#include "tr_local.h"

/*

All bones should be an identity orientation to display the mesh exactly
as it is specified.

For all other frames, the bones represent the transformation from the 
orientation of the bone in the base frame to the orientation in this
frame.

*/

/*
==============
R_AddAnimSurfaces
==============
*/
void R_AddAnimSurfaces( trRefEntity_t *ent ) {
	md4Header_t		*header;
	md4Surface_t	*surface;
	md4LOD_t		*lod;
	shader_t		*shader;
	int				i;

	header = tr.currentModel->md4;
	lod = (md4LOD_t *)( (byte *)header + header->ofsLODs );

	surface = (md4Surface_t *)( (byte *)lod + lod->ofsSurfaces );
	for ( i = 0 ; i < lod->numSurfaces ; i++ ) {
		shader = R_GetShaderByHandle( surface->shaderIndex );
		R_AddDrawSurf( (surfaceType_t *)surface, shader, 0 /*fogNum*/, qfalse );
		surface = (md4Surface_t *)( (byte *)surface + surface->ofsEnd );
	}
}


/*
==============
RB_SurfaceAnim
==============
*/
void RB_SurfaceAnim( md4Surface_t *surface ) {
	int				i, j, k;
	float			frontlerp, backlerp;
	int				*triangles;
	int				indexes;
	int				baseIndex, baseVertex;
	int				numVerts;
	md4Vertex_t		*v;
	md4Bone_t		bones[MD4_MAX_BONES];
	md4Bone_t		*bonePtr, *bone;
	md4Header_t		*header;
	md4Frame_t		*frame;
	md4Frame_t		*oldFrame;
	int				frameSize;


	if (  backEnd.currentEntity->e.oldframe == backEnd.currentEntity->e.frame ) {
		backlerp = 0;
		frontlerp = 1;
	} else  {
		backlerp = backEnd.currentEntity->e.backlerp;
		frontlerp = 1.0f - backlerp;
	}
	header = (md4Header_t *)((byte *)surface + surface->ofsHeader);

	frameSize = (int)( &((md4Frame_t *)0)->bones[ header->numBones ] );

	frame = (md4Frame_t *)((byte *)header + header->ofsFrames + 
		backEnd.currentEntity->e.frame * frameSize );
	oldFrame = (md4Frame_t *)((byte *)header + header->ofsFrames + 
		backEnd.currentEntity->e.oldframe * frameSize );

	RB_CheckOverflow( surface->numVerts, surface->numTriangles * 3 );

	triangles = (int *) ((byte *)surface + surface->ofsTriangles);
	indexes = surface->numTriangles * 3;
	baseIndex = tess.numIndexes;
	baseVertex = tess.numVertexes;
	for (j = 0 ; j < indexes ; j++) {
		tess.indexes[baseIndex + j] = baseIndex + triangles[j];
	}
	tess.numIndexes += indexes;

	//
	// lerp all the needed bones
	//
	if ( !backlerp ) {
		// no lerping needed
		bonePtr = frame->bones;
	} else {
		bonePtr = bones;
		for ( i = 0 ; i < header->numBones*12 ; i++ ) {
			((float *)bonePtr)[i] = frontlerp * ((float *)frame->bones)[i]
				+ backlerp * ((float *)oldFrame->bones)[i];
		}
	}

	//
	// deform the vertexes by the lerped bones
	//
	numVerts = surface->numVerts;
	v = (md4Vertex_t *) ((byte *)surface + surface->ofsVerts);
	for ( j = 0; j < numVerts; j++ ) {
		vec3_t	tempVert, tempNormal;
		md4Weight_t	*w;

		VectorClear( tempVert );
		VectorClear( tempNormal );
		w = v->weights;
		for ( k = 0 ; k < v->numWeights ; k++, w++ ) {
			bone = bonePtr + w->boneIndex;

			tempVert[0] += w->boneWeight * ( DotProduct( bone->matrix[0], w->offset ) + bone->matrix[0][3] );
			tempVert[1] += w->boneWeight * ( DotProduct( bone->matrix[1], w->offset ) + bone->matrix[1][3] );
			tempVert[2] += w->boneWeight * ( DotProduct( bone->matrix[2], w->offset ) + bone->matrix[2][3] );

			tempNormal[0] += w->boneWeight * DotProduct( bone->matrix[0], v->normal );
			tempNormal[1] += w->boneWeight * DotProduct( bone->matrix[1], v->normal );
			tempNormal[2] += w->boneWeight * DotProduct( bone->matrix[2], v->normal );
		}

		tess.xyz[baseVertex + j][0] = tempVert[0];
		tess.xyz[baseVertex + j][1] = tempVert[1];
		tess.xyz[baseVertex + j][2] = tempVert[2];

		tess.normal[baseVertex + j][0] = tempNormal[0];
		tess.normal[baseVertex + j][1] = tempNormal[1];
		tess.normal[baseVertex + j][2] = tempNormal[2];

		tess.texCoords[baseVertex + j][0][0] = v->texCoords[0];
		tess.texCoords[baseVertex + j][0][1] = v->texCoords[1];

		v = (md4Vertex_t *)&v->weights[v->numWeights];
	}

	tess.numVertexes += surface->numVerts;
}