Questions tagged [glm]

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Converting points, vectors, normals between world and object space for a ray tracer gives weird results

I'm writing a ray tracer but having trouble converting rays and normals between world space and object space. I am creating a Ray, then transforming it with transformation matrices, calculating ...
Cedric's user avatar
  • 13
2 votes
0 answers
160 views

What is the projection matrix of reverse (Byzantine) perspective?

I would like to construct a projection matrix for reverse perspective. I'm using OpenGL and tried to modify concepts from this excelent tutorial. I came up with: $$ \begin{bmatrix} 2\frac{(near-M)}{...
Peter's user avatar
  • 21
4 votes
1 answer
414 views

Three quaternions interpolation with barycentric coordinates

I have three quaternions A, B, C. I also have a 3D vector P which describes the barycentric coordinate to interpolate. I want to interpolate the three quaternions with respect to the barycentric ...
Thomas's user avatar
  • 1,245
0 votes
1 answer
92 views

Wrong reflection

Here is a youtube video showing my problem: youtube.com/watch?v=y8J7VhS2pkM I think I'm either doing the texture lookup on the reflection texture wrong, or the reflection or view matrix is somehow ...
Martin Gerhardy's user avatar
-1 votes
2 answers
767 views

How can i wrap the earth image around a 3D Sphere using OpenGL, GLFW, GLAD, GLM?

Please help me out with this thing and currently i am a little more than a beginner so please tell me in that context. i don't need any obsolete methods for creating this like using GLUT or GLEW.can ...
bhagya731's user avatar
0 votes
0 answers
790 views

How to rotate an object in OpenGL on the X, Y and Z axis on its local coordinates?

I've read multiple tutorials, but I still can't understand how do I properly rotate an object in 3D space on all 3 axis at once. For example, I'd like to give the object a pitch of 60 degrees, yaw of ...
John's user avatar
  • 101
-1 votes
1 answer
2k views

Difficulty including GLM into Visual Studio with OpenGL

I have been trying to implement GLM (math library) into Visual Studio with OpenGL. I have followed and watched many online resources that point me to include only the GLM folder inside the ...
adam8cw's user avatar
1 vote
0 answers
1k views

360 degrees rotation around x axis

How do we rotate the camera around x axis 360 degrees, without having to flip the axis, meaning without having the strange flip after we go over +-90 degrees on <...
Test's user avatar
  • 31
1 vote
1 answer
237 views

My (ADS) shader doesn't render the light direction correctly

This is what I'm doing: vertex shader: ...
Charlie's user avatar
  • 203
1 vote
1 answer
513 views

Am I passing the correct matrices for my shader? openGL/C++

On page 89 of David Wolff - OpenGL 4.0 Shading Language Cookbook book, it suggests a way to set up up a Phong shader in the fragment stage. It lists some different matrices to pass via uniform, and I ...
Charlie's user avatar
  • 203
2 votes
0 answers
167 views

With OpenGL, is it correct to apply model transformation to rotate the camera?

Having taken a basic CG course, I remember that transformations are relative, so rotating the camera is identical to rotating the view in the opposite direction. Right now I want to implement camera ...
iksemyonov's user avatar
4 votes
1 answer
8k views

understanding glm::perspective vs glm::ortho

I'm new to computer graphics. I played around with OpenGL and now am trying out Vulkan. Basically what I want to do, in 2D is have an 800x800 window, and I want that to represent 800 meters by 800 ...
mikeglaz's user avatar
  • 269
11 votes
4 answers
13k views

Multiple viewports with modern OpenGL?

I use SDL2. Currently my only shader has a MVP matrix, and transforms the points with it. I calculate my View and Projection matrix for a camera with GLM: ...
Tudvari's user avatar
  • 313
3 votes
1 answer
6k views

Screen to World coordinates glm::unProject

I'm having some trouble trying to figure out how to go from a coordinate on the screen, to 3D world coordinates on a plane. My case is as seen on the picture further down. World origin is in the ...
remi000's user avatar
  • 240
3 votes
1 answer
709 views

Ray-tracing the Cornell Box results in really inconsistent image

So I have a vector of glm::vec3 containing the triangles for the classic Cornell Box called triangles. The Draw method casts a ray for each pixel on the screen and ...
swedish_fisk's user avatar
24 votes
1 answer
24k views

Get vector length with GLM

I am quite confused over how GLM library is behaving or I am using it improperly. glm::vec2 testVec(6,-4); float len = testVec.length(); I get the value ...
sajis997's user avatar
  • 1,279