mipmaps

Does it make sense to use own mipmap creation algorithm for OpenGL textures?

I was wondering if the quality of texture mipmaps would be better if I used my own algorithm for pre-generating them, instead of the built-in automatic one. I'd probably use a slow but pretty algorithm, like Lanczos resampling. Does it make sense? Will I get any quality gain on modern graphics cards? ...

OpenGL - Copy texture from screen smaller than that screen.

I'm trying to capture the screen to a texture with a lower resolution than the screen itself (to render back onto the screen and create a blur/bloom effect), and it doesn't work quite well. I understand mipmaps can be used to do this, but I just can't get the correct sequence of commands to work. My current code: width=1024; height=102...

OpenGL mipmaps cut out?

Is it possible to cut out the last 3 miplevels, so it wont use higher miplevels than max-3 ? I have problems with high miplevels, they look really bad no matter how much i pad my textures. ...

GPU Manual Mipmap Generation [OpenGL 2.x]

i want use a specific customized algorithm to generate mipmaps for some renderable textures (R16F & RGBA16F). All needed textures' mipmaps are pre-enabled by using glGenerateMipmapEXT(). The biggest problem so far is to render into 1+ mipmap levels. More precisely, this works like a charm: ... glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT); g...

How to map multiple images on a sphere in openGL?

I am able to map a single image as a texture onto the entire surface of a sphere. But when I try to map the image to a small part of the sphere by using mipmaps the image quality is very poor. What should I do to improve that? And also how do I set texture coordinates for the image on the sphere? Is there an option other than mipmaps? ...

OpenGL billboard interpolation issue

I have a billboard quad with a texture mapped onto it. This is basically some text with transparency. The billboard floats forwards and backwards from the camera's perspective. As the billboard moves away (and appears smaller) there is an flickering effect around the edges of the text where there is a stroke border on the actual textu...

OpenGL Mipmapping: how does OpenGL decide on map level?

Hi, I am having trouble implementing mipmapping in OpenGL. I am using OpenFrameworks and have modified the ofTexture class to support the creation and rendering of mipmaps. The following code is the original texture creation code from the class (slightly modified for clarity): glEnable(texData.textureTarget); glBindTexture(t...

How to check for mip-map availability in OpenGL?

Recently I bumped into a problem where my OpenGL program would not render textures correctly on a 2-year-old Lenovo laptop with an nVidia Quadro 140 card. It runs OpenGL 2.1.2, and GLSL 1.20, but when I turned on mip-mapping, the whole screen is black, with no warnings or errors. This is my texture filter code: glTexParameteri(GL_TEXTU...

Blurring the depth buffer in OpenGL - how to access mipmap levels in a fragment shader?

I'm trying to blur a depth texture by blurring & blending mipmap levels in a fragment shader. I have two frambuffer objects: 1) A color frambuffer with a depth renderobject attached. 2) A z framebuffer with a depth texture attached. Once I render the scene to the color framebuffer object, I then blit to the depth buffer object, and ca...

GL: Autogenerating some, but not all, mipmap levels?

I have a texture that I'd like to have relatively fine control over for the two or three largest mipmap levels, but at smaller sizes, I'm happy to have GL generate the mipmaps for me based on the smallest one that I've uploaded, on down to 1x1. Is this possible? FWIW, I'm on iPhone OS with GL ES 1.1 with this. I've tried to enable GL_GE...

Creating and using my own mipmap of a texture atlas

I'm currently using the automatic mipmap generation (C# + OpenTK): GL.GenerateMipmap(GenerateMipmapTarget.Texture2D); The texture I'm using is tiled into blocks of 16px². So my questions would be: Is it possible to use a mipmap which doesn't get downsized to 1x1? What would be the best way to create a mipmap which doesn't "blur" the...

In a GLSL fragment shader, how to access to texel at a specific mipmap level?

Hi, I am using OpenGL to do some GPGPU computations through the combination of one vertex shader and one fragment shader. I need to do computations on a image at different scale. I would like to use mipmaps since their generation can be automatic and hardware accelerated. However I can't manage to get access to the mipmap textures in th...

How to copy CUDA generated PBO to Texture with Mipmapping

I'm trying to copy a PBO into a Texture with automipmapping enabled, but it seems only the top level texture is generated (in other words, no mipmapping is occuring). I'm building a PBO using //Generate a buffer ID called a PBO (Pixel Buffer Object) glGenBuffers(1, pbo); //Make this the current UNPACK buffer glBindBuffer(GL_PIXEL_UNPA...

Is it possible to use custom mipmap sizes?

Hi everybody, i am currently working on some kind of virtual texture implementation. The mipmap levels are used as a level of detail controlling structure. (Every texel in the virtual texture relates to a block of data in the 'real' texture.) The data exists in several detail levels which result in different block counts in the virtual...

OpenGL: Accurate textures possible?

This is for a 2D game with OpenGL: Is it with using OpenGL possible to display a texture absolutely unfiltered, not streched or blurred? So that when I have a BMP and convert it into an OpenGL texture, and then retrieve that texture and convert it back, I have no modifications or quality / data loss? ...

D3D Failed to generate mipmap automatically on some cards!

On most of computers my program performs fine. But on one computer it failed to generate mipmap. I created a texture with D3DUSAGE_AUTOGENERATEMIPMAP, D3DCAPS2_CANAUTOGENMIPMAP says yes and CheckDeviceFormat says D3D_OK(not D3DOK_NOAUTOGEN) too. then I use LoadSurfaceFromMemory to fill the texture. But on that particular computer, ...

trying to run my routine program using a C++ pseudocode.

Program: Ones counter The user will type in an integer. The program will pass the integer to a function that will count the number of binary bits that are "1". Now here is the C+ pseudocode I'm using to translate to MIPS language but when I tried to use it in my program it won't run. I'm I using the right C+...