C++ vector3d::Length方法代码示例

void SpaceStation::Render(const vector3d &viewCoords, const matrix4x4d &viewTransform)
{
	LmrObjParams &params = GetLmrObjParams();
	params.label = GetLabel().c_str();
	SetLmrTimeParams();

	for (int i=0; i<MAX_DOCKING_PORTS; i++) {
		params.animStages[ANIM_DOCKING_BAY_1 + i] = m_shipDocking[i].stage;
		params.animValues[ANIM_DOCKING_BAY_1 + i] = m_shipDocking[i].stagePos;
	}

	RenderLmrModel(viewCoords, viewTransform);
	
	/* don't render city if too far away */
	if (viewCoords.Length() > 1000000.0) return;

	// find planet Body*
	Planet *planet;
	{
		Body *_planet = GetFrame()->m_astroBody;
		if ((!_planet) || !_planet->IsType(Object::PLANET)) {
			// orbital spaceport -- don't make city turds
		} else {
			planet = static_cast<Planet*>(_planet);
		
			if (!m_adjacentCity) {
				m_adjacentCity = new CityOnPlanet(planet, this, m_sbody->seed);
			}
			m_adjacentCity->Render(this, viewCoords, viewTransform);
		}
	}
}

// Renders space station and adjacent city if applicable
// For orbital starports: renders as normal
// For surface starports:
//	Lighting: Calculates available light for model and splits light between directly and ambiently lit
//            Lighting is done by manipulating global lights or setting uniforms in atmospheric models shader
void SpaceStation::Render(Graphics::Renderer *r, const Camera *camera, const vector3d &viewCoords, const matrix4x4d &viewTransform)
{
	Body *b = GetFrame()->GetBody();
	assert(b);

	if (!b->IsType(Object::PLANET)) {
		// orbital spaceport -- don't make city turds or change lighting based on atmosphere
		RenderModel(r, camera, viewCoords, viewTransform);
	}

	else {
		std::vector<Graphics::Light> oldLights;
		Color oldAmbient;
		SetLighting(r, camera, oldLights, oldAmbient);

		Planet *planet = static_cast<Planet*>(b);
		/* don't render city if too far away */
		if (viewCoords.Length() < 1000000.0){
			if (!m_adjacentCity) {
				m_adjacentCity = new CityOnPlanet(planet, this, m_sbody->seed);
			}
			m_adjacentCity->Render(r, camera, this, viewCoords, viewTransform);
		}

		RenderModel(r, camera, viewCoords, viewTransform, false);

		ResetLighting(r, oldLights, oldAmbient);
	}
}

// returns direction in ship's frame from this ship to target lead position
vector3d Ship::AIGetLeadDir(const Body *target, const vector3d& targaccel, int gunindex)
{
	assert(target);
	if (ScopedTable(m_equipSet).CallMethod<int>("OccupiedSpace", "laser_front") == 0)
		return target->GetPositionRelTo(this).Normalized();

	const vector3d targpos = target->GetPositionRelTo(this);
	const vector3d targvel = target->GetVelocityRelTo(this);
	// todo: should adjust targpos for gunmount offset

	double projspeed = 0;
	Properties().Get(gunindex?"laser_rear_speed":"laser_front_speed", projspeed);

	vector3d leadpos;
	// avoid a divide-by-zero floating point exception (very nearly zero is ok)
	if( !is_zero_exact(projspeed) ) {
		// first attempt
		double projtime = targpos.Length() / projspeed;
		leadpos = targpos + targvel*projtime + 0.5*targaccel*projtime*projtime;

		// second pass
		projtime = leadpos.Length() / projspeed;
		leadpos = targpos + targvel*projtime + 0.5*targaccel*projtime*projtime;
	} else {
		// default
		leadpos = targpos;
	}

	return leadpos.Normalized();
}

	void UpdateVBOs() {
		PROFILE_SCOPED()
		//create buffer and upload data
		Graphics::VertexBufferDesc vbd;
		vbd.attrib[0].semantic = Graphics::ATTRIB_POSITION;
		vbd.attrib[0].format   = Graphics::ATTRIB_FORMAT_FLOAT3;
		vbd.attrib[1].semantic = Graphics::ATTRIB_NORMAL;
		vbd.attrib[1].format   = Graphics::ATTRIB_FORMAT_FLOAT3;
		vbd.numVertices = ctx->NUMVERTICES();
		vbd.usage = Graphics::BUFFER_USAGE_STATIC;
		m_vertexBuffer.reset(Pi::renderer->CreateVertexBuffer(vbd));

		GasPatchContext::VBOVertex* vtxPtr = m_vertexBuffer->Map<GasPatchContext::VBOVertex>(Graphics::BUFFER_MAP_WRITE);
		assert(m_vertexBuffer->GetDesc().stride == sizeof(GasPatchContext::VBOVertex));
		
		const Sint32 edgeLen = ctx->edgeLen;
		const double frac = ctx->frac;
		for (Sint32 y=0; y<edgeLen; y++) {
			for (Sint32 x=0; x<edgeLen; x++) {
				const vector3d p = GetSpherePoint(x*frac, y*frac);
				const vector3d pSubCentroid = p - clipCentroid;
				clipRadius = std::max(clipRadius, p.Length());
				vtxPtr->pos = vector3f(pSubCentroid);
				vtxPtr->norm = vector3f(p);

				++vtxPtr; // next vertex
			}
		}
		m_vertexBuffer->Unmap();
	}

// returns direction in ship's frame from this ship to target lead position
vector3d Ship::AIGetLeadDir(const Body *target, const vector3d& targaccel, int gunindex)
{
	assert(target);
	if (m_equipment.Get(Equip::SLOT_LASER) == Equip::NONE)
		return target->GetPositionRelTo(this).Normalized();

	const vector3d targpos = target->GetPositionRelTo(this);
	const vector3d targvel = target->GetVelocityRelTo(this);
	// todo: should adjust targpos for gunmount offset

	const int laser = Equip::types[m_equipment.Get(Equip::SLOT_LASER, gunindex)].tableIndex;
	const double projspeed = Equip::lasers[laser].speed;

	vector3d leadpos;
	// avoid a divide-by-zero floating point exception (very nearly zero is ok)
	if( !is_zero_exact(projspeed) ) {
		// first attempt
		double projtime = targpos.Length() / projspeed;
		leadpos = targpos + targvel*projtime + 0.5*targaccel*projtime*projtime;

		// second pass
		projtime = leadpos.Length() / projspeed;
		leadpos = targpos + targvel*projtime + 0.5*targaccel*projtime*projtime;
	} else {
		// default
		leadpos = targpos;
	}

	return leadpos.Normalized();
}

static int GetFlipMode(Ship *ship, const vector3d &relpos, const vector3d &relvel)
{
	double dist = relpos.Length();
	double vel = relvel.Dot(relpos) / dist;
	if (vel > 0.0 && vel*vel > 1.7 * ship->GetAccelRev() * dist) return 2;
	if (dist > 100000000.0) return 1;	// arbitrary
	return 0;
}

static void DrawAtmosphereSurface(Graphics::Renderer *renderer,
	const matrix4x4d &modelView, const vector3d &campos, float rad, Graphics::Material *mat)
{
	const int LAT_SEGS = 20;
	const int LONG_SEGS = 20;
	vector3d yaxis = campos.Normalized();
	vector3d zaxis = vector3d(1.0,0.0,0.0).Cross(yaxis).Normalized();
	vector3d xaxis = yaxis.Cross(zaxis);
	const matrix4x4d invrot = matrix4x4d::MakeRotMatrix(xaxis, yaxis, zaxis).InverseOf();

	renderer->SetTransform(modelView * matrix4x4d::ScaleMatrix(rad, rad, rad) * invrot);

	// what is this? Well, angle to the horizon is:
	// acos(planetRadius/viewerDistFromSphereCentre)
	// and angle from this tangent on to atmosphere is:
	// acos(planetRadius/atmosphereRadius) ie acos(1.0/1.01244blah)
	double endAng = acos(1.0/campos.Length())+acos(1.0/rad);
	double latDiff = endAng / double(LAT_SEGS);

	double rot = 0.0;
	float sinCosTable[LONG_SEGS+1][2];
	for (int i=0; i<=LONG_SEGS; i++, rot += 2.0*M_PI/double(LONG_SEGS)) {
		sinCosTable[i][0] = float(sin(rot));
		sinCosTable[i][1] = float(cos(rot));
	}

	/* Tri-fan above viewer */
	Graphics::VertexArray va(Graphics::ATTRIB_POSITION);
	va.Add(vector3f(0.f, 1.f, 0.f));
	for (int i=0; i<=LONG_SEGS; i++) {
		va.Add(vector3f(
			sin(latDiff)*sinCosTable[i][0],
			cos(latDiff),
			-sin(latDiff)*sinCosTable[i][1]));
	}
	renderer->DrawTriangles(&va, mat, Graphics::TRIANGLE_FAN);

	/* and wound latitudinal strips */
	double lat = latDiff;
	for (int j=1; j<LAT_SEGS; j++, lat += latDiff) {
		Graphics::VertexArray v(Graphics::ATTRIB_POSITION);
		float cosLat = cos(lat);
		float sinLat = sin(lat);
		float cosLat2 = cos(lat+latDiff);
		float sinLat2 = sin(lat+latDiff);
		for (int i=0; i<=LONG_SEGS; i++) {
			v.Add(vector3f(sinLat*sinCosTable[i][0], cosLat, -sinLat*sinCosTable[i][1]));
			v.Add(vector3f(sinLat2*sinCosTable[i][0], cosLat2, -sinLat2*sinCosTable[i][1]));
		}
		renderer->DrawTriangles(&v, mat, Graphics::TRIANGLE_STRIP);
	}
}

void SpaceStation::Render(const vector3d &viewCoords, const matrix4x4d &viewTransform)
{
	/* Well this is nice... */
	static int poo=0;
	if (!poo) {
		poo = 1;
		LmrGetModelsWithTag("advert", s_advertModels);
	}
	// it is silly to do this every render call
	//
	// random advert models in pFlag[16 .. 19]
	// station name in pText[0]
	// docking port in pText[1]
	MTRand rand;
	rand.seed(m_sbody->seed);
	
	LmrObjParams &params = GetLmrObjParams();
	/* random advert models */
	params.argStrings[4] = s_advertModels[rand.Int32(s_advertModels.size())]->GetName();
	params.argStrings[5] = s_advertModels[rand.Int32(s_advertModels.size())]->GetName();
	params.argStrings[6] = s_advertModels[rand.Int32(s_advertModels.size())]->GetName();
	params.argStrings[7] = s_advertModels[rand.Int32(s_advertModels.size())]->GetName();
	params.argStrings[0] = GetLabel().c_str();
	SetLmrTimeParams();

	for (int i=0; i<MAX_DOCKING_PORTS; i++) {
		params.argDoubles[ARG_STATION_BAY1_STAGE + i] = double(m_shipDocking[i].stage);
		params.argDoubles[ARG_STATION_BAY1_POS + i] = m_shipDocking[i].stagePos;
	}

	RenderLmrModel(viewCoords, viewTransform);
	
	/* don't render city if too far away */
	if (viewCoords.Length() > 1000000.0) return;

	// find planet Body*
	Planet *planet;
	{
		Body *_planet = GetFrame()->m_astroBody;
		if ((!_planet) || !_planet->IsType(Object::PLANET)) {
			// orbital spaceport -- don't make city turds
		} else {
			planet = static_cast<Planet*>(_planet);
		
			if (!m_adjacentCity) {
				m_adjacentCity = new CityOnPlanet(planet, this, m_sbody->seed);
			}
			m_adjacentCity->Render(this, viewCoords, viewTransform);
		}
	}
}

void Space::BodyNearFinder::GetBodiesMaybeNear(const vector3d &pos, double dist, BodyNearList &bodies) const
{
    if (m_bodyDist.empty()) return;

    const double len = pos.Length();

    std::vector<BodyDist>::const_iterator min = std::lower_bound(m_bodyDist.begin(), m_bodyDist.end(), len-dist);
    std::vector<BodyDist>::const_iterator max = std::upper_bound(min, m_bodyDist.end(), len+dist);

    while (min != max) {
        bodies.push_back((*min).body);
        ++min;
    }
}

/*
 * Function: SpawnShipNear
 *
 * Create a ship and place it in space near the given <Body>.
 *
 * > ship = Space.SpawnShip(type, body, min, max, hyperspace)
 *
 * Parameters:
 *
 *   type - the name of the ship
 *
 *   body - the <Body> near which the ship should be spawned
 *
 *   min - minimum distance from the body to place the ship, in Km
 *
 *   max - maximum distance to place the ship
 *
 *   hyperspace - optional table containing hyperspace entry information. If
 *                this is provided the ship will not spawn directly. Instead,
 *                a hyperspace cloud will be created that the ship will exit
 *                from. The table contains two elements, a <SystemPath> for
 *                the system the ship is travelling from, and the due
 *                date/time that the ship should emerge from the cloud.
 *
 * Return:
 *
 *   ship - a <Ship> object for the new ship
 *
 * Example:
 *
 * > -- spawn a ship 10km from the player
 * > local ship = Ship.SpawnNear("viper_police_craft", Game.player, 10, 10)
 *
 * Availability:
 *
 *   alpha 10
 *
 * Status:
 *
 *   experimental
 */
static int l_space_spawn_ship_near(lua_State *l)
{
    if (!Pi::game)
        luaL_error(l, "Game is not started");

    LUA_DEBUG_START(l);

    const char *type = luaL_checkstring(l, 1);
    if (! ShipType::Get(type))
        luaL_error(l, "Unknown ship type '%s'", type);

    Body *nearbody = LuaObject<Body>::CheckFromLua(2);
    float min_dist = luaL_checknumber(l, 3);
    float max_dist = luaL_checknumber(l, 4);

    SystemPath *path = 0;
    double due = -1;
    _unpack_hyperspace_args(l, 5, path, due);

    Ship *ship = new Ship(type);
    assert(ship);

    Body *thing = _maybe_wrap_ship_with_cloud(ship, path, due);

    // XXX protect against spawning inside the body
    Frame * newframe = nearbody->GetFrame();
    const vector3d newPosition = (MathUtil::RandomPointOnSphere(min_dist, max_dist)* 1000.0) + nearbody->GetPosition();

    // If the frame is rotating and the chosen position is too far, use non-rotating parent.
    // Otherwise the ship will be given a massive initial velocity when it's bumped out of the
    // rotating frame in the next update
    if (newframe->IsRotFrame() && newframe->GetRadius() < newPosition.Length()) {
        assert(newframe->GetParent());
        newframe = newframe->GetParent();
    }

    thing->SetFrame(newframe);;
    thing->SetPosition(newPosition);
    thing->SetVelocity(vector3d(0,0,0));
    Pi::game->GetSpace()->AddBody(thing);

    LuaObject<Ship>::PushToLua(ship);

    LUA_DEBUG_END(l, 1);

    return 1;
}

// check whether ship is at risk of colliding with frame body on current path
// return values:
//0 - no collision
//1 - below feature height
//2 - unsafe escape from effect radius
//3 - unsafe entry to effect radius
//4 - probable path intercept
static int CheckCollision(Ship *ship, const vector3d &pathdir, double pathdist, const vector3d &tpos, double endvel, double r)
{
	// ship is in obstructor's frame anyway, so is tpos
	if (pathdist < 100.0) return 0;
	Body *body = ship->GetFrame()->GetBodyFor();
	if (!body) return 0;
	vector3d spos = ship->GetPosition();
	double tlen = tpos.Length(), slen = spos.Length();
	double fr = MaxFeatureRad(body);

	// if target inside, check if direct entry is safe (30 degree)
	if (tlen < r) {
		double af = (tlen > fr) ? 0.5 * (1 - (tlen-fr) / (r-fr)) : 0.5;
		if (pathdir.Dot(tpos) > -af*tlen)
			if (slen < fr) return 1; else return 3;
		else return 0;
	}

	// if ship inside, check for max feature height and direct escape (30 degree)
	if (slen < r) {
		if (slen < fr) return 1;
		double af = (slen > fr) ? 0.5 * (1 - (slen-fr) / (r-fr)) : 0.5;
		if (pathdir.Dot(spos) < af*slen) return 2; else return 0;
	}

	// now for the intercept calc
	// find closest point to obstructor
	double tanlen = -spos.Dot(pathdir);
	if (tanlen < 0 || tanlen > pathdist) return 0;		// closest point outside path

	vector3d perpdir = (tanlen*pathdir + spos).Normalized();
	double perpspeed = ship->GetVelocity().Dot(perpdir);
	double parspeed = ship->GetVelocity().Dot(pathdir);
	if (parspeed < 0) parspeed = 0;			// shouldn't break any important case
	if (perpspeed > 0) perpspeed = 0;		// prevent attempts to speculatively fly through planets

	// find time that ship will pass through that point
	// get velocity as if accelerating from start or end, pick smallest
	double ivelsqr = endvel*endvel + 2*ship->GetAccelFwd()*(pathdist-tanlen);		// could put endvel in here
	double fvelsqr = parspeed*parspeed + 2*ship->GetAccelFwd()*tanlen;
	double tanspeed = sqrt(ivelsqr < fvelsqr ? ivelsqr : fvelsqr);
	double time = tanlen / (0.5 * (parspeed + tanspeed));		// actually correct?

	double dist = spos.Dot(perpdir) + perpspeed*time;		// spos.perpdir should be positive
	if (dist < r) return 4;
	return 0;
}

void GeoPatch::_UpdateVBOs() {
	if (m_needUpdateVBOs) {
		m_needUpdateVBOs = false;
		if (!m_vbo) glGenBuffersARB(1, &m_vbo);
		glBindBufferARB(GL_ARRAY_BUFFER, m_vbo);
		glBufferDataARB(GL_ARRAY_BUFFER, sizeof(GeoPatchContext::VBOVertex)*ctx->NUMVERTICES(), 0, GL_DYNAMIC_DRAW);
		double xfrac=0.0, yfrac=0.0;
		double *pHts = heights.Get();
		const vector3f *pNorm = &normals[0];
		const Color3ub *pColr = &colors[0];
		GeoPatchContext::VBOVertex *pData = ctx->vbotemp;
		for (int y=0; y<ctx->edgeLen; y++) {
			xfrac = 0.0;
			for (int x=0; x<ctx->edgeLen; x++) {
				const double height = *pHts;
				const vector3d p = (GetSpherePoint(xfrac, yfrac) * (height + 1.0)) - clipCentroid;
				clipRadius = std::max(clipRadius, p.Length());
				pData->x = float(p.x);
				pData->y = float(p.y);
				pData->z = float(p.z);
				++pHts;	// next height

				pData->nx = pNorm->x;
				pData->ny = pNorm->y;
				pData->nz = pNorm->z;
				++pNorm; // next normal

				pData->col[0] = pColr->r;
				pData->col[1] = pColr->g;
				pData->col[2] = pColr->b;
				pData->col[3] = 255;
				++pColr; // next colour

				++pData; // next vertex

				xfrac += ctx->frac;
			}
			yfrac += ctx->frac;
		}
		glBufferDataARB(GL_ARRAY_BUFFER, sizeof(GeoPatchContext::VBOVertex)*ctx->NUMVERTICES(), ctx->vbotemp, GL_DYNAMIC_DRAW);
		glBindBufferARB(GL_ARRAY_BUFFER, 0);
	}
}

void SystemView::PutOrbit(const Orbit *orbit, const vector3d &offset, const Color &color, double planetRadius)
{
	int num_vertices = 0;
	vector3f vts[100];
	for (int i = 0; i < int(COUNTOF(vts)); ++i) {
		const double t = double(i) / double(COUNTOF(vts));
		const vector3d pos = orbit->EvenSpacedPosTrajectory(t);
		vts[i] = vector3f(offset + pos * double(m_zoom));
		++num_vertices;
		if (pos.Length() < planetRadius)
			break;
	}

	if (num_vertices > 1) {
		// don't close the loop for hyperbolas and parabolas and crashed ellipses
		if ((orbit->GetEccentricity() > 1.0) || (num_vertices < int(COUNTOF(vts))))
			m_renderer->DrawLines(num_vertices, vts, color, LINE_STRIP);
		else
			m_renderer->DrawLines(num_vertices, vts, color, LINE_LOOP);
	}
}

void Body::UpdateFrame()
{
	if (!(m_flags & FLAG_CAN_MOVE_FRAME)) return;

	// falling out of frames
	if (m_frame->GetRadius() < GetPosition().Length()) {
		Frame *newFrame = GetFrame()->GetParent();
		if (newFrame) { 						// don't fall out of root frame
			Output("%s leaves frame %s\n", GetLabel().c_str(), GetFrame()->GetLabel().c_str());
			SwitchToFrame(newFrame);
			return;
		}
	}

	// entering into frames
	for (Frame* kid : m_frame->GetChildren()) {
		const vector3d pos = GetPositionRelTo(kid);
		if (pos.Length() >= kid->GetRadius()) continue;
		SwitchToFrame(kid);
		Output("%s enters frame %s\n", GetLabel().c_str(), kid->GetLabel().c_str());
		break;
	}
}

void Camera::DrawSpike(double rad, const vector3d &viewCoords, const matrix4x4d &viewTransform)
{
	// draw twinkly star-thing on faraway objects
	// XXX this seems like a good case for drawing in 2D - use projected position, then the
	// "face the camera dammit" bits can be skipped
	if (!m_renderer) return;

	const double newdist = m_zNear + 0.5f * (m_zFar - m_zNear);
	const double scale = newdist / viewCoords.Length();

	matrix4x4d trans = matrix4x4d::Identity();
	trans.Translate(scale*viewCoords.x, scale*viewCoords.y, scale*viewCoords.z);

	// face the camera dammit
	vector3d zaxis = viewCoords.Normalized();
	vector3d xaxis = vector3d(0,1,0).Cross(zaxis).Normalized();
	vector3d yaxis = zaxis.Cross(xaxis);
	matrix4x4d rot = matrix4x4d::MakeInvRotMatrix(xaxis, yaxis, zaxis);
	trans = trans * rot;

	m_renderer->SetDepthTest(false);
	m_renderer->SetBlendMode(BLEND_ALPHA_ONE);

	// XXX this is supposed to pick a correct light colour for the object twinkle.
	// Not quite correct, since it always uses the first light
	GLfloat col[4];
	glGetLightfv(GL_LIGHT0, GL_DIFFUSE, col);
	col[3] = 1.f;

	static VertexArray va(ATTRIB_POSITION | ATTRIB_DIFFUSE);
	va.Clear();

	const Color center(col[0], col[1], col[2], col[2]);
	const Color edges(col[0], col[1], col[2], 0.f);

	//center
	va.Add(vector3f(0.f), center);

	const float spikerad = float(scale*rad);

	// bezier with (0,0,0) control points
	{
		const vector3f p0(0,spikerad,0), p1(spikerad,0,0);
		float t=0.1f; for (int i=1; i<10; i++, t+= 0.1f) {
			const vector3f p = (1-t)*(1-t)*p0 + t*t*p1;
			va.Add(p, edges);
		}
	}
	{
		const vector3f p0(spikerad,0,0), p1(0,-spikerad,0);
		float t=0.1f; for (int i=1; i<10; i++, t+= 0.1f) {
			const vector3f p = (1-t)*(1-t)*p0 + t*t*p1;
			va.Add(p, edges);
		}
	}
	{
		const vector3f p0(0,-spikerad,0), p1(-spikerad,0,0);
		float t=0.1f; for (int i=1; i<10; i++, t+= 0.1f) {
			const vector3f p = (1-t)*(1-t)*p0 + t*t*p1;
			va.Add(p, edges);
		}
	}
	{
		const vector3f p0(-spikerad,0,0), p1(0,spikerad,0);
		float t=0.1f; for (int i=1; i<10; i++, t+= 0.1f) {
			const vector3f p = (1-t)*(1-t)*p0 + t*t*p1;
			va.Add(p, edges);
		}
	}

	glPushMatrix();
	m_renderer->SetTransform(trans);
	m_renderer->DrawTriangles(&va, Graphics::vtxColorMaterial, TRIANGLE_FAN);
	m_renderer->SetBlendMode(BLEND_SOLID);
	m_renderer->SetDepthTest(true);
	glPopMatrix();
}