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    Generating normal map

    Hello, I'd like to know how to generate normal map for a particular image. I know there's texture tool for adobe photoshop. I'd like to write code that can be used to generate normal maps for image.
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    But what happened when I don't explicitly define...

    But what happened when I don't explicitly define the mipmap levels:





    Will OpenGL generate a number of mipmap level automatically?
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    Question on Cube Map

    I've a very simple question on Cube Mapping. In cube map, I found six images corresponding to the six sides of a cube. Why the images are set together? What is the difference if six different images...
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    Question on Mipmapping

    Hello, I've some basic questions on mipmapping. I found that level parameter in glTexImage2D is set to '0' when we'd like to generate mipmap. For example:



    Is it by default OpenGL taking care...
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    3D Texture

    I'm trying to do the volume texture example in OpenGL Programming Guide 8th Edition (Chapter 6) using DevIL, but it doesn't show anything. Has anyone made that program working? I don't know what's...
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    That's what I was about to ask, I'm using OpenGL...

    That's what I was about to ask, I'm using OpenGL version 4.3 and it seems it doesn't matter whether the border is set to 0 or 1. Why?
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    Incresing texture border width

    Hello, I know the default border can be set as follow:




    But I'd like to know how to increase or decrease the border width?

    Thanks.
  8. some question about texturing using meshlab

    Hello, I'm trying to generate texture coordinates using meshlab for an obj model. Now the way I'm following is as follows:


    Filters > Texture > Parameterization: Trivial Per-Triangle or...
  9. Thanks for the clarification.

    Thanks for the clarification.
  10. Do we always need to normalize the normals

    Just a simple question, do we always need to normalize normals? Suppoe, when we calculate normal from triangle, is it mandatory to normalize the normals?
  11. Hello, just asking for another clarification. Do...

    Hello, just asking for another clarification. Do I need to always bind the base tetrahedron, hexagon or octahedron in a unit sphere by normalizing the vertices? Why?
    Thank you.
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    Thank you! But I don't understand the following:...

    Thank you! But I don't understand the following:



    Why do I need to multiply by FOV? Also it is considering right and up only?

    I'm also confused with the following:


    How can I calculate...
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    Thank you so much again. But I still have...

    Thank you so much again. But I still have question. For 2D texture, coordinate will range from (0,0) to (1,1), Why is it not the same for 3D texture, i.e. (0,0,0) to (1,1,1).
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    Thank you again! For 2D texture, I think I need...

    Thank you again! For 2D texture, I think I need to do as follows:



    Am I doing right? Can anyone also give me explanation about generating 3D texture coordinates for a sphere as well.

    Thanks...
  15. Thank you so much for the clarification GClements.

    Thank you so much for the clarification GClements.
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    Parametric model of a sphere

    A sphere centered at origin can be defined parametrically defined as follows:

    x = r cos(theta) cos(phi)
    y = r cos(theta) sin(phi)
    z = r sin(theta)


    Can the corresponding normal...
  17. Some clarification needed about modeling a sphere through sub division

    Hello, I am going through some codes regarding generating sphere from continuous sub division. It starts from a simple tetrahedron bounded within a sphere. Next, each face of the tetrahedron is...
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    gluUnProject

    Hello, is gluUnProject is the only method to find the x, y, z coordinate of the mouse or there is other method. Thank you.
  19. Thank you. I keep on trying, but still unclear...

    Thank you. I keep on trying, but still unclear what's going wrong. In some java program, I found that some 'flip' function is used for glBufferSubData. What does it mean in C or C++? I am worried I...
  20. Thanks for the reply. I've tried with same...

    Thanks for the reply. I've tried with same timesteps, but output not the same. I think, I could not update properly using glBufferSubData. But I couldn't figure out the errors. I have done as...
  21. Some clarification about glBufferSubData and glMapBuffer

    Hello, I'm trying to update my object (vertices) using timerfunc. I have done the update using both glMapBuffer and glBufferSubData. Now here, vertex update is a function of time (sine function)....
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    I understand, this is just offset in the bmp file...

    I understand, this is just offset in the bmp file header.
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    A simple question

    Hello, I've a simple question. I'm going through some code related with writing a bmp image file.

    In the following code, what does 'filesize>>8' imply? How is it used in a bmp file?



    Thanks.
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    Thanks again for the clarification. I think Phong...

    Thanks again for the clarification. I think Phong shading (without shader) can be performed using ray tracing. Isn't it?
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    Thanks a lot for the reply. I need some...

    Thanks a lot for the reply. I need some explanation. You mentioned about multitexturing. But what about when no texture is applied. Is per pixel normal calculated in the application and then color...
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