QNAN

The ODE demos run with the Z-axis as being up/down. I have tried to change this to work with my system, where Y-axis is up/down.

 

I got it to work with a heightfield. Unfortunately, there is an unfixed bug in the heightfield, so it will fail in certain areas. The solution is to use a tri-mesh.

 

So I took a look at the trimesh-demo to learn how to convert my heightmap data to an ODE trimesh. After failing again and again, I finally went to the root and tried to convert the ODE trimesh itself to use a gravity vector of -Y instead of -Z as it has now, while at the same time changing the trimesh to the new orientation.

I believe I have translated everything correctly, but the demo still fails, and behaves quite like the test in my own program.

 

I will write the entire file here.

Search for "Y-Conversion" to find the areas I changed from the original.

The original can be seen commented out at the bottom.

The easiest would probably be to substitute this one with the original while testing, if you have the ODE system installed.

 

Is ODE only working with Z-axis or did I miss something in conversion?

 

Here is the code (I couldn't attach a .cpp?)

/*************************************************************************
 *                                                                       *
 * Open Dynamics Engine, Copyright (C) 2001-2003 Russell L. Smith.       *
 * All rights reserved.  Email: russ@q12.org   Web: www.q12.org          *
 *                                                                       *
 * This library is free software; you can redistribute it and/or         *
 * modify it under the terms of EITHER:                                  *
 *   (1) The GNU Lesser General Public License as published by the Free  *
 *       Software Foundation; either version 2.1 of the License, or (at  *
 *       your option) any later version. The text of the GNU Lesser      *
 *       General Public License is included with this library in the     *
 *       file LICENSE.TXT.                                               *
 *   (2) The BSD-style license that is included with this library in     *
 *       the file LICENSE-BSD.TXT.                                       *
 *                                                                       *
 * This library 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 files    *
 * LICENSE.TXT and LICENSE-BSD.TXT for more details.                     *
 *                                                                       *
 *************************************************************************/

// TriMesh test by Erwin de Vries

#include <ode/ode.h>
#include <drawstuff/drawstuff.h>
#include "texturepath.h"

#ifdef _MSC_VER
#pragma warning(disable:4244 4305)  // for VC++, no precision loss complaints
#endif

// select correct drawing functions

#ifdef dDOUBLE
#define dsDrawBox dsDrawBoxD
#define dsDrawSphere dsDrawSphereD
#define dsDrawCylinder dsDrawCylinderD
#define dsDrawCapsule dsDrawCapsuleD
#define dsDrawLine dsDrawLineD
#define dsDrawTriangle dsDrawTriangleD
#endif


// some constants

#define NUM 200			// max number of objects
#define DENSITY (5.0)		// density of all objects
#define GPB 3			// maximum number of geometries per body
#define MAX_CONTACTS 40		// maximum number of contact points per body


// dynamics and collision objects

struct MyObject {
  dBodyID body;			// the body
  dGeomID geom[GPB];		// geometries representing this body
};

static int num=0;		// number of objects in simulation
static int nextobj=0;		// next object to recycle if num==NUM
static dWorldID world;
static dSpaceID space;
static MyObject obj[NUM];
static dJointGroupID contactgroup;
static int selected = -1;	// selected object
static int show_aabb = 0;	// show geom AABBs?
static int show_contacts = 0;	// show contact points?
static int random_pos = 1;	// drop objects from random position?

#define VertexCount 5
#define IndexCount 12

static dVector3 Size;
static float Vertices[VertexCount][3];
static dTriIndex Indices[IndexCount];

static dGeomID TriMesh;
static dGeomID Ray;


// this is called by dSpaceCollide when two objects in space are
// potentially colliding.

static void nearCallback (void *data, dGeomID o1, dGeomID o2)
{
  int i;
  // if (o1->body && o2->body) return;

  // exit without doing anything if the two bodies are connected by a joint
  dBodyID b1 = dGeomGetBody(o1);
  dBodyID b2 = dGeomGetBody(o2);
  if (b1 && b2 && dAreConnectedExcluding (b1,b2,dJointTypeContact)) return;

  dContact contact[MAX_CONTACTS];   // up to MAX_CONTACTS contacts per box-box
  for (i=0; i<MAX_CONTACTS; i++) {
    contact[i].surface.mode = dContactBounce | dContactSoftCFM;
    contact[i].surface.mu = dInfinity;
    contact[i].surface.mu2 = 0;
    contact[i].surface.bounce = 0.1;
    contact[i].surface.bounce_vel = 0.1;
    contact[i].surface.soft_cfm = 0.01;
  }
  if (int numc = dCollide (o1,o2,MAX_CONTACTS,&contact[0].geom,
			   sizeof(dContact))) {
    dMatrix3 RI;
    dRSetIdentity (RI);
    const dReal ss[3] = {0.02,0.02,0.02};
    for (i=0; i<numc; i++) {
		if (dGeomGetClass(o1) == dRayClass || dGeomGetClass(o2) == dRayClass){
			dMatrix3 Rotation;
			dRSetIdentity(Rotation);
			dsDrawSphere(contact[i].geom.pos, Rotation, REAL(0.01));
			
			dVector3 End;
			End[0] = contact[i].geom.pos[0] + (contact[i].geom.normal[0] * contact[i].geom.depth);
			End[1] = contact[i].geom.pos[1] + (contact[i].geom.normal[1] * contact[i].geom.depth);
			End[2] = contact[i].geom.pos[2] + (contact[i].geom.normal[2] * contact[i].geom.depth);
			End[3] = contact[i].geom.pos[3] + (contact[i].geom.normal[3] * contact[i].geom.depth);
			
			dsDrawLine(contact[i].geom.pos, End);
			continue;
		}
		
      dJointID c = dJointCreateContact (world,contactgroup,contact+i);
      dJointAttach (c,b1,b2);
      if (show_contacts) dsDrawBox (contact[i].geom.pos,RI,ss);
    }
  }
}


// start simulation - set viewpoint

static void start()
{
  dAllocateODEDataForThread(dAllocateMaskAll);

  static float xyz[3] = {2.1640f,-1.3079f,1.7600f};
  static float hpr[3] = {125.5000f,-17.0000f,0.0000f};
  dsSetViewpoint (xyz,hpr);
  printf ("To drop another object, press:\n");
  printf ("   b for box.\n");
  printf ("   s for sphere.\n");
  printf ("   c for cylinder.\n");
  printf ("   x for a composite object.\n");
  printf ("To select an object, press space.\n");
  printf ("To disable the selected object, press d.\n");
  printf ("To enable the selected object, press e.\n");
  printf ("To toggle showing the geom AABBs, press a.\n");
  printf ("To toggle showing the contact points, press t.\n");
  printf ("To toggle dropping from random position/orientation, press r.\n");
}


char locase (char c)
{
  if (c >= 'A' && c <= 'Z') return c - ('a'-'A');
  else return c;
}


// called when a key pressed

static void command (int cmd)
{
  int i,j,k;
  dReal sides[3];
  dMass m;

  cmd = locase (cmd);
  if (cmd == 'b' || cmd == 's' || cmd == 'c' || cmd == 'x'
      /* || cmd == 'l' */) {
    if (num < NUM) {
      i = num;
      num++;
    }
    else {
      i = nextobj;
      nextobj++;
      if (nextobj >= num) nextobj = 0;

      // destroy the body and geoms for slot i
      dBodyDestroy (obj[i].body);
      for (k=0; k < GPB; k++) {
	if (obj[i].geom[k]) dGeomDestroy (obj[i].geom[k]);
      }
      memset (&obj[i],0,sizeof(obj[i]));
    }

    obj[i].body = dBodyCreate (world);
    for (k=0; k<3; k++) sides[k] = dRandReal()*0.5+0.1;

    dMatrix3 R;
    if (random_pos) {
// ************************************************************************
// Y-Conversion
// ************************************************************************
dBodySetPosition (obj[i].body, 1,10,2);
// ************************************************************************

/*      dBodySetPosition (obj[i].body,
			dRandReal()*2-1,dRandReal()*2-1,dRandReal()+1);
*/      dRFromAxisAndAngle (R,dRandReal()*2.0-1.0,dRandReal()*2.0-1.0,
			  dRandReal()*2.0-1.0,dRandReal()*10.0-5.0);
    }
    else {
      dReal maxheight = 0;
      for (k=0; k<num; k++) {
	const dReal *pos = dBodyGetPosition (obj[k].body);
	if (pos[2] > maxheight) maxheight = pos[2];
      }
      dBodySetPosition (obj[i].body, 0,0,maxheight+1);
      dRFromAxisAndAngle (R,0,0,1,dRandReal()*10.0-5.0);
    }
    dBodySetRotation (obj[i].body,R);
    dBodySetData (obj[i].body,(void*)(size_t)i);

    if (cmd == 'b') {
      dMassSetBox (&m,DENSITY,sides[0],sides[1],sides[2]);
      obj[i].geom[0] = dCreateBox (space,sides[0],sides[1],sides[2]);
    }
    else if (cmd == 'c') {
      sides[0] *= 0.5;
      dMassSetCapsule (&m,DENSITY,3,sides[0],sides[1]);
      obj[i].geom[0] = dCreateCapsule (space,sides[0],sides[1]);
    }
/*
    // cylinder option not yet implemented
    else if (cmd == 'l') {
      sides[1] *= 0.5;
      dMassSetCapsule (&m,DENSITY,3,sides[0],sides[1]);
      obj[i].geom[0] = dCreateCylinder (space,sides[0],sides[1]);
    }
*/
    else if (cmd == 's') {
      sides[0] *= 0.5;
      dMassSetSphere (&m,DENSITY,sides[0]);
      obj[i].geom[0] = dCreateSphere (space,sides[0]);
    }
    else if (cmd == 'x') {
      dGeomID g2[GPB];		// encapsulated geometries
      dReal dpos[GPB][3];	// delta-positions for encapsulated geometries

      // start accumulating masses for the encapsulated geometries
      dMass m2;
      dMassSetZero (&m);

      // set random delta positions
      for (j=0; j<GPB; j++) {
	for (k=0; k<3; k++) dpos[j][k] = dRandReal()*0.3-0.15;
      }

      for (k=0; k<GPB; k++) {
	obj[i].geom[k] = dCreateGeomTransform (space);
	dGeomTransformSetCleanup (obj[i].geom[k],1);
	if (k==0) {
	  dReal radius = dRandReal()*0.25+0.05;
	  g2[k] = dCreateSphere (0,radius);
	  dMassSetSphere (&m2,DENSITY,radius);
	}
	else if (k==1) {
	  g2[k] = dCreateBox (0,sides[0],sides[1],sides[2]);
	  dMassSetBox (&m2,DENSITY,sides[0],sides[1],sides[2]);
	}
	else {
	  dReal radius = dRandReal()*0.1+0.05;
	  dReal length = dRandReal()*1.0+0.1;
	  g2[k] = dCreateCapsule (0,radius,length);
	  dMassSetCapsule (&m2,DENSITY,3,radius,length);
	}
	dGeomTransformSetGeom (obj[i].geom[k],g2[k]);

	// set the transformation (adjust the mass too)
	dGeomSetPosition (g2[k],dpos[k][0],dpos[k][1],dpos[k][2]);
	dMassTranslate (&m2,dpos[k][0],dpos[k][1],dpos[k][2]);
	dMatrix3 Rtx;
	dRFromAxisAndAngle (Rtx,dRandReal()*2.0-1.0,dRandReal()*2.0-1.0,
			    dRandReal()*2.0-1.0,dRandReal()*10.0-5.0);
	dGeomSetRotation (g2[k],Rtx);
	dMassRotate (&m2,Rtx);

	// add to the total mass
	dMassAdd (&m,&m2);
      }

      // move all encapsulated objects so that the center of mass is (0,0,0)
      for (k=0; k<2; k++) {
	dGeomSetPosition (g2[k],
			  dpos[k][0]-m.c[0],
			  dpos[k][1]-m.c[1],
			  dpos[k][2]-m.c[2]);
      }
      dMassTranslate (&m,-m.c[0],-m.c[1],-m.c[2]);
    }

    for (k=0; k < GPB; k++) {
      if (obj[i].geom[k]) dGeomSetBody (obj[i].geom[k],obj[i].body);
    }

    dBodySetMass (obj[i].body,&m);
  }

  if (cmd == ' ') {
    selected++;
    if (selected >= num) selected = 0;
    if (selected < 0) selected = 0;
  }
  else if (cmd == 'd' && selected >= 0 && selected < num) {
    dBodyDisable (obj[selected].body);
  }
  else if (cmd == 'e' && selected >= 0 && selected < num) {
    dBodyEnable (obj[selected].body);
  }
  else if (cmd == 'a') {
    show_aabb ^= 1;
  }
  else if (cmd == 't') {
    show_contacts ^= 1;
  }
  else if (cmd == 'r') {
    random_pos ^= 1;
  }
}


// draw a geom

void drawGeom (dGeomID g, const dReal *pos, const dReal *R, int show_aabb)
{
  if (!g) return;
  if (!pos) pos = dGeomGetPosition (g);
  if (!R) R = dGeomGetRotation (g);

  int type = dGeomGetClass (g);
  if (type == dBoxClass) {
    dVector3 sides;
    dGeomBoxGetLengths (g,sides);
    dsDrawBox (pos,R,sides);
  }
  else if (type == dSphereClass) {
    dsDrawSphere (pos,R,dGeomSphereGetRadius (g));
  }
  else if (type == dCapsuleClass) {
    dReal radius,length;
    dGeomCapsuleGetParams (g,&radius,&length);
    dsDrawCapsule (pos,R,length,radius);
  }
/*
  // cylinder option not yet implemented
  else if (type == dCylinderClass) {
    dReal radius,length;
    dGeomCylinderGetParams (g,&radius,&length);
    dsDrawCylinder (pos,R,length,radius);
  }
*/
  else if (type == dGeomTransformClass) {
    dGeomID g2 = dGeomTransformGetGeom (g);
    const dReal *pos2 = dGeomGetPosition (g2);
    const dReal *R2 = dGeomGetRotation (g2);
    dVector3 actual_pos;
    dMatrix3 actual_R;
    dMultiply0_331 (actual_pos,R,pos2);
    actual_pos[0] += pos[0];
    actual_pos[1] += pos[1];
    actual_pos[2] += pos[2];
    dMultiply0_333 (actual_R,R,R2);
    drawGeom (g2,actual_pos,actual_R,0);
  }

  if (show_aabb) {
    // draw the bounding box for this geom
    dReal aabb[6];
    dGeomGetAABB (g,aabb);
    dVector3 bbpos;
    for (int i=0; i<3; i++) bbpos[i] = 0.5*(aabb[i*2] + aabb[i*2+1]);
    dVector3 bbsides;
    for (int j=0; j<3; j++) bbsides[j] = aabb[j*2+1] - aabb[j*2];
    dMatrix3 RI;
    dRSetIdentity (RI);
    dsSetColorAlpha (1,0,0,0.5);
    dsDrawBox (bbpos,RI,bbsides);
  }
}


// simulation loop

static void simLoop (int pause)
{
for(int i = 0; i < 3000000; i++)
	int dd = 0;

  dsSetColor (0,0,2);
  dSpaceCollide (space,0,&nearCallback);
  if (!pause) dWorldStep (world,0.05);
  //if (!pause) dWorldStepFast (world,0.05, 1);

  // remove all contact joints
  dJointGroupEmpty (contactgroup);

  dsSetColor (1,1,0);
  dsSetTexture (DS_WOOD);
  for (int i=0; i<num; i++) {
    for (int j=0; j < GPB; j++) {
      if (i==selected) {
	dsSetColor (0,0.7,1);
      }
      else if (! dBodyIsEnabled (obj[i].body)) {
	dsSetColor (1,0,0);
      }
      else {
	dsSetColor (1,1,0);
      }
      drawGeom (obj[i].geom[j],0,0,show_aabb);
    }
  }

  /*{
    for (int i = 1; i < IndexCount; i++) {
      dsDrawLine(Vertices[Indices[i - 1]], Vertices[Indices[i]]);
    }
  }*/

  {const dReal* Pos = dGeomGetPosition(TriMesh);
  const dReal* Rot = dGeomGetRotation(TriMesh);

  {for (int i = 0; i < IndexCount / 3; i++){
    const float *p = Vertices[Indices[i * 3 + 0]];
    const dVector3 v0 = { p[0], p[1], p[2] };
    p = Vertices[Indices[i * 3 + 1]];
    const dVector3 v1 = { p[0], p[1], p[2] };
    p = Vertices[Indices[i * 3 + 2]];
    const dVector3 v2 = { p[0], p[1], p[2] };
    dsDrawTriangle(Pos, Rot, v0, v1, v2, 0);
  }}}

  if (Ray){
	  dVector3 Origin, Direction;
	  dGeomRayGet(Ray, Origin, Direction);
	  
	  dReal Length = dGeomRayGetLength(Ray);
	  
	  dVector3 End;
	  End[0] = Origin[0] + (Direction[0] * Length);
	  End[1] = Origin[1] + (Direction[1] * Length);
	  End[2] = Origin[2] + (Direction[2] * Length);
	  End[3] = Origin[3] + (Direction[3] * Length);
	  
	  dsDrawLine(Origin, End);
  }
}


int main (int argc, char **argv)
{
  // setup pointers to drawstuff callback functions
  dsFunctions fn;
  fn.version = DS_VERSION;
  fn.start = &start;
  fn.step = &simLoop;
  fn.command = &command;
  fn.stop = 0;
  fn.path_to_textures = DRAWSTUFF_TEXTURE_PATH;

  // create world
  dInitODE2(0);
  world = dWorldCreate();

  space = dSimpleSpaceCreate(0);
  contactgroup = dJointGroupCreate (0);
// ************************************************************************
// Y-Conversion
// ************************************************************************
  dWorldSetGravity (world,0,-0.5,0);
// ************************************************************************
  dWorldSetCFM (world,1e-5);
  //dCreatePlane (space,0,0,1,0);
  memset (obj,0,sizeof(obj));
  
// ************************************************************************
// Y-Conversion
// ************************************************************************
  Size[0] = 5.0f;
  Size[1] = 5.0f;
  Size[2] = 2.5f;
  
  Vertices[0][0] = -Size[0];
  Vertices[0][1] = Size[2];
  Vertices[0][2] = -Size[1];
  
  Vertices[1][0] = Size[0];
  Vertices[1][1] = Size[2];
  Vertices[1][2] = -Size[1];
  
  Vertices[2][0] = Size[0];
  Vertices[2][1] = Size[2];
  Vertices[2][2] = Size[1];
  
  Vertices[3][0] = -Size[0];
  Vertices[3][1] = Size[2];
  Vertices[3][2] = Size[1];
  
  Vertices[4][0] = 0;
  Vertices[4][1] = 0;
  Vertices[4][2] = 0;
  
  Indices[0] = 0;
  Indices[1] = 1;
  Indices[2] = 4;
  
  Indices[3] = 1;
  Indices[4] = 2;
  Indices[5] = 4;
  
  Indices[6] = 2;
  Indices[7] = 3;
  Indices[8] = 4;
  
  Indices[9] = 3;
  Indices[10] = 0;
  Indices[11] = 4;
// ************************************************************************

  dTriMeshDataID Data = dGeomTriMeshDataCreate();

  //dGeomTriMeshDataBuildSimple(Data, (dReal*)Vertices, VertexCount, Indices, IndexCount);
  dGeomTriMeshDataBuildSingle(Data, Vertices[0], 3 * sizeof(float), VertexCount, &Indices[0], IndexCount, 3 * sizeof(dTriIndex));

  TriMesh = dCreateTriMesh(space, Data, 0, 0, 0);

  //dGeomSetPosition(TriMesh, 0, 0, 1.0);
  
  Ray = dCreateRay(space, 0.9);
  dVector3 Origin, Direction;
  Origin[0] = 0.0;
  Origin[1] = 0;
  Origin[2] = 0.5;
  Origin[3] = 0;
  
  Direction[0] = 0;
  Direction[1] = 1.1f;
  Direction[2] = -1;
  Direction[3] = 0;
  dNormalize3(Direction);
  
  dGeomRaySet(Ray, Origin[0], Origin[1], Origin[2], Direction[0], Direction[1], Direction[2]);
  
  // run simulation
  dsSimulationLoop (argc,argv,352,288,&fn);

  dJointGroupDestroy (contactgroup);
  dSpaceDestroy (space);
  dWorldDestroy (world);
  dCloseODE();
  return 0;
}




/*
// TriMesh test by Erwin de Vries

#include <ode/ode.h>
#include <drawstuff/drawstuff.h>
#include "texturepath.h"

#ifdef _MSC_VER
#pragma warning(disable:4244 4305)  // for VC++, no precision loss complaints
#endif

// select correct drawing functions

#ifdef dDOUBLE
#define dsDrawBox dsDrawBoxD
#define dsDrawSphere dsDrawSphereD
#define dsDrawCylinder dsDrawCylinderD
#define dsDrawCapsule dsDrawCapsuleD
#define dsDrawLine dsDrawLineD
#define dsDrawTriangle dsDrawTriangleD
#endif


// some constants

#define NUM 200			// max number of objects
#define DENSITY (5.0)		// density of all objects
#define GPB 3			// maximum number of geometries per body
#define MAX_CONTACTS 40		// maximum number of contact points per body


// dynamics and collision objects

struct MyObject {
  dBodyID body;			// the body
  dGeomID geom[GPB];		// geometries representing this body
};

static int num=0;		// number of objects in simulation
static int nextobj=0;		// next object to recycle if num==NUM
static dWorldID world;
static dSpaceID space;
static MyObject obj[NUM];
static dJointGroupID contactgroup;
static int selected = -1;	// selected object
static int show_aabb = 0;	// show geom AABBs?
static int show_contacts = 0;	// show contact points?
static int random_pos = 1;	// drop objects from random position?

#define VertexCount 5
#define IndexCount 12

static dVector3 Size;
static float Vertices[VertexCount][3];
static dTriIndex Indices[IndexCount];

static dGeomID TriMesh;
static dGeomID Ray;


// this is called by dSpaceCollide when two objects in space are
// potentially colliding.

static void nearCallback (void *data, dGeomID o1, dGeomID o2)
{
  int i;
  // if (o1->body && o2->body) return;

  // exit without doing anything if the two bodies are connected by a joint
  dBodyID b1 = dGeomGetBody(o1);
  dBodyID b2 = dGeomGetBody(o2);
  if (b1 && b2 && dAreConnectedExcluding (b1,b2,dJointTypeContact)) return;

  dContact contact[MAX_CONTACTS];   // up to MAX_CONTACTS contacts per box-box
  for (i=0; i<MAX_CONTACTS; i++) {
    contact[i].surface.mode = dContactBounce | dContactSoftCFM;
    contact[i].surface.mu = dInfinity;
    contact[i].surface.mu2 = 0;
    contact[i].surface.bounce = 0.1;
    contact[i].surface.bounce_vel = 0.1;
    contact[i].surface.soft_cfm = 0.01;
  }
  if (int numc = dCollide (o1,o2,MAX_CONTACTS,&contact[0].geom,
			   sizeof(dContact))) {
    dMatrix3 RI;
    dRSetIdentity (RI);
    const dReal ss[3] = {0.02,0.02,0.02};
    for (i=0; i<numc; i++) {
		if (dGeomGetClass(o1) == dRayClass || dGeomGetClass(o2) == dRayClass){
			dMatrix3 Rotation;
			dRSetIdentity(Rotation);
			dsDrawSphere(contact[i].geom.pos, Rotation, REAL(0.01));
			
			dVector3 End;
			End[0] = contact[i].geom.pos[0] + (contact[i].geom.normal[0] * contact[i].geom.depth);
			End[1] = contact[i].geom.pos[1] + (contact[i].geom.normal[1] * contact[i].geom.depth);
			End[2] = contact[i].geom.pos[2] + (contact[i].geom.normal[2] * contact[i].geom.depth);
			End[3] = contact[i].geom.pos[3] + (contact[i].geom.normal[3] * contact[i].geom.depth);
			
			dsDrawLine(contact[i].geom.pos, End);
			continue;
		}
		
      dJointID c = dJointCreateContact (world,contactgroup,contact+i);
      dJointAttach (c,b1,b2);
      if (show_contacts) dsDrawBox (contact[i].geom.pos,RI,ss);
    }
  }
}


// start simulation - set viewpoint

static void start()
{
  dAllocateODEDataForThread(dAllocateMaskAll);

  static float xyz[3] = {2.1640f,-1.3079f,1.7600f};
  static float hpr[3] = {125.5000f,-17.0000f,0.0000f};
  dsSetViewpoint (xyz,hpr);
  printf ("To drop another object, press:\n");
  printf ("   b for box.\n");
  printf ("   s for sphere.\n");
  printf ("   c for cylinder.\n");
  printf ("   x for a composite object.\n");
  printf ("To select an object, press space.\n");
  printf ("To disable the selected object, press d.\n");
  printf ("To enable the selected object, press e.\n");
  printf ("To toggle showing the geom AABBs, press a.\n");
  printf ("To toggle showing the contact points, press t.\n");
  printf ("To toggle dropping from random position/orientation, press r.\n");
}


char locase (char c)
{
  if (c >= 'A' && c <= 'Z') return c - ('a'-'A');
  else return c;
}


// called when a key pressed

static void command (int cmd)
{
  int i,j,k;
  dReal sides[3];
  dMass m;

  cmd = locase (cmd);
  if (cmd == 'b' || cmd == 's' || cmd == 'c' || cmd == 'x'
    if (num < NUM) {
      i = num;
      num++;
    }
    else {
      i = nextobj;
      nextobj++;
      if (nextobj >= num) nextobj = 0;

      // destroy the body and geoms for slot i
      dBodyDestroy (obj[i].body);
      for (k=0; k < GPB; k++) {
	if (obj[i].geom[k]) dGeomDestroy (obj[i].geom[k]);
      }
      memset (&obj[i],0,sizeof(obj[i]));
    }

    obj[i].body = dBodyCreate (world);
    for (k=0; k<3; k++) sides[k] = dRandReal()*0.5+0.1;

    dMatrix3 R;
    if (random_pos) {
      dBodySetPosition (obj[i].body,
			dRandReal()*2-1,dRandReal()*2-1,dRandReal()+1);
      dRFromAxisAndAngle (R,dRandReal()*2.0-1.0,dRandReal()*2.0-1.0,
			  dRandReal()*2.0-1.0,dRandReal()*10.0-5.0);
    }
    else {
      dReal maxheight = 0;
      for (k=0; k<num; k++) {
	const dReal *pos = dBodyGetPosition (obj[k].body);
	if (pos[2] > maxheight) maxheight = pos[2];
      }
      dBodySetPosition (obj[i].body, 0,0,maxheight+1);
      dRFromAxisAndAngle (R,0,0,1,dRandReal()*10.0-5.0);
    }
    dBodySetRotation (obj[i].body,R);
    dBodySetData (obj[i].body,(void*)(size_t)i);

    if (cmd == 'b') {
      dMassSetBox (&m,DENSITY,sides[0],sides[1],sides[2]);
      obj[i].geom[0] = dCreateBox (space,sides[0],sides[1],sides[2]);
    }
    else if (cmd == 'c') {
      sides[0] *= 0.5;
      dMassSetCapsule (&m,DENSITY,3,sides[0],sides[1]);
      obj[i].geom[0] = dCreateCapsule (space,sides[0],sides[1]);
    }

	else if (cmd == 's') {
      sides[0] *= 0.5;
      dMassSetSphere (&m,DENSITY,sides[0]);
      obj[i].geom[0] = dCreateSphere (space,sides[0]);
    }
    else if (cmd == 'x') {
      dGeomID g2[GPB];		// encapsulated geometries
      dReal dpos[GPB][3];	// delta-positions for encapsulated geometries

      // start accumulating masses for the encapsulated geometries
      dMass m2;
      dMassSetZero (&m);

      // set random delta positions
      for (j=0; j<GPB; j++) {
	for (k=0; k<3; k++) dpos[j][k] = dRandReal()*0.3-0.15;
      }

      for (k=0; k<GPB; k++) {
	obj[i].geom[k] = dCreateGeomTransform (space);
	dGeomTransformSetCleanup (obj[i].geom[k],1);
	if (k==0) {
	  dReal radius = dRandReal()*0.25+0.05;
	  g2[k] = dCreateSphere (0,radius);
	  dMassSetSphere (&m2,DENSITY,radius);
	}
	else if (k==1) {
	  g2[k] = dCreateBox (0,sides[0],sides[1],sides[2]);
	  dMassSetBox (&m2,DENSITY,sides[0],sides[1],sides[2]);
	}
	else {
	  dReal radius = dRandReal()*0.1+0.05;
	  dReal length = dRandReal()*1.0+0.1;
	  g2[k] = dCreateCapsule (0,radius,length);
	  dMassSetCapsule (&m2,DENSITY,3,radius,length);
	}
	dGeomTransformSetGeom (obj[i].geom[k],g2[k]);

	// set the transformation (adjust the mass too)
	dGeomSetPosition (g2[k],dpos[k][0],dpos[k][1],dpos[k][2]);
	dMassTranslate (&m2,dpos[k][0],dpos[k][1],dpos[k][2]);
	dMatrix3 Rtx;
	dRFromAxisAndAngle (Rtx,dRandReal()*2.0-1.0,dRandReal()*2.0-1.0,
			    dRandReal()*2.0-1.0,dRandReal()*10.0-5.0);
	dGeomSetRotation (g2[k],Rtx);
	dMassRotate (&m2,Rtx);

	// add to the total mass
	dMassAdd (&m,&m2);
      }

      // move all encapsulated objects so that the center of mass is (0,0,0)
      for (k=0; k<2; k++) {
	dGeomSetPosition (g2[k],
			  dpos[k][0]-m.c[0],
			  dpos[k][1]-m.c[1],
			  dpos[k][2]-m.c[2]);
      }
      dMassTranslate (&m,-m.c[0],-m.c[1],-m.c[2]);
    }

    for (k=0; k < GPB; k++) {
      if (obj[i].geom[k]) dGeomSetBody (obj[i].geom[k],obj[i].body);
    }

    dBodySetMass (obj[i].body,&m);
  }

  if (cmd == ' ') {
    selected++;
    if (selected >= num) selected = 0;
    if (selected < 0) selected = 0;
  }
  else if (cmd == 'd' && selected >= 0 && selected < num) {
    dBodyDisable (obj[selected].body);
  }
  else if (cmd == 'e' && selected >= 0 && selected < num) {
    dBodyEnable (obj[selected].body);
  }
  else if (cmd == 'a') {
    show_aabb ^= 1;
  }
  else if (cmd == 't') {
    show_contacts ^= 1;
  }
  else if (cmd == 'r') {
    random_pos ^= 1;
  }
}


// draw a geom

void drawGeom (dGeomID g, const dReal *pos, const dReal *R, int show_aabb)
{
  if (!g) return;
  if (!pos) pos = dGeomGetPosition (g);
  if (!R) R = dGeomGetRotation (g);

  int type = dGeomGetClass (g);
  if (type == dBoxClass) {
    dVector3 sides;
    dGeomBoxGetLengths (g,sides);
    dsDrawBox (pos,R,sides);
  }
  else if (type == dSphereClass) {
    dsDrawSphere (pos,R,dGeomSphereGetRadius (g));
  }
  else if (type == dCapsuleClass) {
    dReal radius,length;
    dGeomCapsuleGetParams (g,&radius,&length);
    dsDrawCapsule (pos,R,length,radius);
  }

  else if (type == dGeomTransformClass) {
    dGeomID g2 = dGeomTransformGetGeom (g);
    const dReal *pos2 = dGeomGetPosition (g2);
    const dReal *R2 = dGeomGetRotation (g2);
    dVector3 actual_pos;
    dMatrix3 actual_R;
    dMultiply0_331 (actual_pos,R,pos2);
    actual_pos[0] += pos[0];
    actual_pos[1] += pos[1];
    actual_pos[2] += pos[2];
    dMultiply0_333 (actual_R,R,R2);
    drawGeom (g2,actual_pos,actual_R,0);
  }

  if (show_aabb) {
    // draw the bounding box for this geom
    dReal aabb[6];
    dGeomGetAABB (g,aabb);
    dVector3 bbpos;
    for (int i=0; i<3; i++) bbpos[i] = 0.5*(aabb[i*2] + aabb[i*2+1]);
    dVector3 bbsides;
    for (int j=0; j<3; j++) bbsides[j] = aabb[j*2+1] - aabb[j*2];
    dMatrix3 RI;
    dRSetIdentity (RI);
    dsSetColorAlpha (1,0,0,0.5);
    dsDrawBox (bbpos,RI,bbsides);
  }
}


// simulation loop

static void simLoop (int pause)
{
for(int i = 0; i < 3000000; i++)
	int dd = 0;

  dsSetColor (0,0,2);
  dSpaceCollide (space,0,&nearCallback);
  if (!pause) dWorldStep (world,0.05);
  //if (!pause) dWorldStepFast (world,0.05, 1);

  // remove all contact joints
  dJointGroupEmpty (contactgroup);

  dsSetColor (1,1,0);
  dsSetTexture (DS_WOOD);
  for (int i=0; i<num; i++) {
    for (int j=0; j < GPB; j++) {
      if (i==selected) {
	dsSetColor (0,0.7,1);
      }
      else if (! dBodyIsEnabled (obj[i].body)) {
	dsSetColor (1,0,0);
      }
      else {
	dsSetColor (1,1,0);
      }
      drawGeom (obj[i].geom[j],0,0,show_aabb);
    }
  }

  {const dReal* Pos = dGeomGetPosition(TriMesh);
  const dReal* Rot = dGeomGetRotation(TriMesh);

  {for (int i = 0; i < IndexCount / 3; i++){
    const float *p = Vertices[Indices[i * 3 + 0]];
    const dVector3 v0 = { p[0], p[1], p[2] };
    p = Vertices[Indices[i * 3 + 1]];
    const dVector3 v1 = { p[0], p[1], p[2] };
    p = Vertices[Indices[i * 3 + 2]];
    const dVector3 v2 = { p[0], p[1], p[2] };
    dsDrawTriangle(Pos, Rot, v0, v1, v2, 0);
  }}}

  if (Ray){
	  dVector3 Origin, Direction;
	  dGeomRayGet(Ray, Origin, Direction);
	  
	  dReal Length = dGeomRayGetLength(Ray);
	  
	  dVector3 End;
	  End[0] = Origin[0] + (Direction[0] * Length);
	  End[1] = Origin[1] + (Direction[1] * Length);
	  End[2] = Origin[2] + (Direction[2] * Length);
	  End[3] = Origin[3] + (Direction[3] * Length);
	  
	  dsDrawLine(Origin, End);
  }
}


int main (int argc, char **argv)
{
  // setup pointers to drawstuff callback functions
  dsFunctions fn;
  fn.version = DS_VERSION;
  fn.start = &start;
  fn.step = &simLoop;
  fn.command = &command;
  fn.stop = 0;
  fn.path_to_textures = DRAWSTUFF_TEXTURE_PATH;

  // create world
  dInitODE2(0);
  world = dWorldCreate();

  space = dSimpleSpaceCreate(0);
  contactgroup = dJointGroupCreate (0);
  dWorldSetGravity (world,0,0,-0.5);
  dWorldSetCFM (world,1e-5);
  //dCreatePlane (space,0,0,1,0);
  memset (obj,0,sizeof(obj));
  
  Size[0] = 5.0f;
  Size[1] = 5.0f;
  Size[2] = 2.5f;
  
  Vertices[0][0] = -Size[0];
  Vertices[0][1] = -Size[1];
  Vertices[0][2] = Size[2];
  
  Vertices[1][0] = Size[0];
  Vertices[1][1] = -Size[1];
  Vertices[1][2] = Size[2];
  
  Vertices[2][0] = Size[0];
  Vertices[2][1] = Size[1];
  Vertices[2][2] = Size[2];
  
  Vertices[3][0] = -Size[0];
  Vertices[3][1] = Size[1];
  Vertices[3][2] = Size[2];
  
  Vertices[4][0] = 0;
  Vertices[4][1] = 0;
  Vertices[4][2] = 0;
  
  Indices[0] = 0;
  Indices[1] = 1;
  Indices[2] = 4;
  
  Indices[3] = 1;
  Indices[4] = 2;
  Indices[5] = 4;
  
  Indices[6] = 2;
  Indices[7] = 3;
  Indices[8] = 4;
  
  Indices[9] = 3;
  Indices[10] = 0;
  Indices[11] = 4;

  dTriMeshDataID Data = dGeomTriMeshDataCreate();

  //dGeomTriMeshDataBuildSimple(Data, (dReal*)Vertices, VertexCount, Indices, IndexCount);
  dGeomTriMeshDataBuildSingle(Data, Vertices[0], 3 * sizeof(float), VertexCount, &Indices[0], IndexCount, 3 * sizeof(dTriIndex));

  TriMesh = dCreateTriMesh(space, Data, 0, 0, 0);

  //dGeomSetPosition(TriMesh, 0, 0, 1.0);
  
  Ray = dCreateRay(space, 0.9);
  dVector3 Origin, Direction;
  Origin[0] = 0.0;
  Origin[1] = 0;
  Origin[2] = 0.5;
  Origin[3] = 0;
  
  Direction[0] = 0;
  Direction[1] = 1.1f;
  Direction[2] = -1;
  Direction[3] = 0;
  dNormalize3(Direction);
  
  dGeomRaySet(Ray, Origin[0], Origin[1], Origin[2], Direction[0], Direction[1], Direction[2]);
  
  // run simulation
  dsSimulationLoop (argc,argv,352,288,&fn);

  dJointGroupDestroy (contactgroup);
  dSpaceDestroy (space);
  dWorldDestroy (world);
  dCloseODE();
  return 0;
}
*/

 

As I understand it, Alpha Testing will simply ignore those pixels, that do not pass the test.

I have made an alpha-test with  renderstates [D3DRS_ALPHAFUNC, D3DCMP_GREATER] and [D3DRS_ALPHAREF, 128].

 

Since the problem arose, I have simplified my texture, making the rgb-layer completely white, while preserving the alpha-layer.

 

I have further simplified my shader, so that it now simply outputs the texture raw, and that is all. No lighting or any other kinds of calculations.

 

The result is still scorched edges, as can be seen below:

 

 

I would have expected a completely white plant, with no grey-scales (partial alpha) and no black edges.

How come, that the alpha is burned into the texture like that?

 

As can be seen, the pixel shader is extremely simple (I removed the argument list because it is irrelevant (except a_texcoord0)).

float4 PS_light_SHADOW(...) : COLOR
{
    return tex2D(g_texturemap_sampler, a_texcoord0);
}

My renderstates are as follows:

SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE)
SetRenderState(D3DRS_ZWRITEENABLE, TRUE)
SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE)
SetRenderState(D3DRS_ALPHATESTENABLE, TRUE)
SetRenderState(D3DRS_ALPHAFUNC, D3DCMP_GREATER)
SetRenderState(D3DRS_ALPHAREF, 128)

 

Thank you in advance.

I wish to transfer an instancing vertex, that beyond the matrix has four very small integers, two of which are indexes into a texturemap shared by several different other objects - a texturemap holding many different kinds of grass and flowers. I call each of them "frames" and the texture a "framemap"l The last two define the dimensions (x/y) of the frame map, that the indexes point into.

From the max dimensions and the indexes, the shader will be able to calculate the offset into the frame map. I found, that this should be cheaper to transfer than simply the float offsets, if I used special types.

 

The integers are so small, that I can get away with only 4 bits for each, as I allow the frame map to have maximum 16x16 frames. Combined the indexes- and dimensions-variables will occupy 4x4=16 bits.

 

However, I cannot find a data type for transferring (http://msdn.microsoft.com/en-us/library/windows/desktop/bb172533%28v=vs.85%29.aspx), which takes only 4 bits. Actually nothing that takes less than 32 bits. Is that really so?

I could live with packing variables together and unpacking on the other end, but if I am stuck with a minimum unit of 32 bits, then Im not sure it is worth the price.

 

Is there a solution to this? Is there any way I can transfer variables of less than 32 bits?

I am currently working on instancing and I have a problem with sorting the rendering.

If I choose to render only the visible instances, I have to open the instancing render buffer and upload the instancing data for the visible instances. The problem is just, that for each shadowmap this has to be done again, then for reflections, etc. A hell of a lot of locking the render buffer, uploading data and then rendering - every single frame.

I thought about it, and wondered if it is even worth it. Can I not just throw everything at the card? What kind of tradeoffs would each strategy entail?
I recon, that it also depends on the number of instances that are not visible, but what amounts are we talking about before it is no longer feasible to not optimize?

I have an object oriented system, that the rendering works in, and if I have to sort, then we are also talking a number of virtual calls before the hardware-specific call (DirectX 9 in my case) is reached, as the platform-specificness has been abstracted away. These calls (calls to 3 virtual-hierarchies for each setting of renderbuffer, not too much) may also be a factor in evaluating the feasibility, though Im unsure if the factor is so small, that it can be ignored - it is every single frame, after all.

I have been working on roads based on splines, when I encountered a problem, where the normalmap messed up the result, based on the orientation of the road.

When I run a straight road from south to north, it looks quite normal, but when I run the same road from north to south, the road looks as if it has alot of specular value on its material, although that is not the case.
All variables are the same otherwise, like the sun (there is only one lightsource in the scene, the directional light of the sun).

It looks like this:




Normally when you put an object in the scene, it will come with a world matrix, through which the light direction will be transformed. That does not happen with my road, and my guess is, that that is the problem. With a winding road, there can be no single matrix for the entire road anyway. So my guess is, that this has to be solved through the calculated tangents, but I don't know if that is true, or how to do it.

Thanks in advance.