Month: November 2021

Perspective & Orthogonal Projection Matrix

Projection = glm::perspective(g_fovy, g_aspect, g_zNear, g_zFar);

Projection = glm::ortho(-5.0f, 5.0f, -5.0f, 5.0f, g_zNear, g_zFar);

Camera & View Matrix

camera class를 사용하여 x/y/x축 카메라의 위치이동과 x/y/x축 카메라의 방향이동
F1&F2 – x축 카메라 위치이동
F3&F4 – y축 카메라 위치이동
F5&F6 – z축 카메라 위치이동
F7&F8 – x축 카메라 방향이동 (PITCH)
F9&F10 – y축 카메라 방향이동 (YAW)
HOME&END – z축 카메라 방향이동 (ROLL)

template <typename T, precision P>
GLM_FUNC_QUALIFIER tmat4x4<T, P> lookAt(tvec3<T, P> const & eye, tvec3<T, P> const & center, tvec3<T, P> const & up)
{
# if GLM_COORDINATE_SYSTEM == GLM_LEFT_HANDED
return lookAtLH(eye, center, up);
# else
return lookAtRH(eye, center, up);
# endif
}

template <typename T, precision P>
GLM_FUNC_QUALIFIER tmat4x4<T, P> lookAtRH
(
tvec3<T, P> const & eye,
tvec3<T, P> const & center,
tvec3<T, P> const & up
)
{
tvec3<T, P> const f(normalize(center – eye));
tvec3<T, P> const s(normalize(cross(f, up)));
tvec3<T, P> const u(cross(s, f));

tmat4x4<T, P> Result(1);
Result[0][0] = s.x;
Result[1][0] = s.y;
Result[2][0] = s.z;
Result[0][1] = u.x;
Result[1][1] = u.y;
Result[2][1] = u.z;
Result[0][2] =-f.x;
Result[1][2] =-f.y;
Result[2][2] =-f.z;
Result[3][0] =-dot(s, eye);
Result[3][1] =-dot(u, eye);
Result[3][2] = dot(f, eye);
return Result;
}

template <typename T, precision P>
GLM_FUNC_QUALIFIER tmat4x4<T, P> lookAtLH
(
tvec3<T, P> const & eye,
tvec3<T, P> const & center,
tvec3<T, P> const & up
)
{
tvec3<T, P> const f(normalize(center – eye));
tvec3<T, P> const s(normalize(cross(up, f)));
tvec3<T, P> const u(cross(f, s));

tmat4x4<T, P> Result(1);
Result[0][0] = s.x;
Result[1][0] = s.y;
Result[2][0] = s.z;
Result[0][1] = u.x;
Result[1][1] = u.y;
Result[2][1] = u.z;
Result[0][2] = f.x;
Result[1][2] = f.y;
Result[2][2] = f.z;
Result[3][0] = -dot(s, eye);
Result[3][1] = -dot(u, eye);
Result[3][2] = -dot(f, eye);
return Result;
}

Orthographic Projection

template <typename T>
 GLM_FUNC_QUALIFIER tmat4x4<T, defaultp> ortho
 (
  T left,
  T right,
  T bottom,
  T top,
  T zNear,
  T zFar
 )
 {
  tmat4x4<T, defaultp> Result(1);
  Result[0][0] = static_cast<T>(2) / (right - left);
  Result[1][1] = static_cast<T>(2) / (top - bottom);
  Result[2][2] = - static_cast<T>(2) / (zFar - zNear);
  Result[3][0] = - (right + left) / (right - left);
  Result[3][1] = - (top + bottom) / (top - bottom);
  Result[3][2] = - (zFar + zNear) / (zFar - zNear);
  return Result;
 }

Perspective Projection

 template <typename T>
 GLM_FUNC_QUALIFIER tmat4x4<T, defaultp> frustum
 (
  T left,
  T right,
  T bottom,
  T top,
  T nearVal,
  T farVal
 )
 {
  tmat4x4<T, defaultp> Result(0);
  Result[0][0] = (static_cast<T>(2) * nearVal) / (right - left);
  Result[1][1] = (static_cast<T>(2) * nearVal) / (top - bottom);
  Result[2][0] = (right + left) / (right - left);
  Result[2][1] = (top + bottom) / (top - bottom);
  Result[2][2] = -(farVal + nearVal) / (farVal - nearVal);
  Result[2][3] = static_cast<T>(-1);
  Result[3][2] = -(static_cast<T>(2) * farVal * nearVal) / (farVal - nearVal);
  return Result;
 }

http://www.songho.ca/opengl/gl_projectionmatrix.html