Author: kpark

ShadedTeapotCylinderSphere (with moving light source)
11.OpenGLShadedGLUT

ShadedTeapot (with different materials)
11.OpenGLMaterialTeapot

Ambient/Diffuse/Specular (From left to right: diffuse; ambient; diffuse + ambient; diffuse+ambient+specular) from lighthouse3d.com

Light sources (From left to right: directional; point; and spotlights) from lighthouse3d.com

Z-fighting, also called stitching, is a phenomenon in 3D rendering that occurs when two or more primitives have similar values in the z-buffer.  This problem is usually caused by limited sub-pixel precision and floating point and fixed point round-off errors. https://en.wikipedia.org/wiki/Z-fighting

There is very high precision at the near plane, but very little precision at the far plane. If the range [-n, -f] is getting larger, it causes a depth precision problem (z-fighting); a small change of z_e around the far plane does not affect on z_n value. The distance between n and f should be short as possible to minimize the depth buffer precision problem.

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

lab10-GeometryPositionColorOrthoPerspective

lab10-GeometryPositionColorOrientationCamera

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)

http://dis.dankook.ac.kr/lectures/cg12/entry/OpenGL-Camera

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;
}