perspective

问题 I made a small example for myself to play around with OpenCVs wrapPerspective, but the output is not completely as I expected. My input is a bar at an 45° angle. I want to transform it so that it's vertically aligned / at an 90° angle. No problem with that. However, what I don't understand is that everything around the actual destination points is black. The reason I don't understand this is, that actually only the transformation matrix gets passed to the wrapPerspective function, not the

问题 I tried to understand the mathematics behind the projection matrix and I found this page. The matrix from this page: I found this matrix is similar to the matrix of Xna. I understood how they got to m33 and m44 columns of the matrix, but how they got to m11 and m22? And I didn't understand why I have to give the aspect ratio if I already give the field of view angle. The last thing I want to know is: what is the equation for transfaring from ndc space to window space and how they get to this

问题 I'm packaging my own Eclipse product. I'm including a third party plugin, PluginA, whose menu contribution is only displayed when the active perspective is Debug. I'd like this menu to be displayed also in a perspective I've created, MyPerspective, from my own plugin, PluginB. I can't modify PluginA, but I can see the plugin.xml manifest, shown below, which shows how it configures it's menus. Its using the menu's visibleWhen attribute and checking the activePerspective is equal to

问题 I've just discovered FLTK and I made a makefile for my test. Here is my makefile: ################ template makefile ############## # We don't know what compiler to use to build fltk on this machine - but fltk-config does... CC = $(shell fltk-config --cc) CXX = $(shell fltk-config --cxx) # Set the flags for compiler: fltk-config knows the basic settings, then we can add our own... CFLAGS = $(shell fltk-config --cflags) CXXFLAGS = $(shell fltk-config --cxxflags) -I/System/Library/Frameworks

问题 I have two boxes with 3d transformation (rotationY). Each have almost the same values, one perspective looks fine, the other kinda wrong but still have some correct perspective. The first box at the top side does not protrude, but it have a perspective view yet. Also the 3° the container is 200% bigger The second box do a beautiful 3d effect. Here I made the example of what I'm trying to explain. $(".eye").on('click', function () { $( '.man' ).toggleClass('open'); }) * { padding: 0; margin: 0

问题 I am trying to find the equivalent point from one triangle to another. Ideally I want to be able to give the 3 points of triangle A and the 3 points of triangle B which will then calculate the transform matrix which I can apply to the point afterwards to find the equivalent point. I have found a few JavaScript libraries/methods for this, but they all use quadrilaterals rather than triangles and I am not sure what to do to apply to a triangle instead. 回答1: Three point pairs can define affine

来源： https://stackoverflow.com/questions/57431060/how-to-calculate-angle-of-rotation-to-make-width-fit-desired-size-in-perspective

来源： https://stackoverflow.com/questions/57431060/how-to-calculate-angle-of-rotation-to-make-width-fit-desired-size-in-perspective

问题 I have a code that given an image does the effect of perspective in 3D. This is the result: This is the code: .thumb { margin: 100px; perspective: 1000px; width: 1920px; height: 1200px; } .thumb a { --bg-pseudo: rotateY(120deg); /*Modificar transform */ --bg-pseudo2: --bg-pseudo2', '-5px -15px 45px 130px rgba(0, 0, 0, 0.3); /*modificar box-shadow */ display: block; width: 100%; height: 100%; background-image: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)),url('https://www.wallpaperk

问题 I have a code that given an image does the effect of perspective in 3D. This is the result: This is the code: .thumb { margin: 100px; perspective: 1000px; width: 1920px; height: 1200px; } .thumb a { --bg-pseudo: rotateY(120deg); /*Modificar transform */ --bg-pseudo2: --bg-pseudo2', '-5px -15px 45px 130px rgba(0, 0, 0, 0.3); /*modificar box-shadow */ display: block; width: 100%; height: 100%; background-image: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)),url('https://www.wallpaperk