Don't alter the scene's active cameras in the middle of taking a scre…

[carolhmj]

…enshot with RenderTargetTexture, because we can just set the RTT active camera instead.

Related to: https://forum.babylonjs.com/t/how-to-freeze-the-camera/34284/10 so we don't need to manually set the scene's active camera after taking a screenshot.

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[RaananW]

Just need to clean up the file (unused imports)

[Popov72]

Unfortunately this change won't work because the list of meshes as seen by the screenshot camera is not refreshed correctly.

Try this PG: https://playground.babylonjs.com/#85EGZM#22

There is a sphere on the left but not visible by the main scene camera. When taking a screenshot (hit Spacebar and look at the browser console), you should see:

because the screenshot camera is put on the right of the box and is looking down the -x axis, so the sphere is visible.

With the PR, you won't see the sphere because the list of meshes that is used to render into the RTT is the list of active meshes of the main scene camera (so only the box in the PG). It is this line of code in RenderTargetTexture._renderToTarget which is doing that:

            const defaultRenderList = this.renderList ? this.renderList : scene.getActiveMeshes().data;

That's why the current screenshot code is replacing the scene camera by the screenshot camera and is doing scene.render() => this call is triggering a recomputation of the list of active meshes as seen by the current scene camera.

[sebavan]

flag as request changes to prevent merge following @Popov72 comments

[carolhmj]

Unfortunately this change won't work because the list of meshes as seen by the screenshot camera is not refreshed correctly.

Try this PG: https://playground.babylonjs.com/#85EGZM#22

There is a sphere on the left but not visible by the main scene camera. When taking a screenshot (hit Spacebar and look at the browser console), you should see:

because the screenshot camera is put on the right of the box and is looking down the -x axis, so the sphere is visible.

With the PR, you won't see the sphere because the list of meshes that is used to render into the RTT is the list of active meshes of the main scene camera (so only the box in the PG). It is this line of code in RenderTargetTexture._renderToTarget which is doing that:

            const defaultRenderList = this.renderList ? this.renderList : scene.getActiveMeshes().data;

That's why the current screenshot code is replacing the scene camera by the screenshot camera and is doing scene.render() => this call is triggering a recomputation of the list of active meshes as seen by the current scene camera.

In this case, could we add the scene's meshes explicitly to the RTT? Like this:

for (const node of scene.getNodes()) {
        if (node instanceof AbstractMesh) {
            texture.renderList?.push(node);
        }
    }

[Popov72]

Yes, I think that should do it.

However, you can do it in a simpler way:

texture.renderList = scene.meshes.slice();

The only thing is that frustum culling is not applied on those meshes, so they will be sent to the GPU even if they are not visible. I guess it's not really a problem for a screenshot. If it is, you will have to perform a loop instead and call mesh.isInFrustum(frustumPlanes) for each mesh before pushing it in the list (note: to get the planes to pass to isInFrustum(), you can do frustumPlanes = Frustum.GetPlanes(camera.getTransformationMatrix());).

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To prevent this PR from going to the changelog marked it with the "skip changelog" label.

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