/*****************************************************************************
                    The Dark Mod GPL Source Code
 
 This file is part of the The Dark Mod Source Code, originally based 
 on the Doom 3 GPL Source Code as published in 2011.
 
 The Dark Mod Source Code 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 3 of the License, 
 or (at your option) any later version. For details, see LICENSE.TXT.
 
 Project: The Dark Mod (http://www.thedarkmod.com/)
 
 $Revision: 5383 $ (Revision of last commit) 
 $Date: 2012-04-11 11:46:32 +0200 (Mi, 11 Apr 2012) $ (Date of last commit)
 $Author: serpentine $ (Author of last commit)
 
******************************************************************************/

#include "precompiled_engine.h"
#pragma hdrstop

static bool versioned = RegisterVersionedFile("$Id: tr_subview.cpp 5383 2012-04-11 09:46:32Z serpentine $");

#include "tr_local.h"


typedef struct {
	idVec3		origin;
	idMat3		axis;
} orientation_t;


/*
=================
R_MirrorPoint
=================
*/
static void R_MirrorPoint( const idVec3 in, orientation_t *surface, orientation_t *camera, idVec3 &out ) {
	int		i;
	idVec3	local;
	idVec3	transformed;
	float	d;

	local = in - surface->origin;

	transformed = vec3_origin;
	for ( i = 0 ; i < 3 ; i++ ) {
		d = local * surface->axis[i];
		transformed += d * camera->axis[i];
	}

	out = transformed + camera->origin;
}

/*
=================
R_MirrorVector
=================
*/
static void R_MirrorVector( const idVec3 in, orientation_t *surface, orientation_t *camera, idVec3 &out ) {
	int		i;
	float	d;

	out = vec3_origin;
	for ( i = 0 ; i < 3 ; i++ ) {
		d = in * surface->axis[i];
		out += d * camera->axis[i];
	}
}

/*
=============
R_PlaneForSurface

Returns the plane for the first triangle in the surface
FIXME: check for degenerate triangle?
=============
*/
static void R_PlaneForSurface( const srfTriangles_t *tri, idPlane &plane ) {
	idDrawVert		*v1, *v2, *v3;

	v1 = tri->verts + tri->indexes[0];
	v2 = tri->verts + tri->indexes[1];
	v3 = tri->verts + tri->indexes[2];
	plane.FromPoints( v1->xyz, v2->xyz, v3->xyz );
}

/*
=========================
R_PreciseCullSurface

Check the surface for visibility on a per-triangle basis
for cases when it is going to be VERY expensive to draw (subviews)

If not culled, also returns the bounding box of the surface in 
Normalized Device Coordinates, so it can be used to crop the scissor rect.

OPTIMIZE: we could also take exact portal passing into consideration
=========================
*/
bool R_PreciseCullSurface( const drawSurf_t *drawSurf, idBounds &ndcBounds ) {
	const srfTriangles_t *tri;
	int numTriangles;
	idPlane clip, eye;
	unsigned int pointOr;
	unsigned int pointAnd;
	idVec3 localView;
	idFixedWinding w;

	tri = drawSurf->geo;

	pointOr = 0;
	pointAnd = (unsigned int)~0;

	// get an exact bounds of the triangles for scissor cropping
	ndcBounds.Clear();

	for ( int i = 0; i < tri->numVerts; i++ ) {
		unsigned int pointFlags;

		R_TransformModelToClip( tri->verts[i].xyz, drawSurf->space->modelViewMatrix,
			tr.viewDef->projectionMatrix, eye, clip );

		pointFlags = 0;
		for ( int j = 0; j < 3; j++ ) {
			if ( clip[j] >= clip[3] ) {
				pointFlags |= (1 << (j*2));
			} else if ( clip[j] <= -clip[3] ) {
				pointFlags |= ( 1 << (j*2+1));
			}
		}

		pointAnd &= pointFlags;
		pointOr |= pointFlags;
	}

	// trivially reject
	if ( pointAnd ) {
		return true;
	}

	// backface and frustum cull
	numTriangles = tri->numIndexes / 3;

	R_GlobalPointToLocal( drawSurf->space->modelMatrix, tr.viewDef->renderView.vieworg, localView );

	for ( int i = 0; i < tri->numIndexes; i += 3 ) {
		idVec3	dir, normal;
		float	dot;
		idVec3	d1, d2;

		const idVec3 &v1 = tri->verts[tri->indexes[i]].xyz;
		const idVec3 &v2 = tri->verts[tri->indexes[i+1]].xyz;
		const idVec3 &v3 = tri->verts[tri->indexes[i+2]].xyz;

		// this is a hack, because R_GlobalPointToLocal doesn't work with the non-normalized
		// axis that we get from the gui view transform.  It doesn't hurt anything, because
		// we know that all gui generated surfaces are front facing
		if ( tr.guiRecursionLevel == 0 ) {
			// we don't care that it isn't normalized,
			// all we want is the sign
			d1 = v2 - v1;
			d2 = v3 - v1;
			normal = d2.Cross( d1 );

			dir = v1 - localView;

			dot = normal * dir;
			if ( dot >= 0.0f ) {
				return true;
			}
		}

		// now find the exact screen bounds of the clipped triangle
		w.SetNumPoints( 3 );
		R_LocalPointToGlobal( drawSurf->space->modelMatrix, v1, w[0].ToVec3() );
		R_LocalPointToGlobal( drawSurf->space->modelMatrix, v2, w[1].ToVec3() );
		R_LocalPointToGlobal( drawSurf->space->modelMatrix, v3, w[2].ToVec3() );
		w[0].s = w[0].t = w[1].s = w[1].t = w[2].s = w[2].t = 0.0f;

		for ( int j = 0; j < 4; j++ ) {
			if ( !w.ClipInPlace( -tr.viewDef->frustum[j], 0.1f ) ) {
				break;
			}
		}
		for ( int j = 0; j < w.GetNumPoints(); j++ ) {
			idVec3	screen;

			R_GlobalToNormalizedDeviceCoordinates( w[j].ToVec3(), screen );
			ndcBounds.AddPoint( screen );
		}
	}

	// if we don't enclose any area, return
	if ( ndcBounds.IsCleared() ) {
		return true;
	}

	return false;
}

/*
========================
R_MirrorViewBySurface
========================
*/
static viewDef_t *R_MirrorViewBySurface( drawSurf_t *drawSurf ) {
	viewDef_t		*parms;
	orientation_t	surface, camera;
	idPlane			originalPlane, plane;

	// copy the viewport size from the original
	parms = (viewDef_t *)R_FrameAlloc( sizeof( *parms ) );
	*parms = *tr.viewDef;
	parms->renderView.viewID = 0;	// clear to allow player bodies to show up, and suppress view weapons

	parms->isSubview = true;
	parms->isMirror = true;

	// create plane axis for the portal we are seeing
	R_PlaneForSurface( drawSurf->geo, originalPlane );
	R_LocalPlaneToGlobal( drawSurf->space->modelMatrix, originalPlane, plane );

	surface.origin = plane.Normal() * -plane[3];
	surface.axis[0] = plane.Normal();
	surface.axis[0].NormalVectors( surface.axis[1], surface.axis[2] );
	surface.axis[2] = -surface.axis[2];

	camera.origin = surface.origin;
	camera.axis[0] = -surface.axis[0];
	camera.axis[1] = surface.axis[1];
	camera.axis[2] = surface.axis[2];

	// set the mirrored origin and axis
	R_MirrorPoint( tr.viewDef->renderView.vieworg, &surface, &camera, parms->renderView.vieworg );

	R_MirrorVector( tr.viewDef->renderView.viewaxis[0], &surface, &camera, parms->renderView.viewaxis[0] );
	R_MirrorVector( tr.viewDef->renderView.viewaxis[1], &surface, &camera, parms->renderView.viewaxis[1] );
	R_MirrorVector( tr.viewDef->renderView.viewaxis[2], &surface, &camera, parms->renderView.viewaxis[2] );

	// make the view origin 16 units away from the center of the surface
	idVec3	viewOrigin = ( drawSurf->geo->bounds[0] + drawSurf->geo->bounds[1] ) * 0.5;
	viewOrigin += ( originalPlane.Normal() * 16 );

	R_LocalPointToGlobal( drawSurf->space->modelMatrix, viewOrigin, parms->initialViewAreaOrigin );

	// set the mirror clip plane
	parms->numClipPlanes = 1;
	parms->clipPlanes[0] = -camera.axis[0];

	parms->clipPlanes[0][3] = -( camera.origin * parms->clipPlanes[0].Normal() );
	
	return parms;
}

/*
========================
R_XrayViewBySurface
========================
*/
static viewDef_t *R_XrayViewBySurface( drawSurf_t *drawSurf ) {
	viewDef_t		*parms;
	orientation_t	surface, camera;
	idPlane			originalPlane, plane;

	// copy the viewport size from the original
	parms = (viewDef_t *)R_FrameAlloc( sizeof( *parms ) );
	*parms = *tr.viewDef;
	parms->renderView.viewID = 0;	// clear to allow player bodies to show up, and suppress view weapons

	parms->isSubview = true;
	parms->isXraySubview = true;

	return parms;
}

/*
===============
R_RemoteRender
===============
*/
static void R_RemoteRender( drawSurf_t *surf, textureStage_t *stage ) {
	viewDef_t		*parms;

	// remote views can be reused in a single frame
	if ( stage->dynamicFrameCount == tr.frameCount ) {
		return;
	}

	// if the entity doesn't have a remoteRenderView, do nothing
	if ( !surf->space->entityDef->parms.remoteRenderView ) {
		return;
	}

	// copy the viewport size from the original
	parms = (viewDef_t *)R_FrameAlloc( sizeof( *parms ) );
	*parms = *tr.viewDef;

	parms->isSubview = true;
	parms->isMirror = false;

	parms->renderView = *surf->space->entityDef->parms.remoteRenderView;
	parms->renderView.viewID = 0;	// clear to allow player bodies to show up, and suppress view weapons
	parms->initialViewAreaOrigin = parms->renderView.vieworg;

	tr.CropRenderSize( stage->width, stage->height, true );

	parms->renderView.x = 0;
	parms->renderView.y = 0;
	parms->renderView.width = SCREEN_WIDTH;
	parms->renderView.height = SCREEN_HEIGHT;

	tr.RenderViewToViewport( &parms->renderView, &parms->viewport );

	parms->scissor.x1 = 0;
	parms->scissor.y1 = 0;
	parms->scissor.x2 = parms->viewport.x2 - parms->viewport.x1;
	parms->scissor.y2 = parms->viewport.y2 - parms->viewport.y1;

	parms->superView = tr.viewDef;
	parms->subviewSurface = surf;

	// generate render commands for it
	R_RenderView(parms);

	// copy this rendering to the image
	stage->dynamicFrameCount = tr.frameCount;
	if (!stage->image) {
		stage->image = globalImages->scratchImage;
	}

	tr.CaptureRenderToImage( stage->image->imgName );
	tr.UnCrop();
}

/*
=================
R_MirrorRender
=================
*/
void R_MirrorRender( drawSurf_t *surf, textureStage_t *stage, idScreenRect scissor ) {
	viewDef_t		*parms;

	// remote views can be reused in a single frame
	if ( stage->dynamicFrameCount == tr.frameCount ) {
		return;
	}

	// issue a new view command
	parms = R_MirrorViewBySurface( surf );
	if ( !parms ) {
		return;
	}

	tr.CropRenderSize( stage->width, stage->height, true );

	parms->renderView.x = 0;
	parms->renderView.y = 0;
	parms->renderView.width = SCREEN_WIDTH;
	parms->renderView.height = SCREEN_HEIGHT;

	tr.RenderViewToViewport( &parms->renderView, &parms->viewport );

	parms->scissor.x1 = 0;
	parms->scissor.y1 = 0;
	parms->scissor.x2 = parms->viewport.x2 - parms->viewport.x1;
	parms->scissor.y2 = parms->viewport.y2 - parms->viewport.y1;

	parms->superView = tr.viewDef;
	parms->subviewSurface = surf;

	// triangle culling order changes with mirroring
	parms->isMirror = ( ( (int)parms->isMirror ^ (int)tr.viewDef->isMirror ) != 0 );

	// generate render commands for it
	R_RenderView( parms );

	// copy this rendering to the image
	stage->dynamicFrameCount = tr.frameCount;
	stage->image = globalImages->scratchImage;

	tr.CaptureRenderToImage( stage->image->imgName );
	tr.UnCrop();
}

/*
=================
R_XrayRender
=================
*/
void R_XrayRender( drawSurf_t *surf, textureStage_t *stage, idScreenRect scissor ) {
	viewDef_t		*parms;

	// remote views can be reused in a single frame
	if ( stage->dynamicFrameCount == tr.frameCount ) {
		return;
	}

	// issue a new view command
	parms = R_XrayViewBySurface( surf );
	if ( !parms ) {
		return;
	}

	tr.CropRenderSize( stage->width, stage->height, true );

	parms->renderView.x = 0;
	parms->renderView.y = 0;
	parms->renderView.width = SCREEN_WIDTH;
	parms->renderView.height = SCREEN_HEIGHT;

	tr.RenderViewToViewport( &parms->renderView, &parms->viewport );

	parms->scissor.x1 = 0;
	parms->scissor.y1 = 0;
	parms->scissor.x2 = parms->viewport.x2 - parms->viewport.x1;
	parms->scissor.y2 = parms->viewport.y2 - parms->viewport.y1;

	parms->superView = tr.viewDef;
	parms->subviewSurface = surf;

	// triangle culling order changes with mirroring
	parms->isMirror = ( ( (int)parms->isMirror ^ (int)tr.viewDef->isMirror ) != 0 );

	// generate render commands for it
	R_RenderView( parms );

	// copy this rendering to the image
	stage->dynamicFrameCount = tr.frameCount;
	stage->image = globalImages->scratchImage2;

	tr.CaptureRenderToImage( stage->image->imgName );
	tr.UnCrop();
}

/*
==================
R_GenerateSurfaceSubview
==================
*/
bool	R_GenerateSurfaceSubview( drawSurf_t *drawSurf ) {
	idBounds		ndcBounds;
	viewDef_t		*parms;
	const idMaterial		*shader;

	// for testing the performance hit
	if ( r_skipSubviews.GetBool() ) {
		return false;
	}

	if ( R_PreciseCullSurface( drawSurf, ndcBounds ) ) {
		return false;
	}

	shader = drawSurf->material;

	// never recurse through a subview surface that we are
	// already seeing through
	for ( parms = tr.viewDef ; parms ; parms = parms->superView ) {
		if ( parms->subviewSurface
			&& parms->subviewSurface->geo == drawSurf->geo
			&& parms->subviewSurface->space->entityDef == drawSurf->space->entityDef ) {
			break;
		}
	}
	if ( parms ) {
		return false;
	}

	// crop the scissor bounds based on the precise cull
	idScreenRect	scissor;

	idScreenRect	*v = &tr.viewDef->viewport;
	scissor.x1 = v->x1 + (int)( (v->x2 - v->x1 + 1 ) * 0.5f * ( ndcBounds[0][0] + 1.0f ));
	scissor.y1 = v->y1 + (int)( (v->y2 - v->y1 + 1 ) * 0.5f * ( ndcBounds[0][1] + 1.0f ));
	scissor.x2 = v->x1 + (int)( (v->x2 - v->x1 + 1 ) * 0.5f * ( ndcBounds[1][0] + 1.0f ));
	scissor.y2 = v->y1 + (int)( (v->y2 - v->y1 + 1 ) * 0.5f * ( ndcBounds[1][1] + 1.0f ));

	// nudge a bit for safety
	scissor.Expand();

	scissor.Intersect( tr.viewDef->scissor );

	if ( scissor.IsEmpty() ) {
		// cropped out
		return false;
	}

	// see what kind of subview we are making
	if ( shader->GetSort() != SS_SUBVIEW ) {
		for ( int i = 0 ; i < shader->GetNumStages() ; i++ ) {
			const shaderStage_t	*stage = shader->GetStage( i );
			switch ( stage->texture.dynamic ) {
			case DI_REMOTE_RENDER:
				R_RemoteRender( drawSurf, const_cast<textureStage_t *>(&stage->texture) );
				break;
			case DI_MIRROR_RENDER:
				R_MirrorRender( drawSurf, const_cast<textureStage_t *>(&stage->texture), scissor );
				break;
			case DI_XRAY_RENDER:
				R_XrayRender( drawSurf, const_cast<textureStage_t *>(&stage->texture), scissor );
				break;
			}
		}
		return true;
	}

	// issue a new view command
	parms = R_MirrorViewBySurface( drawSurf );
	if ( !parms ) {
		return false;
	}

	parms->scissor = scissor;
	parms->superView = tr.viewDef;
	parms->subviewSurface = drawSurf;

	// triangle culling order changes with mirroring
	parms->isMirror = ( ( (int)parms->isMirror ^ (int)tr.viewDef->isMirror ) != 0 );

	// generate render commands for it
	R_RenderView( parms );

	return true;
}

/*
================
R_GenerateSubViews

If we need to render another view to complete the current view,
generate it first.

It is important to do this after all drawSurfs for the current
view have been generated, because it may create a subview which
would change tr.viewCount.
================
*/
bool R_GenerateSubViews( void ) {
	drawSurf_t		*drawSurf;
	int				i;
	bool			subviews;
	const idMaterial		*shader;

	// for testing the performance hit
	if ( r_skipSubviews.GetBool() ) {
		return false;
	}

	subviews = false;

	// scan the surfaces until we either find a subview, or determine
	// there are no more subview surfaces.
	for ( i = 0 ; i < tr.viewDef->numDrawSurfs ; i++ ) {
		drawSurf = tr.viewDef->drawSurfs[i];
		shader = drawSurf->material;

		if ( !shader || !shader->HasSubview() ) {
			continue;
		}

		if ( R_GenerateSurfaceSubview( drawSurf ) ) {
			subviews = true;
		}
	}

	return subviews;
}
