Questions tagged [picking]
149 questions
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Unable to mouse pick a quad rendered in a framebuffer
Struggling to mouse pick a point/quad. I believe I am either using coordinates in the wrong space or perhaps not accounting for the framebuffer's position/size (it's a sub window of the main window).
Tried converting to various different coordinate…
Jack
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2 answers
Matplotlib pick event from multiple series
I am doing a scatterplot where I want to click on the individual points to do something. This is like the existing example code.
https://matplotlib.org/examples/event_handling/pick_event_demo.html
I have implemented an on_pick method
def…
opus111
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iPhone OpenGL ES: glReadPixels not working
I trying to implement a simple picking function using glReadPixels however when I click on an object that is 1 colour, I get different values back depending on where I clicked on that object? There not special lighting etc? Whats going on? …
Burf2000
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Ray picking with gluUnProject()
I have a quad on the y = -50 plane. At the moment, all I want to do is obtain the coordinates of a mouse click on the quad. I've managed to do this to a limited extent. The problem is that the transformations I applied when drawing the quad…
zoo
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Cesium Get color of picked entity to compare
Is there any way to get color of picked entity on Cesium?
Basically, I need to check the color of clicked entity, if its blue, change it to red and vice-versa.
Is there any way to achieve this? Thanks in advance.
meen
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2 answers
is it possible to render to framebuffer object outside of main render loop
i am using a separate framebuffer object for color picking 2d objects in opengl. i am curious if its possible to only draw to the framebuffer and read the color when needed.
what i am doing now is in the main render loop i draw the scene to the…
cuatro
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OPEN GL ES 1.0. World coordinates to screen coordinates
For 3d-picking I planned to do this:
-Get touch coordinates (x, y)
-Choose vertex from vertex buffer of my model (xM, yM, zM).
-Then project by my own hands (xM, yM, zM) on the screen coords
(xM, yM, zM) ---> (xP, yP, ...)
and then check match (for…
mihael.t
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Incorrect values written in stencil buffer
I am trying to pick objects on mouse click. For this I have followed this tutorial, and tried to use the stencil buffer for this purpose.
Inside "game" loop I am trying to draw 10 (5 pairs) 'pick'able triangles as follows:
...
glClearColor(red,…
Sayan Pal
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GlunUnproject moving object with the mouse
I'm trying to move objects with the mouse using the Gluunproject method with openGL 2.1 , but i'm really struggling here; here's the code i wrote :
int viewport[4];
double modelview[16],
projection[16],
X1, Y1, Z1;
double realY;
…
HdjoWattever
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Picking with glRenderMode
I try to do OpenGL picking so I followed this post (OpenGL Picking on Selection Mode ) which seems to have a working solution but I can't make mine work. I have a 3D textured polygon in my scene and I would like to know when I click on it.
Here is…
SteveTJS
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2 answers
SharpDX GetPickRay issues
I am trying to get a picking ray from the current camera position/view so I can use it to select objects in the 3d world. The issue is that when I move the camera around, the ray becomes incorrect. Am I doing something wrong or is it a floating…
ManIkWeet
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"objects map" in opengl
To keep it short: As we all know, opengl draws many triangles on the screen.
What I want to know:
If opengl draws triangles, it has to know, which triangle belongs to which pixel on the screen, right?
Can I get this information too? For example call…
bricklore
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Why Do I Always Zoom in When Picking? (OpenGL)
I have the following code:
#define GLUT_DISABLE_ATEXIT_HACK
#include
#include
#include
#include
GLfloat ctrlptsBezier[4][4][3] =
{
{
{-2.0, -2.0, 1.0},
{-0.5, -2.0, 0.0},
{0.5,…
Rome_Leader
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Picking objects in OpenGl ,using C#
i'm working with opengl using C#(using TaoFrame work ) ,the thing is that i want to draw
2 objects on screen (rectangle for example ),the main goal of my Question is, how to press the mouse button so i can select one object to make it move .…
Wazzz
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4 answers
How do you determine when an object is drawn on-screen in OpenGL?
I'm extremely new to OpenGL. I'm writing a program that displays flying 3D text on screen. I need to know when certain text string appears (drawn) onto the screen and are visible to the user. The program needs to identify which text strings are…
Harry
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