Fisheye Camera for Cycles

For sample images see:
http://www.dalaifelinto.com/?p=399 (equisolid)
http://www.dalaifelinto.com/?p=389 (equidistant)

The 'use_panorama' option is now part of a new Camera type: 'Panorama'.
Created two other panorama cameras:

- Equisolid: most of lens in the market simulate this lens - e.g. Nikon, Canon, ...)
             this works as a real lens up to an extent. The final result takes the
             sensor dimensions into account also.
             .:. to simulate a Nikon DX2S with a 10.5mm lens do:
                 sensor: 23.7 x 15.7
                 fisheye lens: 10.5
                 fisheye fov: 180
                 render dimensions: 4288 x 2848

- Equidistant: this is not a real lens model. Although the old equidistant lens simulate
               this lens. The result is always as a circular fisheye that takes the whole sensor
               (in other words, it doesn't take the sensor into consideration).
               This is perfect for fulldomes ;)

               For the UI we have 10 to 360 as soft values and 10 to 3600 as hard values (because we can).


Reference material:
http://www.hdrlabs.com/tutorials/downloads_files/HDRI%20for%20CGI.pdf
http://www.bobatkins.com/photography/technical/field_of_view.html

Note, this is not a real simulation of the light path through the lens.
The ideal solution would be this:
https://graphics.stanford.edu/wikis/cs348b-11/Assignment3
http://www.graphics.stanford.edu/papers/camera/


Thanks Brecht for the fix, suggestions and code review.
Kudos for the dome community for keeping me stimulated on the topic since 2009 ;)

Patch partly implemented during lab time at VisGraf, IMPA - Rio de Janeiro.

intern/cycles/render/camera.cpp

@@ -39,8 +39,14 @@ Camera::Camera()
 	use_motion = false;
 
 	type = CAMERA_PERSPECTIVE;
+	panorama_type = PANORAMA_EQUIRECTANGULAR;
+	fisheye_fov = M_PI_F;
+	fisheye_lens = 10.5f;
 	fov = M_PI_F/4.0f;
 
+	sensorwidth = 0.036;
+	sensorheight = 0.024;
+
 	nearclip = 1e-5f;
 	farclip = 1e5f;
 
@@ -181,6 +187,15 @@ void Camera::device_update(Device *device, DeviceScene *dscene, Scene *scene)
 	/* type */
 	kcam->type = type;
 
+	/* panorama */
+	kcam->panorama_type = panorama_type;
+	kcam->fisheye_fov = fisheye_fov;
+	kcam->fisheye_lens = fisheye_lens;
+
+	/* sensor size */
+	kcam->sensorwidth = sensorwidth;
+	kcam->sensorheight = sensorheight;
+
 	/* store differentials */
 	kcam->dx = float3_to_float4(dx);
 	kcam->dy = float3_to_float4(dy);
@@ -208,6 +223,8 @@ bool Camera::modified(const Camera& cam)
 		(fov == cam.fov) &&
 		(nearclip == cam.nearclip) &&
 		(farclip == cam.farclip) &&
+		(sensorwidth == cam.sensorwidth) &&
+		(sensorheight == cam.sensorheight) &&
 		// modified for progressive render
 		// (width == cam.width) &&
 		// (height == cam.height) &&
@@ -217,7 +234,10 @@ bool Camera::modified(const Camera& cam)
 		(top == cam.top) &&
 		(matrix == cam.matrix) &&
 		(motion == cam.motion) &&
-		(use_motion == cam.use_motion));
+		(use_motion == cam.use_motion) &&
+		(panorama_type == cam.panorama_type) &&
+		(fisheye_fov == cam.fisheye_fov) &&
+		(fisheye_lens == cam.fisheye_lens));
 }
 
 void Camera::tag_update()