Controlling Camera Entity in Scene

How-to Discussions
1

Am I missing something or maybe it’s just my long summer vacation, but I’m not able to control the camera entity in Scene.

<Scene Camera="Camera1" ux:ClassName="MyScene" ClearColor="0, 0, 0, 1">

    <Entity ux:Name="Camera1">
        <Frustum FovDegrees="120" ZNear="10" ZFar="4500" ux:Name="Camera1Frustum" />
        <Transform3D Position="0, 0, 0" RotationDegrees="0, 0, 0" Scaling="1, 1, 1" ux:Name="Camera1Transform" />
    </Entity>

</Scene>

And in Scene class I do :

protected override void OnDraw(Fuse.DrawContext dc)
{
    var time = (float)Uno.Application.Current.FrameTime;

    Camera.Transform.Position = float3(200 * Math.Sin(time),0,-500);

    Camera.Transform.LookAt(float3(0,0,0), float3(0,1,0));


    dc.Clear(float4(0,0,0,0), 1);

    draw dc, DefaultShading, Fuse.Drawing.Primitives.Cube;

}

This doesn’t seems to have any effect on what happens on the screen. All I see is a little grey rectangle at the left up corner of the screen.

Help, please.

2

Hey,

Is this <Scene> inside an <App> ? How does your complete UX look?

3

Yep, Scene is just inside App

<App Theme="Basic" ux:ClassName="MainView" ClearColor="#000000FF">
    <MyScene />
</App>
4

Are you sure it is actually redrawing each frame?

5

Yes. Added debug_log "time "+time;

inside OnDraw() at Scene and it prints out the time every frame.

6

Hm, you are doing some manual draw here. Probably applying dc doesn’t do what it once did. You might have to set up your draw statement a bit more elaborately.

7

OH wait,

You are overriding Scene.OnDraw() ? Then the camera is never pushed. You need to let the Scene do it’s thing, and implement your drawing in a RenderNode or Component, inside the scene.

8

yep

9

Oh yes that’s it.

So here’s how you can render 3D stuff with Fuse/Uno and control the camera:

<App ClearColor="#000000FF">

  <Scene Camera="CameraEntity" ClearColor="0,0,0,1">

      <Entity ux:Name="CameraEntity">
          <Frustum FovDegrees="120" ZNear="10" ZFar="4500" />
          <Transform3D Position="0, 0, 0" RotationDegrees="0, 0, 0" Scaling="1, 1, 1" />
      </Entity>

      <MyRenderNode Camera="CameraEntity" />

  </Scene>

  </App>

And you have a MyRenderNode.ux:

<RenderNode ux:Class="MyRenderNode" />

And it’s class:

using Uno;
using Fuse;
using Fuse.Entities;

public partial class MyRenderNode
{
    public Entity Camera {get;set;}

    protected override void OnDraw(Fuse.DrawContext dc)
    {
        var time = (float)Uno.Application.Current.FrameTime;

        Camera.Transform.Position = float3(200 * Math.Sin(time),0,-500);

        Camera.Transform.LookAt(float3(0,0,0), float3(0,1,0));

        Camera.Frustum.FovRadians = Math.PIf/3.0f;

        dc.Clear(float4(0,0,0,0), 1);
        draw dc, DefaultShading, Fuse.Drawing.Primitives.Cube
        {
            Scaling:float3(100);
        };

    }

}
10

Great :slight_smile:

Some simplifications you can do:

  • The RenderNode doesn’t have to be in it’s own UX file, it is perfectly fine to have nested classes.

  • The Camera is pushed on the DrawContext when you use it on the scene, so you can get that from there instead of setting it explicitly on the RenderNode

  • You don’t need to repeat the ClearColor on both the app and the scene

The code can then look like this:

<App ClearColor="#000">

    <Scene Camera="CameraEntity">

        <Entity ux:Name="CameraEntity">
            <Frustum FovDegrees="120" ZNear="10" ZFar="4500" />
            <Transform3D Position="0, 0, 0" RotationDegrees="0, 0, 0" Scaling="1, 1, 1" />
        </Entity>

        <RenderNode ux:Class="MyRenderNode" />

    </Scene>

</App>

And to get the camera in Uno:

var camera = (Entity)dc.Camera;
11

Cool.

How should the MyRenderNode class look like in that case?

I now only have a MyRenderNode.uno class and it looks like:

using Uno;
using Fuse;
using Fuse.Entities;

public partial class MyRenderNode : RenderNode
{
    protected override void OnDraw(Fuse.DrawContext dc)
    {
        debug_log "foo";

        var _camera = (Entity)dc.Camera;

        var time = (float)Uno.Application.Current.FrameTime;

        _camera.Transform.Position = float3(200 * Math.Sin(time),0,-500);

        _camera.Transform.LookAt(float3(0,0,0), float3(0,1,0));

        _camera.Frustum.FovRadians = Math.PIf/3.0f;

        dc.Clear(float4(0,0,0,0), 1);
        draw dc, DefaultShading, Fuse.Drawing.Primitives.Cube
        {
            Scaling:float3(100);
        };

    }

}

But that draw is not called. Compiler doesn’t whine about anything.

12

If it’s the same as before:

    using Uno;
    using Fuse;
    using Fuse.Entities;

    public partial class MyRenderNode
    {
        protected override void OnDraw(Fuse.DrawContext dc)
        {
            debug_log "foo";

            var _camera = (Entity)dc.Camera;

            var time = (float)Uno.Application.Current.FrameTime;

            _camera.Transform.Position = float3(200 * Math.Sin(time),0,-500);

            _camera.Transform.LookAt(float3(0,0,0), float3(0,1,0));

            _camera.Frustum.FovRadians = Math.PIf/3.0f;

            dc.Clear(float4(0,0,0,0), 1);
            draw dc, DefaultShading, Fuse.Drawing.Primitives.Cube
            {
                Scaling:float3(100);
            };

        }

    }

I get .cache\GeneratedCode\MainView.g.uno(3,12): E3002: ‘MyRenderNode’ already has a static constructor

13

Looks like you now have both a stand alone MyRenderNode and the inline one, resulting in double code generation for that class.

Not sure why it doesn’t render, need more info to debug.