MSFS I stumble in nvgMoveTo and nvgLineTo in Nanovg

[mariomotta]

Have mercy on me, explain to me why in this code:

void Gunsight::OuterCircle(void) {
    nvgBeginPath(ctx);
    nvgEllipse(ctx, 0, 0, size.w, size.h);
    nvgStrokeColor(ctx, nvgRGBAf(255, 255, 255, alpha));
    nvgStrokeWidth(ctx, thickness);
    nvgStroke(ctx);
    nvgClosePath(ctx);
   
}
//////////////////////////////
void Gunsight::Pipper(void) {
    // pipper
    nvgBeginPath(ctx);
    nvgEllipse(ctx, -10, -10, 10, 10);
    nvgStrokeColor(ctx, nvgRGBAf(255, 255, 255, alpha));
    nvgStrokeWidth(ctx, thickness);
    nvgStroke(ctx);
    nvgClosePath(ctx);
}
///////////////////////////////
void Gunsight::Crosses(void) {
    nvgBeginPath(ctx);
    nvgMoveTo(ctx, center.x, center.y - size.h/2.0);
    nvgLineTo(ctx, center.x, center.y - size.h/4.0);
    nvgMoveTo(ctx, center.x - size.w/2.0, center.y);
    nvgLineTo(ctx, center.x - size.w/4.0, center.y);
    nvgStrokeColor(ctx, nvgRGBAf(255, 255, 255, alpha));
    nvgStrokeWidth(ctx, thickness);
    nvgStroke(ctx);
    nvgClosePath(ctx);
}

both OuterCircle() and Pipper() work nicely instead Crosses() refuses to draw 2 simple lines even if called in sequence:

nvgBeginFrame(myGunsight->ctx, p_draw_data->winWidth, p_draw_data->winHeight, pxRatio);
{
// go to center 
nvgTranslate(myGunsight->ctx, myGunsight->center.x, myGunsight->center.y);
// Outer circle   
myGunsight->OuterCircle();   
// pipper
myGunsight->Pipper();
// fails
myGunsight->Crosses();
}
nvgEndFrame(myGunsight->ctx);

 

[Prepar3DGuy]

In your Crosses method you use center.x and center.y like you working in absolute coordinates, but after calling nvgTranslate in first time yours zeros are already in the center of canvas.
Try this.

void Gunsight::Crosses(void) {
    nvgBeginPath(ctx);
    nvgMoveTo(ctx, 0, -size.h/4.0);
    nvgLineTo(ctx, 0, size.h/4.0);
    nvgMoveTo(ctx, -size.w/4.0, 0);
    nvgLineTo(ctx, size.w/4.0, 0);
    nvgStrokeColor(ctx, nvgRGBAf(255, 255, 255, alpha));
    nvgStrokeWidth(ctx, thickness);
    nvgStroke(ctx);
    nvgClosePath(ctx);
}

 

[mariomotta]

Thanks a lot, really appreciated.
btw: shame on me, i would realize it before watching how circle coordinates are set :-(
Yet another issue, look at the attached picture, how to make gunsight glass transparent ?
I'm not a modeller, could not make it transparent, any clues ?
tia
/Mario

 

[Prepar3DGuy]

I think it is possible to draw WASM gauge output on to glass surface texture. I'm less than beginner in 3D design and blender user. Just quick try with glass material settings inside Blender (Huge thanks to Blender2MSFS team) and that is my ugly results.

Unfortunately this is only flat texture, not HUD as it must behavior when you move point of view. Maybe MSFS Porthole or Parallax materials are more suitable. Oh, there are so much settings for all this materials.

 

[mariomotta]

Thanks, will give a try using parallx materials
/Mario