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PhysX4.1/physx/snippets/snippetsplitsim/SnippetSplitSim.cpp
2025-11-28 23:13:44 +05:30

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//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of NVIDIA CORPORATION nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright (c) 2008-2021 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
// *******************************************************************************************************
// In addition to the simulate() function, which performs both collision detection and dynamics update,
// the PhysX SDK provides an api for separate execution of the collision detection and dynamics update steps.
// We shall refer to this feature as "split sim". This snippet demonstrates two ways to use the split sim feature
// so that application work can be performed concurrently with the collision detection step.
// The snippet creates a list of kinematic box actors along with a number of dynamic actors that
// interact with the kinematic actors.
//The defines OVERLAP_COLLISION_AND_RENDER_WITH_NO_LAG and OVERLAP_COLLISION_AND_RENDER_WITH_ONE_FRAME_LAG
//demonstrate two distinct modes of split sim operation:
// (1)Enabling OVERLAP_COLLISION_AND_RENDER_WITH_NO_LAG allows the collision detection step to run in parallel
// with the renderer and with the update of the kinematic target poses without introducing any lag between
// application time and physics time. This is equivalent to calling simulate() and fetchResults() with the key
// difference being that the application can schedule work to run concurrently with the collision detection.
// A consequence of this approach is that the first frame is more expensive than subsequent frames because it has to
// perform blocking collision detection and dynamics update calls.
// (2)OVERLAP_COLLISION_AND_RENDER_WITH_ONE_FRAME_LAG also allows the collision to run in parallel with
// the renderer and the update of the kinematic target poses but this time with a lag between physics time and
// application time; that is, the physics is always a single timestep behind the application because the first
// frame merely starts the collision detection for the subsequent frame. A consequence of this approach is that
// the first frame is cheaper than subsequent frames.
// ********************************************************************************************************
#include <ctype.h>
#include "PxPhysicsAPI.h"
#include "../snippetcommon/SnippetPrint.h"
#include "../snippetcommon/SnippetPVD.h"
#include "../snippetutils/SnippetUtils.h"
//This will allow the split sim to overlap collision and render and game logic.
#define OVERLAP_COLLISION_AND_RENDER_WITH_NO_LAG 1
#define OVERLAP_COLLISION_AND_RENDER_WITH_ONE_FRAME_LAG 0
using namespace physx;
PxDefaultAllocator gAllocator;
PxDefaultErrorCallback gErrorCallback;
PxFoundation* gFoundation = NULL;
PxPhysics* gPhysics = NULL;
PxDefaultCpuDispatcher* gDispatcher = NULL;
PxScene* gScene = NULL;
PxMaterial* gMaterial = NULL;
PxPvd* gPvd = NULL;
#define NB_KINE_X 16
#define NB_KINE_Y 16
#define KINE_SCALE 3.1f
static bool isFirstFrame = true;
PxRigidDynamic* gKinematics[NB_KINE_Y][NB_KINE_X];
PxQuat setRotY(PxMat33& m, const PxReal angle)
{
m = PxMat33(PxIdentity);
const PxReal cos = cosf(angle);
const PxReal sin = sinf(angle);
m[0][0] = m[2][2] = cos;
m[0][2] = -sin;
m[2][0] = sin;
return PxQuat(m);
}
void createDynamics()
{
const PxU32 NbX = 8;
const PxU32 NbY = 8;
const PxVec3 dims(0.2f, 0.1f, 0.2f);
const PxReal sphereRadius = 0.2f;
const PxReal capsuleRadius = 0.2f;
const PxReal halfHeight = 0.5f;
const PxU32 NbLayers = 3;
const float YScale = 0.4f;
const float YStart = 6.0f;
PxShape* boxShape = gPhysics->createShape(PxBoxGeometry(dims), *gMaterial);
PxShape* sphereShape = gPhysics->createShape(PxSphereGeometry(sphereRadius), *gMaterial);
PxShape* capsuleShape = gPhysics->createShape(PxCapsuleGeometry(capsuleRadius, halfHeight), *gMaterial);
PX_UNUSED(boxShape);
PX_UNUSED(sphereShape);
PX_UNUSED(capsuleShape);
PxMat33 m;
for(PxU32 j=0;j<NbLayers;j++)
{
const float angle = float(j)*0.08f;
const PxQuat rot = setRotY(m, angle);
const float ScaleX = 4.0f;
const float ScaleY = 4.0f;
for(PxU32 y=0;y<NbY;y++)
{
for(PxU32 x=0;x<NbX;x++)
{
const float xf = (float(x)-float(NbX)*0.5f)*ScaleX;
const float yf = (float(y)-float(NbY)*0.5f)*ScaleY;
PxRigidDynamic* dynamic = NULL;
PxU32 v = j&3;
PxVec3 pos = PxVec3(xf, YStart + float(j)*YScale, yf);
switch(v)
{
case 0:
{
PxTransform pose(pos, rot);
dynamic = gPhysics->createRigidDynamic(pose);
dynamic->attachShape(*boxShape);
break;
}
case 1:
{
PxTransform pose(pos, PxQuat(PxIdentity));
dynamic = gPhysics->createRigidDynamic(pose);
dynamic->attachShape(*sphereShape);
break;
}
default:
{
PxTransform pose(pos, rot);
dynamic = gPhysics->createRigidDynamic(pose);
dynamic->attachShape(*capsuleShape);
break;
}
};
PxRigidBodyExt::updateMassAndInertia(*dynamic, 10.f);
gScene->addActor(*dynamic);
}
}
}
}
void createGroudPlane()
{
PxTransform pose = PxTransform(PxVec3(0.0f, 0.0f, 0.0f),PxQuat(PxHalfPi, PxVec3(0.0f, 0.0f, 1.0f)));
PxRigidStatic* actor = gPhysics->createRigidStatic(pose);
PxShape* shape = PxRigidActorExt::createExclusiveShape(*actor, PxPlaneGeometry(), *gMaterial);
PX_UNUSED(shape);
gScene->addActor(*actor);
}
void createKinematics()
{
const PxU32 NbX = NB_KINE_X;
const PxU32 NbY = NB_KINE_Y;
const PxVec3 dims(1.5f, 0.2f, 1.5f);
const PxQuat rot = PxQuat(PxIdentity);
const float YScale = 0.4f;
PxShape* shape = gPhysics->createShape(PxBoxGeometry(dims), *gMaterial);
const float ScaleX = KINE_SCALE;
const float ScaleY = KINE_SCALE;
for(PxU32 y=0;y<NbY;y++)
{
for(PxU32 x=0;x<NbX;x++)
{
const float xf = (float(x)-float(NbX)*0.5f)*ScaleX;
const float yf = (float(y)-float(NbY)*0.5f)*ScaleY;
PxTransform pose(PxVec3(xf, 0.2f + YScale, yf), rot);
PxRigidDynamic* body = gPhysics->createRigidDynamic(pose);
body->attachShape(*shape);
gScene->addActor(*body);
body->setRigidBodyFlag(PxRigidBodyFlag::eKINEMATIC, true);
gKinematics[y][x] = body;
}
}
}
void updateKinematics(PxReal timeStep)
{
const float YScale = 0.4f;
PxTransform motion;
motion.q = PxQuat(PxIdentity);
static float gTime = 0.0f;
gTime += timeStep;
const PxU32 NbX = NB_KINE_X;
const PxU32 NbY = NB_KINE_Y;
const float Coeff = 0.2f;
const float ScaleX = KINE_SCALE;
const float ScaleY = KINE_SCALE;
for(PxU32 y=0;y<NbY;y++)
{
for(PxU32 x=0;x<NbX;x++)
{
const float xf = (float(x)-float(NbX)*0.5f)*ScaleX;
const float yf = (float(y)-float(NbY)*0.5f)*ScaleY;
const float h = sinf(gTime*2.0f + float(x)*Coeff + + float(y)*Coeff)*2.0f;
motion.p = PxVec3(xf, h + 2.0f + YScale, yf);
PxRigidDynamic* kine = gKinematics[y][x];
kine->setKinematicTarget(motion);
}
}
}
void initPhysics(bool /*interactive*/)
{
gFoundation = PxCreateFoundation(PX_PHYSICS_VERSION, gAllocator, gErrorCallback);
gPvd = PxCreatePvd(*gFoundation);
PxPvdTransport* transport = PxDefaultPvdSocketTransportCreate(PVD_HOST, 5425, 10);
gPvd->connect(*transport,PxPvdInstrumentationFlag::eALL);
gPhysics = PxCreatePhysics(PX_PHYSICS_VERSION, *gFoundation, PxTolerancesScale(),true,gPvd);
PxSceneDesc sceneDesc(gPhysics->getTolerancesScale());
sceneDesc.gravity = PxVec3(0.0f, -9.81f, 0.0f);
gDispatcher = PxDefaultCpuDispatcherCreate(2);
sceneDesc.cpuDispatcher = gDispatcher;
sceneDesc.filterShader = PxDefaultSimulationFilterShader;
gScene = gPhysics->createScene(sceneDesc);
PxPvdSceneClient* pvdClient = gScene->getScenePvdClient();
if(pvdClient)
{
pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_CONSTRAINTS, true);
pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_CONTACTS, true);
pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_SCENEQUERIES, true);
}
gMaterial = gPhysics->createMaterial(0.5f, 0.5f, 0.6f);
PxRigidStatic* groundPlane = PxCreatePlane(*gPhysics, PxPlane(0,1,0,0), *gMaterial);
gScene->addActor(*groundPlane);
createKinematics();
createDynamics();
}
#if OVERLAP_COLLISION_AND_RENDER_WITH_NO_LAG
void stepPhysics(bool /*interactive*/)
{
const PxReal timeStep = 1.0f/60.0f;
if(isFirstFrame)
{
//Run the first frame's collision detection
gScene->collide(timeStep);
isFirstFrame = false;
}
//update the kinematice target pose in parallel with collision running
updateKinematics(timeStep);
gScene->fetchCollision(true);
gScene->advance();
gScene->fetchResults(true);
//Run the deferred collision detection for the next frame. This will run in parallel with render.
gScene->collide(timeStep);
}
#elif OVERLAP_COLLISION_AND_RENDER_WITH_ONE_FRAME_LAG
void stepPhysics(bool /*interactive*/)
{
PxReal timeStep = 1.0/60.0f;
//update the kinematice target pose in parallel with collision running
updateKinematics(timeStep);
if(!isFirstFrame)
{
gScene->fetchCollision(true);
gScene->advance();
gScene->fetchResults(true);
}
isFirstFrame = false;
//Run the deferred collision detection for the next frame. This will run in parallel with render.
gScene->collide(timeStep);
}
#else
void stepPhysics(bool /*interactive*/)
{
PxReal timeStep = 1.0/60.0f;
//update the kinematice target pose in parallel with collision running
gScene->collide(timeStep);
updateKinematics(timeStep);
gScene->fetchCollision(true);
gScene->advance();
gScene->fetchResults(true);
}
#endif
void cleanupPhysics(bool /*interactive*/)
{
#if OVERLAP_COLLISION_AND_RENDER_WITH_NO_LAG || OVERLAP_COLLISION_AND_RENDER_WITH_ONE_FRAME_LAG
//Close out remainder of previously running scene. If we don't do this, it will be implicitly done
//in gScene->release() but a warning will be issued.
gScene->fetchCollision(true);
gScene->advance();
gScene->fetchResults(true);
#endif
PX_RELEASE(gScene);
PX_RELEASE(gDispatcher);
PX_RELEASE(gPhysics);
if(gPvd)
{
PxPvdTransport* transport = gPvd->getTransport();
gPvd->release(); gPvd = NULL;
PX_RELEASE(transport);
}
PX_RELEASE(gFoundation);
printf("SnippetSplitSim done.\n");
}
void keyPress(unsigned char key, const PxTransform& camer)
{
PX_UNUSED(key);
PX_UNUSED(camer);
}
int snippetMain(int, const char*const*)
{
#ifdef RENDER_SNIPPET
extern void renderLoop();
renderLoop();
#else
static const PxU32 frameCount = 100;
initPhysics(false);
for(PxU32 i=0; i<frameCount; i++)
stepPhysics(false);
cleanupPhysics(false);
#endif
return 0;
}