/*
 * Copyright 2011, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "camera.h"
#include "scene.h"

#include "blender_sync.h"
#include "blender_util.h"

CCL_NAMESPACE_BEGIN

/* Blender Camera Intermediate: we first convert both the offline and 3d view
 * render camera to this, and from there convert to our native camera format. */

struct BlenderCamera {
	float nearclip;
	float farclip;

	bool ortho;
	float ortho_scale;

	float lens;
	float lensradius;
	float focaldistance;

	float2 shift;
	float2 offset;
	float zoom;

	float2 pixelaspect;

	Transform matrix;
};

static void blender_camera_init(BlenderCamera *bcam)
{
	memset(bcam, 0, sizeof(BlenderCamera));

	bcam->zoom = 1.0f;
	bcam->pixelaspect = make_float2(1.0f, 1.0f);
}

static float blender_camera_focal_distance(BL::Object b_ob, BL::Camera b_camera)
{
	BL::Object b_dof_object = b_camera.dof_object();

	if(!b_dof_object)
		return b_camera.dof_distance();
	
	/* for dof object, return distance along camera direction. this is
	 * compatible with blender, but does it fit our dof model? */
	Transform obmat = get_transform(b_ob.matrix_world());
	Transform dofmat = get_transform(b_dof_object.matrix_world());

	float3 cam_p = transform_get_column(&obmat, 3);
	float3 cam_dir = normalize(transform_get_column(&obmat, 2));
	float3 dof_p = transform_get_column(&dofmat, 3);
	float3 proj_p = dot(dof_p, cam_dir) * cam_dir;

	return len(proj_p - cam_p);
}

static void blender_camera_from_object(BlenderCamera *bcam, BL::Object b_ob)
{
	BL::ID b_ob_data = b_ob.data();

	if(b_ob_data.is_a(&RNA_Camera)) {
		BL::Camera b_camera(b_ob_data);
		PointerRNA ccamera = RNA_pointer_get(&b_camera.ptr, "cycles");

		bcam->nearclip = b_camera.clip_start();
		bcam->farclip = b_camera.clip_end();

		bcam->ortho = (b_camera.type() == BL::Camera::type_ORTHO);
		bcam->ortho_scale = b_camera.ortho_scale();

		bcam->lens = b_camera.lens();
		bcam->lensradius = RNA_float_get(&ccamera, "lens_radius");
		bcam->focaldistance = blender_camera_focal_distance(b_ob, b_camera);

		bcam->shift.x = b_camera.shift_x();
		bcam->shift.y = b_camera.shift_y();
	}
	else {
		/* from lamp not implemented yet */
	}
}

static void blender_camera_sync(Camera *cam, BlenderCamera *bcam, int width, int height)
{
	/* copy camera to compare later */
	Camera prevcam = *cam;

	/* dimensions */
	float xratio = width*bcam->pixelaspect.x;
	float yratio = height*bcam->pixelaspect.y;

	/* compute x/y aspect and ratio */
	float aspectratio, xaspect, yaspect;

	if(xratio > yratio) {
		aspectratio= xratio/yratio;
		xaspect= aspectratio;
		yaspect= 1.0f;
	}
	else {
		aspectratio= yratio/xratio;
		xaspect= 1.0f;
		yaspect= aspectratio;
	}

	/* modify aspect for orthographic scale */
	if(bcam->ortho) {
		xaspect = xaspect*bcam->ortho_scale/(aspectratio*2.0f);
		yaspect = yaspect*bcam->ortho_scale/(aspectratio*2.0f);
		aspectratio = bcam->ortho_scale/2.0f;
	}

	/* set viewplane */
	cam->left = -xaspect;
	cam->right = xaspect;
	cam->bottom = -yaspect;
	cam->top = yaspect;

	/* zoom for 3d camera view */
	cam->left *= bcam->zoom;
	cam->right *= bcam->zoom;
	cam->bottom *= bcam->zoom;
	cam->top *= bcam->zoom;

	/* modify viewplane with camera shift and 3d camera view offset */
	float dx = 2.0f*(aspectratio*bcam->shift.x + bcam->offset.x*xaspect*2.0f);
	float dy = 2.0f*(aspectratio*bcam->shift.y + bcam->offset.y*yaspect*2.0f);

	cam->left += dx;
	cam->right += dx;
	cam->bottom += dy;
	cam->top += dy;

	/* clipping distances */
	cam->nearclip = bcam->nearclip;
	cam->farclip = bcam->farclip;

	/* orthographic */
	cam->ortho = bcam->ortho;

	/* perspective */
	cam->fov = 2.0f*atan(16.0f/bcam->lens/aspectratio);
	cam->focaldistance = bcam->focaldistance;
	cam->lensradius = bcam->lensradius;

	/* transform, note the blender camera points along the negative z-axis */
	cam->matrix = bcam->matrix * transform_scale(1.0f, 1.0f, -1.0f);

	/* set update flag */
	if(cam->modified(prevcam))
		cam->tag_update();
}

/* Sync Render Camera */

void BlenderSync::sync_camera(int width, int height)
{
	BlenderCamera bcam;
	blender_camera_init(&bcam);

	/* pixel aspect */
	BL::RenderSettings r = b_scene.render();

	bcam.pixelaspect.x = r.pixel_aspect_x();
	bcam.pixelaspect.y = r.pixel_aspect_y();

	/* camera object */
	BL::Object b_ob = b_scene.camera();

	if(b_ob) {
		blender_camera_from_object(&bcam, b_ob);
		bcam.matrix = get_transform(b_ob.matrix_world());
	}

	/* sync */
	Camera *cam = scene->camera;
	blender_camera_sync(cam, &bcam, width, height);
}

/* Sync 3D View Camera */

void BlenderSync::sync_view(BL::SpaceView3D b_v3d, BL::RegionView3D b_rv3d, int width, int height)
{
	BlenderCamera bcam;
	blender_camera_init(&bcam);

	/* 3d view parameters */
	bcam.nearclip = b_v3d.clip_start();
	bcam.farclip = b_v3d.clip_end();
	bcam.lens = b_v3d.lens();

	if(b_rv3d.view_perspective() == BL::RegionView3D::view_perspective_CAMERA) {
		/* camera view */
		BL::Object b_ob = b_scene.camera();

		if(b_ob) {
			blender_camera_from_object(&bcam, b_ob);

			/* magic zoom formula */
			bcam.zoom = (float)b_rv3d.view_camera_zoom();
			bcam.zoom = (1.41421f + bcam.zoom/50.0f);
			bcam.zoom *= bcam.zoom;
			bcam.zoom = 2.0f/bcam.zoom;

			/* offset */
			bcam.offset = get_float2(b_rv3d.view_camera_offset());
		}
	}
	else if(b_rv3d.view_perspective() == BL::RegionView3D::view_perspective_ORTHO) {
		/* orthographic view */
		bcam.farclip *= 0.5;
		bcam.nearclip = -bcam.farclip;

		bcam.ortho = true;
		bcam.ortho_scale = b_rv3d.view_distance();
	}

	bcam.zoom *= 2.0f;

	/* 3d view transform */
	bcam.matrix = transform_inverse(get_transform(b_rv3d.view_matrix()));

	/* sync */
	blender_camera_sync(scene->camera, &bcam, width, height);
}

CCL_NAMESPACE_END