reactphysics3d/testbed/opengl-framework/src/Camera.cpp
2015-04-08 20:47:55 +02:00

98 lines
3.9 KiB
C++

/********************************************************************************
* OpenGL-Framework *
* Copyright (c) 2013 Daniel Chappuis *
*********************************************************************************
* *
* This software is provided 'as-is', without any express or implied warranty. *
* In no event will the authors be held liable for any damages arising from the *
* use of this software. *
* *
* Permission is granted to anyone to use this software for any purpose, *
* including commercial applications, and to alter it and redistribute it *
* freely, subject to the following restrictions: *
* *
* 1. The origin of this software must not be misrepresented; you must not claim *
* that you wrote the original software. If you use this software in a *
* product, an acknowledgment in the product documentation would be *
* appreciated but is not required. *
* *
* 2. Altered source versions must be plainly marked as such, and must not be *
* misrepresented as being the original software. *
* *
* 3. This notice may not be removed or altered from any source distribution. *
* *
********************************************************************************/
// Libraries
#include "Camera.h"
#include "definitions.h"
#include <cmath>
// Namespaces
using namespace openglframework;
// Constructor
Camera::Camera() : Object3D() {
// Set default values
mFieldOfView = 45.0f;
mSceneRadius = 1.0f;
mNearPlane = 0.1f;
mFarPlane = 10.0f;
mWidth = 1;
mHeight = 1;
// Update the projection matrix
updateProjectionMatrix();
}
// Destructor
Camera::~Camera() {
}
// Update the projection matrix
void Camera::updateProjectionMatrix() {
// Compute the aspect ratio
float aspect = float(mWidth) / float(mHeight);
float top = mNearPlane * tan((mFieldOfView / 2.0f) * (float(PI) / 180.0f));
float bottom = -top;
float left = bottom * aspect;
float right = top * aspect;
float fx = 2.0f * mNearPlane / (right - left);
float fy = 2.0f * mNearPlane / (top - bottom);
float fz = -(mFarPlane + mNearPlane) / (mFarPlane - mNearPlane);
float fw = -2.0f * mFarPlane * mNearPlane / (mFarPlane - mNearPlane);
// Recompute the projection matrix
mProjectionMatrix = Matrix4(fx, 0, 0, 0,
0, fy, 0, 0,
0, 0, fz, fw,
0, 0, -1, 0);
}
// Translate the camera go a given point using the dx, dy fraction
void Camera::translateCamera(float dx, float dy, const Vector3& worldPoint) {
// Transform the world point into camera coordinates
Vector3 pointCamera = mTransformMatrix.getInverse() * worldPoint;
// Get the depth
float z = -pointCamera.z;
// Find the scaling of dx and dy from windows coordinates to near plane coordinates
// and from there to camera coordinates at the object's depth
float aspect = float(mWidth) / float(mHeight);
float top = mNearPlane * tan(mFieldOfView * PI / 360.0f);
float right = top * aspect;
// Translate the camera
translateLocal(Vector3(2.0f * dx * right / mNearPlane * z,
-2.0f * dy * top / mNearPlane * z,
0.0f));
}