Implicit surface rendering via ray tracing
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/*
* Copyright (c) 2013-2021, NVIDIA CORPORATION. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* SPDX-FileCopyrightText: Copyright (c) 2013-2021 NVIDIA CORPORATION
* SPDX-License-Identifier: Apache-2.0
*/
//--------------------------------------------------------------------
#pragma once
#include <nvh/nvprint.hpp>
#include <nvmath/nvmath.h>
#include <cmath>
using namespace nvmath;
//------------------------------------------------------------------------------------------
/// \struct InertiaCamera
/// \brief Struct that offers a camera moving with some inertia effect around a target point
///
/// InertiaCamera exposes a mix of pseudo polar rotation around a target point and
/// some other movements to translate the target point, zoom in and out.
///
/// Either the keyboard or mouse can be used for all of the moves.
//------------------------------------------------------------------------------------------
struct InertiaCamera
{
vec3f curEyePos, curFocusPos, curObjectPos; ///< Current position of the motion
vec3f eyePos, focusPos, objectPos; ///< expected posiions to reach
float tau; ///< acceleration factor in the motion function
float epsilon;
float eyeD;
float focusD;
float objectD;
mat4f m4_view; ///< transformation matrix resulting from the computation
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
InertiaCamera(const vec3f eye = vec3f(0.0f, 1.0f, -3.0f), const vec3f focus = vec3f(0, 0, 0), const vec3f object = vec3f(0, 0, 0))
{
epsilon = 0.001f;
tau = 0.2f;
curEyePos = eye;
eyePos = eye;
curFocusPos = focus;
focusPos = focus;
curObjectPos = object;
objectPos = object;
eyeD = 0.0f;
focusD = 0.0f;
objectD = 0.0f;
m4_view.identity();
mat4f Lookat = nvmath::look_at(curEyePos, curFocusPos, vec3f(0, 1, 0));
m4_view *= Lookat;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void rotateH(float s, bool bPan = false)
{
vec3f p = eyePos;
vec3f o = focusPos;
vec3f po = p - o;
float l = po.norm();
vec3f dv = cross(po, vec3f(0, 1, 0));
dv *= s;
p += dv;
po = p - o;
float l2 = po.norm();
l = l2 - l;
p -= (l / l2) * (po);
eyePos = p;
if(bPan)
focusPos += dv;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void rotateV(float s, bool bPan = false)
{
vec3f p = eyePos;
vec3f o = focusPos;
vec3f po = p - o;
float l = po.norm();
vec3f dv = cross(po, vec3f(0, -1, 0));
dv.normalize();
vec3f dv2 = cross(po, dv);
dv2 *= s;
p += dv2;
po = p - o;
float l2 = po.norm();
if(bPan)
focusPos += dv2;
// protect against gimbal lock
if(std::fabs(dot(po / l2, vec3f(0, 1, 0))) > 0.99)
return;
l = l2 - l;
p -= (l / l2) * (po);
eyePos = p;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void move(float s, bool bPan)
{
vec3f p = eyePos;
vec3f o = focusPos;
vec3f po = p - o;
po *= s;
p -= po;
if(bPan)
focusPos -= po;
eyePos = p;
}
//------------------------------------------------------------------------------------
/// \brief simulation step to call with a proper time interval to update the animation
//------------------------------------------------------------------------------------
bool update(float dt)
{
if(dt > (1.0f / 60.0f))
dt = (1.0f / 60.0f);
bool bContinue = false;
static vec3f eyeVel = vec3f(0, 0, 0);
static vec3f eyeAcc = vec3f(0, 0, 0);
eyeD = nv_norm(curEyePos - eyePos);
if(eyeD > epsilon)
{
bContinue = true;
vec3f dV = curEyePos - eyePos;
eyeAcc = (-2.0f / tau) * eyeVel - dV / (tau * tau);
// integrate
eyeVel += eyeAcc * vec3f(dt, dt, dt);
curEyePos += eyeVel * vec3f(dt, dt, dt);
}
else
{
eyeVel = vec3f(0, 0, 0);
eyeAcc = vec3f(0, 0, 0);
}
static vec3f focusVel = vec3f(0, 0, 0);
static vec3f focusAcc = vec3f(0, 0, 0);
focusD = nv_norm(curFocusPos - focusPos);
if(focusD > epsilon)
{
bContinue = true;
vec3f dV = curFocusPos - focusPos;
focusAcc = (-2.0f / tau) * focusVel - dV / (tau * tau);
// integrate
focusVel += focusAcc * vec3f(dt, dt, dt);
curFocusPos += focusVel * vec3f(dt, dt, dt);
}
else
{
focusVel = vec3f(0, 0, 0);
focusAcc = vec3f(0, 0, 0);
}
static vec3f objectVel = vec3f(0, 0, 0);
static vec3f objectAcc = vec3f(0, 0, 0);
objectD = nv_norm(curObjectPos - objectPos);
if(objectD > epsilon)
{
bContinue = true;
vec3f dV = curObjectPos - objectPos;
objectAcc = (-2.0f / tau) * objectVel - dV / (tau * tau);
// integrate
objectVel += objectAcc * vec3f(dt, dt, dt);
curObjectPos += objectVel * vec3f(dt, dt, dt);
}
else
{
objectVel = vec3f(0, 0, 0);
objectAcc = vec3f(0, 0, 0);
}
//
// Camera View matrix
//
vec3f up(0, 1, 0);
m4_view.identity();
mat4f Lookat = nvmath::look_at(curEyePos, curFocusPos, up);
m4_view *= Lookat;
return bContinue;
}
//------------------------------------------------------------------------------
/// \brief Call this function to update the camera position and targets position
/// \arg *reset* set to true will directly update the actual positions without
/// performing the animation for transitioning.
//------------------------------------------------------------------------------
void look_at(const vec3f& eye, const vec3f& center /*, const vec3f& up*/, bool reset = false)
{
eyePos = eye;
focusPos = center;
if(reset)
{
curEyePos = eye;
curFocusPos = center;
vec3f up(0, 1, 0);
m4_view.identity();
mat4f Lookat = nvmath::look_at(curEyePos, curFocusPos, up);
m4_view *= Lookat;
}
}
//------------------------------------------------------------------------------
/// \brief debug information of camera position and target position
/// Particularily useful to record a bunch of positions that can later be
/// reuses as "recorded" presets
//------------------------------------------------------------------------------
void print_look_at(bool cppLike = false)
{
if(cppLike)
{
LOGI("{vec3f(%.2f, %.2f, %.2f), vec3f(%.2f, %.2f, %.2f)},\n", eyePos.x, eyePos.y, eyePos.z, focusPos.x,
focusPos.y, focusPos.z);
}
else
{
LOGI("%.2f %.2f %.2f %.2f %.2f %.2f 0.0\n", eyePos.x, eyePos.y, eyePos.z, focusPos.x, focusPos.y, focusPos.z);
}
}
};