/* writevrml.c: saves the result of a radiosity computation as a VRML file. */

#include "writevrml.h"
#include "scene.h"
#include "defaults.h"
#include "camera.h"
#include "render.h"
#include "error.h"

/* compute a rotation that will rotate the current "up"-direction to the Y axis.
 * Y-axis points up in VRML2.0 */
TRANSFORM VRMLModelTransform(VECTOR *model_rotaxis, float *model_rotangle)
{
  VECTOR up_axis;
  double cosa;

  VECTORSET(up_axis, 0., 1., 0.);
  cosa = VECTORDOTPRODUCT(Camera.updir, up_axis);
  if (cosa < 1. - EPSILON) {
    *model_rotangle = acos(cosa);
    VECTORCROSSPRODUCT(Camera.updir, up_axis, *model_rotaxis);
    VECTORNORMALIZE(*model_rotaxis);
    return Rotate(*model_rotangle, *model_rotaxis);
  } else {
    VECTORSET(*model_rotaxis, 0., 1., 0.);
    *model_rotangle = 0.;
    return IdentityTransform;
  }
}

/* Write VRML ViewPoint node for the given camera position */
void WriteVRMLViewPoint(FILE *fp, TRANSFORM model_xf, CAMERA *cam, char *vpname)
{
  VECTOR X, Y, Z, view_rotaxis, eyep;
  TRANSFORM view_xf;
  float view_rotangle;

  VECTORSCALE( 1., cam->X, X); /* cam->X points right in window */
  VECTORSCALE(-1., cam->Y, Y); /* cam->Y points down in window, VRML wants y up */
  VECTORSCALE(-1., cam->Z, Z); /* cam->Z points away, VRML wants Z to point towards viewer */

  /* apply model transform */
  TRANSFORM_VECTOR_3D(model_xf, X, X);
  TRANSFORM_VECTOR_3D(model_xf, Y, Y);
  TRANSFORM_VECTOR_3D(model_xf, Z, Z);

  /* construct view orientation transform and recover axis and angle */
  view_xf = IdentityTransform;
  SET_3X3MATRIX(view_xf.m,
		X.x, Y.x, Z.x,
		X.y, Y.y, Z.y,
		X.z, Y.z, Z.z);
  RecoverRotation(view_xf, &view_rotangle, &view_rotaxis);

  /* apply model transform to eye point */
  TRANSFORM_POINT_3D(model_xf, cam->eyep, eyep);

  fprintf(fp, "Viewpoint {\n  position %g %g %g\n  orientation %g %g %g %g\n  fieldOfView %g\n  description \"%s\"\n}\n\n", 
	  eyep.x, eyep.y, eyep.z,
	  view_rotaxis.x, view_rotaxis.y, view_rotaxis.z, view_rotangle,
	  (double)(2. * cam->fov * M_PI / 180.),
	  vpname);
}

void WriteVRMLViewPoints(FILE *fp, TRANSFORM model_xf)
{
  CAMERA *cam = (CAMERA *)NULL;
  int count = 1;
  WriteVRMLViewPoint(fp, model_xf, &Camera, "ViewPoint 1");
  while ((cam = NextSavedCamera(cam)) != (CAMERA *)NULL) {
    char vpname[20];
    count++; sprintf(vpname, "ViewPoint %d", count);
    WriteVRMLViewPoint(fp, model_xf, cam, vpname);
  }
}

void WriteVRMLHeader(FILE *fp)
{
  TRANSFORM model_xf;
  VECTOR model_rotaxis;
  float model_rotangle;

  fprintf(fp, "#VRML V2.0 utf8\n\n");

  fprintf(fp, "WorldInfo {\n  title \"%s\"\n  info [ \"Created using RenderPark (%s)\" ]\n}\n\n",
	  "Some nice model",
	  RPKHOME);

  fprintf(fp, "NavigationInfo {\n type \"WALK\"\n headlight FALSE\n}\n\n");

  model_xf = VRMLModelTransform(&model_rotaxis, &model_rotangle);
  WriteVRMLViewPoints(fp, model_xf);

  fprintf(fp, "Transform {\n  rotation %g %g %g %g\n  children [\n    Shape {\n      geometry IndexedFaceSet {\n",
	  model_rotaxis.x, model_rotaxis.y, model_rotaxis.z, model_rotangle);

  fprintf(fp, "\tsolid %s\n", renderopts.backface_culling ? "TRUE" : "FALSE");
}

void WriteVRMLTrailer(FILE *fp)
{
  fprintf(fp, "      }\n    }\n  ]\n}\n\n");
}

static void ResetVertexId(void)
{
  ForAllPatches(P, Patches) {
    int i;
    for (i=0; i<P->nrvertices; i++)
      P->vertex[i]->tmp = -1;
  } EndForAll;
}

static void WriteCoords(FILE *fp)
{
  int id = 0, n = 0;

  ResetVertexId();

  fprintf(fp, "\tcoord Coordinate {\n\t  point [ ");
  ForAllPatches(P, Patches) {
    int i;
    for (i=0; i<P->nrvertices; i++) {
      VERTEX *v = P->vertex[i];
      if (v->tmp == -1) {
	/* not yet written */
	if (n>0)
	  fprintf(fp, ", ");
	n++;
	if (n%4 == 0)
	  fprintf(fp, "\n\t  ");
	fprintf(fp, "%g %g %g", v->point->x, v->point->y, v->point->z);
	v->tmp = id; id++;
      }
    }
  } EndForAll;
  fprintf(fp, " ] ");
  fprintf(fp, "\n\t}\n");
}

static void WriteVertexColors(FILE *fp)
{
  int id = 0, n = 0;

  ResetVertexId();

  fprintf(fp, "\tcolor Color {\n\t  color [ ");
  ForAllPatches(P, Patches) {
    int i;
    for (i=0; i<P->nrvertices; i++) {
      VERTEX *v = P->vertex[i];
      if (v->tmp == -1) {
	/* not yet written */
	if (n>0)
	  fprintf(fp, ", ");
	n++;
	if (n%4 == 0)
	  fprintf(fp, "\n\t  ");
	fprintf(fp, "%.3g %.3g %.3g", v->color.r, v->color.g, v->color.b);
	v->tmp = id; id++;
      }
    }
  } EndForAll;
  fprintf(fp, " ] ");
  fprintf(fp, "\n\t}\n");
}

static void WriteFaceColors(FILE *fp)
{
  int n = 0;

  fprintf(fp, "\tcolor Color {\n\t  color [ ");
  ForAllPatches(P, Patches) {
    if (n>0)
      fprintf(fp, ", ");
    n++;
    if (n%4 == 0)
      fprintf(fp, "\n\t  ");
    fprintf(fp, "%.3g %.3g %.3g", P->color.r, P->color.g, P->color.b);
  } EndForAll;
  fprintf(fp, " ] ");
  fprintf(fp, "\n\t}\n");
}

static void WriteColors(FILE *fp)
{
  fprintf(fp, "\tcolorPerVertex %s\n", renderopts.smooth_shading ? "TRUE" : "FALSE");
  if (renderopts.smooth_shading)
    WriteVertexColors(fp);
  else
    WriteFaceColors(fp);
}

static void WriteCoordIndices(FILE *fp)
{
  int n=0;
  fprintf(fp, "\tcoordIndex [ ");
  ForAllPatches(P, Patches) {
    int i;
    for (i=0; i<P->nrvertices; i++) {
      VERTEX *v = P->vertex[i];
      n++;
      if (n%20 == 0) fprintf(fp, "\n\t  ");
      fprintf(fp, "%d ", v->tmp);
    }
    n++;
    if (n%20 == 0) fprintf(fp, "\n\t  ");
    fprintf(fp, "-1 ");
  } EndForAll;
  fprintf(fp, " ]\n");
}

void WriteVRML(FILE *fp)
{
  WriteVRMLHeader(fp);

  WriteCoords(fp);
  WriteColors(fp);
  WriteCoordIndices(fp);

  WriteVRMLTrailer(fp);
}