Contents
How does mouse pick work in OpenGL 4?
Anton Gerdelan. Last Updated 2 October 2016 It can be useful to click on, or “pick” a 3d object in our scene using the mouse cursor. One way of doing this is to project a 3d ray from the mouse, through the camera, into the scene, and then check if that ray intersects with any objects. This is usually called ray casting.
How to select an object using OpenGL-codeproject?
The first object that intersects with the ‘ray’ is the one being clicked on. To implement this properly you need a good matrix class and a good understanding of the model and projection transformations.
What can you do with Ray picking in OpenGL?
With ray picking we usually simplify a scene into bounding spheres or boxes. This makes the calculation a bit easier than testing all of the individual triangles. We don’t need to create a 3d sphere out of triangles that can be rendered; we just represent the sphere as a simple function.
How to run 2 different OpenGL objects in one dialogbox?
IDC_STATIC1 is a first OpenGL objects Scene window. IDC_STATIC2 is a second OpenGL objects Scene window. IDC_STATIC1 and IDC_STATIC2 ,they are placed on IDD_DIALOG1. Re: How to run 2 different (or same) OpenGL objects in one DialogBox? for more information!
How do you pick a ray in OpenGL?
It’s just for demo purpose. First, we need to find a ray which starts at the camera and goes “through the mouse”. This is done in the ScreenPosToWorldRay () function. First, we find the ray’s start and end position in Normalized Device Coordinates.
How to pick a ray from the mouse coordinates?
Assign each object you want to pick a unique color, render the objects with these colors and finally read out the color from the framebuffer under the mouse pointer. EDIT: If the question is how to construct the ray from the mouse coordinates you need the following: a projection matrix P and the camera transform C.
How to debug the selection function in OpenGL?
A good technique for debugging picking or selection code is not to call glRenderMode (GL_SELECT). Simply comment out this function call in your code. The result is instead of performing a selection, your code will render the contents of the pick box to your window.