true;
    }
    break;
    case PANEL_SERVICE_POST_KILL:
    {
        // Save log to text file
        // %LOCALAPPDATA%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages\mycompany-aircraft-wasm-gauge\work\gauge_log.txt
        std::ofstream out("\\work\\gauge_log.txt", std::ios::app);
        if (out.is_open())
        {
            out << g_Log.rdbuf();
            out.close();
        }
        g_GaugeVars.erase(ctx);
        g_Log.clear();
        return true;
    }
    break;
    }
    return false;
}

Screenshot 2020-10-06 012014.png
Screenshot 2020-10-06 012322.png
 
  • Like
Reactions: tml
Prepar3DGuy said:
Yes. This quick example works fine.
C++: 
// My demo of wasm gauge

#include <MSFS/MSFS.h>
#include <MSFS/MSFS_Render.h>
#include <MSFS/Render/nanovg.h>
#include <MSFS/Legacy/gauges.h>

#include <map>
#include <cstring>
#include <string>
#include <sstream>
#include <fstream>

// Names for my variables
PCSTRINGZ custom_var_name = "var1";
PCSTRINGZ custom_var_name2 = "var2";

struct sGaugeVars
{
    int iFont;
    ID id_var_1;
    ID id_var_2;
};

std::stringstream g_Log;

std::map<FsContext, sGaugeVars> g_GaugeVars;
std::map<FsContext, NVGcontext*> g_GaugeNVGcontext;

extern "C" MSFS_CALLBACK bool DemoGauge1_gauge_callback(FsContext ctx, int service_id, void* pData)
{
    // local variables for debug view
    ID a = 0, b = 0;

    switch (service_id)
    {
    case PANEL_SERVICE_PRE_INSTALL:
    {
        sGaugeInstallData* p_install_data = (sGaugeInstallData*)pData;
        g_GaugeVars[ctx].iFont = -1;
        // Register variables names
        g_GaugeVars[ctx].id_var_1 = register_named_variable(custom_var_name);
        g_GaugeVars[ctx].id_var_2 = register_named_variable(custom_var_name2);
    
        // Check received IDs in debugger's Local window
        a = g_GaugeVars[ctx].id_var_1;
        b = g_GaugeVars[ctx].id_var_2;

        g_Log << "Registered variables: "
            << custom_var_name << " with ID: " << a << " "
            << custom_var_name2 << " with ID: " << b << std::endl;

        return true;
    }
    break;
    case PANEL_SERVICE_POST_INSTALL:
    {
        NVGparams params;
        params.edgeAntiAlias = true;
        params.userPtr = ctx;
        g_GaugeNVGcontext[ctx] = nvgCreateInternal(&params);
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        g_GaugeVars[ctx].iFont = nvgCreateFont(nvgctx, "serif", "./data/Roboto-Regular.ttf");
        return true;
    }
    break;
    case PANEL_SERVICE_PRE_INITIALIZE: break;
    case PANEL_SERVICE_POST_INITIALIZE:
    {
        // set default values for variables
        if (check_named_variable(custom_var_name) != -1 )
            set_named_variable_value(g_GaugeVars[ctx].id_var_1, 0.);
        if (check_named_variable(custom_var_name2) != -1)
            set_named_variable_value(g_GaugeVars[ctx].id_var_2, 9999.);
    }
    break;
    case PANEL_SERVICE_PRE_UPDATE:
    {
        // change variables values
        set_named_variable_value(g_GaugeVars[ctx].id_var_1, get_named_variable_value(g_GaugeVars[ctx].id_var_1) + 0.1);
        set_named_variable_value(g_GaugeVars[ctx].id_var_2, get_named_variable_value(g_GaugeVars[ctx].id_var_2) - 0.1);
    }
    break;
    case PANEL_SERVICE_POST_UPDATE: break;
    case PANEL_SERVICE_PRE_DRAW:
    {
        sGaugeDrawData* p_draw_data = (sGaugeDrawData*)pData;
        float pxRatio = (float)p_draw_data->fbWidth / (float)p_draw_data->winWidth;
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        nvgBeginFrame(nvgctx, p_draw_data->winWidth, p_draw_data->winHeight, pxRatio);
        {
            // Black background
            nvgFillColor(nvgctx, nvgRGB(0, 0, 0));
            nvgBeginPath(nvgctx);
            nvgRect(nvgctx, 0, 0, p_draw_data->winWidth, p_draw_data->winHeight);
            nvgFill(nvgctx);

            /// Output variables values
            if (g_GaugeVars[ctx].iFont != -1)
            {
                char str[50] = "";

                nvgFontFaceId(nvgctx, g_GaugeVars[ctx].iFont);
                nvgFontSize(nvgctx, 0.1f * p_draw_data->winHeight);
                nvgTextAlign(nvgctx, NVG_ALIGN_LEFT | NVG_ALIGN_TOP);
                nvgFillColor(nvgctx, nvgRGB(250, 250, 250));

                sprintf(str, "var1 ID: %d Value: %5.1f", g_GaugeVars[ctx].id_var_1, get_named_variable_value(g_GaugeVars[ctx].id_var_1));
                nvgText(nvgctx, 0, 0.2f * p_draw_data->winHeight, str, (const char*)NULL);
                g_Log << str << " ";

                sprintf(str, "var2 ID: %d Value: %5.1f", g_GaugeVars[ctx].id_var_2, get_named_variable_value(g_GaugeVars[ctx].id_var_2));
                nvgText(nvgctx, 0, 0.4f * p_draw_data->winHeight, str, (const char*)NULL);
                g_Log << str << std::endl;
            }
        }
        nvgEndFrame(nvgctx);
        return true;
    }
    break;
    case PANEL_SERVICE_POST_DRAW: break;
    case PANEL_SERVICE_PRE_KILL:
    {
        NVGcontext* nvgctx = g_GaugeNVGcontext[ctx];
        nvgDeleteInternal(nvgctx);
        g_GaugeNVGcontext.erase(ctx);

        return true;
    }
    break;
    case PANEL_SERVICE_POST_KILL:
    {
        // Save log to text file
        // %LOCALAPPDATA%\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages\mycompany-aircraft-wasm-gauge\work\gauge_log.txt
        std::ofstream out("\\work\\gauge_log.txt", std::ios::app);
        if (out.is_open())
        {
            out << g_Log.rdbuf();
            out.close();
        }
        g_GaugeVars.erase(ctx);
        g_Log.clear();
        return true;
    }
    break;
    }
    return false;
}

View attachment 63214View attachment 63215
Click to expand...
Thanks a lot, will give a try.
/Mario
just checked, it compiles nicely however watching in the MSFS console window i see it's not initialized nor loaded for some reason, so won't work on my side, sorry.
my call in panel.cfg
Code: 
htmlgauge00=WasmInstrument/WasmInstrument.html?wasm_module=demo.wasm&wasm_gauge=DemoGauge1, 0,0,1024,76
and console window says:
WASM: Failed to load module (not found in the VFS)
thanks for help.
/Mario
 
Last edited:
WarpD said:
In Tomas' response, the return is assigned to check_id... and the value of id (which is assigned to custom_event_id.id is undefined. So... I'd change = id to = check_id. I would also avoid declaring variables in the middle of code. I can't count the number of times I've found bugs in people's code because of that one.
Click to expand...
thanks.
no conflict because the 2 check_id are not declared "in the middle of code" but in different scopes, compiler won't be confused, simply the outer check_id is initialzed at 0 and remains unused, while the inner check_id should have the right id returned from register function, which is not, and will disappear out of his scope..
simply
 
I said nothing about the compiler being confused. I am stating that it is bad practice because declaring a variable on the fly like that can lead to serious issues. I have seen this many, many times in people's code. I simply can not stress strongly enough that this is a practice that should be shunned. It's bad, bad... really bad. Over 40 years here in writing software... and I'll say it again... just because you can, doesn't mean you should. It's a bad coding method. There is quite literally no valid reason to declare a variable on the fly like that.
 
mariomotta said:
thanks.
no conflict because the 2 check_id are not declared "in the middle of code" but in different scopes, compiler won't be confused, simply the outer check_id is initialzed at 0 and remains unused, while the inner check_id should have the right id returned from register function, which is not, and will disappear out of his scope..
simply
Click to expand...
Im a bit late, but im getting the same "WASM: Failed to load module (not found in the VFS)". Have you found any fixes for this?
 
Hello,
yes, was my fault, most of time it means that C++ -> WASM compiler found erros on your code, opening console on the game and looking at the errors should reveal what the problem is.
/Mario
 
with SDK 0.9 it not quite hard to do WASM using C++.
I feel, it more simple than FSX C++ GDI+. I just spend 10 days just porting over P3D aircraft code to native fs2020.
 
It's not really clear in what circumstances C++ gauge development makes sense over javascript.

I don't think there's a practical speed difference within the sim given the coding practices common in gauges (I have a PhD in computer science so I understand the diffference in execution model and that trivial instruction sequences execute quicker in WASM than JS) . My guess is C++ -> WASM gauge code will be deprecated in due course (shock, horror). Of course those with 'legacy' C++ gauge code will want to migrate rather then re-write but I don't think I would use C++ otherwise.

While I'm on a rant, the naming of the most basic calls used in gauge code in C++ and JS make me smile, i.e "get_named_variable_value()" and "SimVars.GetSimVarValue()". No-one thought just "SimVars.get()" ?
 
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