glm-math

问题 The basic aim of my code is just to rotate a few points around the z-axis. However, after trying to initialise a rotation matrix using glm::rotate(m4, a, v3) and trying to check its components, a quick printf outputs some 1 800 000 000.0000000... for each element. I believe this is not the correct functionality.~ Note: I am not asking about the maths behind spatial transformations. They are clear to me. Code in essence: int main(int argc, char **argv){ InitGL(); // openGL, GLFW..

问题 I found a lot cases to create multiple objects by one single vertices array. And then through transform to get different ones, such as Draw 2 cubes in OpenGL using GLM and Cant draw multiple objects in opengl. But what I want is to create complete diff objects by complete diff vertices arrays. A typical case is http://www.spacesimulator.net/wiki/index.php?title=Tutorials:Matrices_%28OpenGL3.3%29. How to implement it by GLM? I tried to find some example codes. 回答1: Next code are a complete

问题 I'm trying to draw an element always facing camera. I've read some articles about billboard in shaders, the problem is that I need to compute rotation out of shaders and with different objects (circles, square, mesh, …). So, I'm trying to compute model's rotation only (not matrix, something similar to Transform.LookAt in Unity engine) but I don't know how to do, here is what I've got: // Camera data mat4 viewMatrix = camera->getMatrix(); vec3 up = {viewMatrix[0][1], viewMatrix[1][1],

问题 I'm trying to draw an element always facing camera. I've read some articles about billboard in shaders, the problem is that I need to compute rotation out of shaders and with different objects (circles, square, mesh, …). So, I'm trying to compute model's rotation only (not matrix, something similar to Transform.LookAt in Unity engine) but I don't know how to do, here is what I've got: // Camera data mat4 viewMatrix = camera->getMatrix(); vec3 up = {viewMatrix[0][1], viewMatrix[1][1],

问题 I'm trying to draw an element always facing camera. I've read some articles about billboard in shaders, the problem is that I need to compute rotation out of shaders and with different objects (circles, square, mesh, …). So, I'm trying to compute model's rotation only (not matrix, something similar to Transform.LookAt in Unity engine) but I don't know how to do, here is what I've got: // Camera data mat4 viewMatrix = camera->getMatrix(); vec3 up = {viewMatrix[0][1], viewMatrix[1][1],

问题 I read this tutorial, https://learnopengl.com/Getting-started/Transformations At the end, above the last picture, it says: glm::mat4 trans; trans = glm::translate(trans, glm::vec3(0.5f, -0.5f, 0.0f)); trans = glm::rotate(trans, (float)glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f)); I do not know what is the final trans values is, it is translate * rotate or rotate * translate ? Here we first rotate the container around the origin (0,0,0) and once it's rotated, we translate its rotated version to

问题 I've been reading other posts about how to rotate objects around a point in OpenGL by translating the pivot to the origin, rotating, and the translating back. However, I can't seem to get it working. I have a cube and am using glm::perspective and glm::lookAt to generate the projection and view matrices. glm::mat4 Projection = glm::perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f); // Camera matrix glm::mat4 View = glm::lookAt( glm::vec3(0,3.5,-5), glm::vec3(0,0,0), glm::vec3(0,1,0) ); // Model

问题 So I've been having trouble with a camera I've implemented in OpenGL and C++ using the GLM library. The type of camera I'm aiming for is a fly around camera which will allow easy exploration of a 3D world. I have managed to get the camera pretty much working, it's nice and smooth, looks around and the movement seems to be nice and correct. The only problem I seem to have is that the rotation along the camera's X and Y axis (looking up and down) introduces some rotation about it's Z axis. This

问题 The OpenGL maths library(GLM) uses the following algorithm to compute the translation matrix: //taken from source code template<typename T, qualifier Q> GLM_FUNC_QUALIFIER mat<4, 4, T, Q> translate(mat<4, 4, T, Q> const& m, vec<3, T, Q> const& v) { mat<4, 4, T, Q> Result(m); Result[3] = m[0] * v[0] + m[1] * v[1] + m[2] * v[2] + m[3]; return Result; } (Here the vector v is a 3 dimensional vector and the matrix m is a 4X4 matrix, since we're using homogeneous coordinates the vector v is also 4

问题 This code sample here: import QtQuick 2.0 Item { width: 200; height: 200 Rectangle { width: 100; height: 100 anchors.centerIn: parent color: "#00FF00" Rectangle { color: "#FF0000" width: 10; height: 10 anchors.top: parent.top anchors.right: parent.right } } } Will produce this output: Now I want to apply a 3D rotation from the center of this green rectangle. First, I want to rotate on X by -45 degrees (bowing down), then on Y by -60 degrees (turning left). I used the following c++ code