Hey guys,
I'm trying to render a cube with a 3D texture on it and have trouble when the texturesize becomes to big. I tried a few things to figure out where the texture will be ok or not.
1) First: i figure out which maximum texture size is supported and which version of opengl i'm using.
int texSize[3];
glGetIntegerv(GL_MAX_3D_TEXTURE_SIZE, texSize);
const GLubyte* string = glGetString(GL_VERSION);
The results are: <512, uninitialized, uninitialized> for texSize
and 2.0.1 for string. I assume that this means that the maximum size is <512, 512, 512>
2) Second: i use a proxy texture to find out whether there is enough space for the texture or not
glTexImage3D(GL_PROXY_TEXTURE_3D, 0, GL_RGBA,
extent[0], extent[1], extent[2],
0, GL_LUMINANCE, GL_UNSIGNED_BYTE, 0);
GLint width, height, depth;
glGetTexLevelParameteriv(GL_PROXY_TEXTURE_3D, 0, GL_TEXTURE_WIDTH, &width);
glGetTexLevelParameteriv(GL_PROXY_TEXTURE_3D, 0, GL_TEXTURE_HEIGHT, &height);
glGetTexLevelParameteriv(GL_PROXY_TEXTURE_3D, 0, GL_TEXTURE_DEPTH, &depth);
The extent i'm using is <512, 512, 267>. The width height and depth values are set according to the extent. After that i thought: Well looks good for my texture to fit into memory.
3) Third: Now i'm using Texture Objects to Bind the Texture with the following code
glBindTexture(GL_TEXTURE_3D, identifiers[textureId]);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// extent[0], extent[1], extent[2],
glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA,
extent[0], extent[1], extent[2],
0, GL_LUMINANCE, GL_UNSIGNED_BYTE, image);
delete[] image;
glEnable(GL_TEXTURE_3D);//*/
4) Fourth: I would like to check whether the texture is now ready to use or not, and did the following:
glBindTexture(GL_TEXTURE_3D, identifiers[textureId]);
GLint residency;
glGetTexParameteriv(GL_TEXTURE_3D, GL_TEXTURE_RESIDENT, &residency);
glGetTexLevelParameteriv(GL_TEXTURE_3D, 0, GL_TEXTURE_WIDTH, &width);
glGetTexLevelParameteriv(GL_TEXTURE_3D, 0, GL_TEXTURE_HEIGHT, &height);
glGetTexLevelParameteriv(GL_TEXTURE_3D, 0, GL_TEXTURE_DEPTH, &depth);
Cause' the width, height and depth values are still equal to the extent and not 0 i thought everything is ok.
So whats the problem now: When i use glTexImage3D with my extent than the window is black. When i call it like this:
glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA, extent[0], extent[1], 220, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, image);
everything is ok. When i call it with 230 the window is black. So how can i find out why the window is black. Is it because the texture is to big? But why is glGetTexLevelParameteriv still returning non-zero values?
looking forward to your help!!!
myke
