Implement EnvironmentCamera

[wahn]

I asked on the PBRT mailing list (pbrt@googlegroups.com):

Are there any example .pbrt files for EnvironmentCamera and/or RealisticCamera? I couldn't find any example scenes using them ...

And Haarm-Pieter Duiker replied with:

https://github.com/hpd/PBRTForMaya/tree/master/maya/renderData

Finding the one example for the EnvironmentCamera:

> rg environment
pbrt_feature_demo_camera_environment.pbrt
27:Camera "environment"

And the resulting image (rendered with the C++ version of PBRT):

Now, lets add the Rust code to render the same image ...

[wahn]

Here an image rendered by the Rust version (after fixing some parser problems - see commit 3a3eefd):

The environment camera was replaced by a perspective camera:

> git diff
diff --git a/maya/renderData/pbrt_feature_demo_camera_environment.pbrt b/maya/renderData/pbrt_feature_demo_camera_environment.pbrt
index 7d4182f..7ec17de 100644
--- a/maya/renderData/pbrt_feature_demo_camera_environment.pbrt
+++ b/maya/renderData/pbrt_feature_demo_camera_environment.pbrt
@@ -24,7 +24,7 @@ Accelerator "bvh"
 # Camera begin
 Scale -1 1 1
 LookAt 0.000000 4.250000 -45.000000 -0.000000 -0.177129 -2.878684 -0.000000 0.994522 0.104528
-Camera "environment"
+Camera "perspective"
        "float screenwindow" [-1.0 1.0 -0.5 0.5]
 # Camera end

We had to use the Rust version with OpenEXR support, but everything is prepared now to work on the EnvironmentCamera ...

[wahn]

After commit 1ac0ef5 the Rust version (with OpenEXR support) renders fine: