texture-mapping

问题 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_UNPACK_BUFFER, *pbo); //Allocate data for the buffer. 4-channel 8-bit image glBufferData(GL_PIXEL_UNPACK_BUFFER, size_tex_data, NULL, GL_DYNAMIC_COPY);

问题 Anyone happen to know why I'm getting a segmentation fault at line 2 below (this is after all my glInit stuff)? I've tried different image formats (.jpeg, .png, .bmp, all from internet). Debug tips or anything helps! If you wanna see more source, ask and I'll edit promptly. ilutRenderer(ILUT_OPENGL); GLuint tex1 = ilutGLLoadImage("/home/brent/Desktop/myimage.jpeg"); gdb backtrace, for what it's worth: #0 0x00000000 in ?? () #1 0x021b318e in ilDetermineType ( FileName=0x804ad84 "/home/brent

问题 i am using a ppm loader to set image as a background , but there is a problem in colors here is the code and the image that i am use . http://imgur.com/w732d6j http://imgur.com/mJr26Ik here is the code ..... texture.h #ifndef TEXTURE_H #define TEXTURE_H struct Image { unsigned char* pixels; int width; int height; int numChannels; }; class Texture { public: Texture (); void Prepare (int texN); void ReadPPMImage (char *fn); GLuint texName; Image image; }; #endif texture.cpp #include <fstream>

问题 I just have started with Python and I would translate this example from MATLAB to Python, but I have not found the equivalent in Python. https://www.mathworks.com/help/matlab/ref/surface.html load clown surface(peaks,flipud(X),... 'FaceColor','texturemap',... 'EdgeColor','none',... 'CDataMapping','direct') colormap(map) view(-35,45) Thanks! 回答1: Matplotlib offers nearly all plotting options Matlab does. Surface plots can be done as well: http://matplotlib.org/mpl_toolkits/mplot3d/tutorial

问题 I am drawing a 3d sphere using GL_QUAD_STRIP primitive and it works except I don't know how to set up the texture coordinates. I have a certain number of division that divide my sphere into equal number of latitudes and longitudes. Hence, the sphere's vertices are approximated using the divisions as follows float x, y, z, dTheta=180/divisions, dLon=360/divisions, degToRad=3.14/180 ; for(float lat =0 ; lat <=180 ; lat+=dTheta) { glBegin( GL_QUAD_STRIP ) ; for(float lon = 0 ; lon <=360; lon+

问题 I've been wondering is it possible to do skinning to the 3d text with loaded images as texture? I knew you could do it with cubes and others since most of the sample were showing tutorials how to do it. What did I tried was map it with THREE. ImageUtils.loadTexture directed from the path but what did i get is some transparency object. I wonder how to use the same concept such as: CubeGeometry(width, height, depth, widthSegments, heightSegments, depthSegments, listofmaterials) in TextGeometry

问题 I'm not sure how to go about figuring out how to map texture cooridnates for a 2D NGon (N sided polygon) How can this be done? The effect i'm trying to achieve is for the texture to fit on the polygon and stretch out accordingly so the whole texture fits on it. Thanks 回答1: Remember that when rendering an ngon in OpenGL, it's just a whole bunch of triangles. Also, you're taking some shape and trying to map it to a rectangle, so you have to be extremely critical of how you wish to do this as

问题 I'm making a object loader, and all the texture parts are in different texture files. What is the best solution of having it mapped on the model? Do I need to treat every part that has it's own texture as 1 model, so that the final body has many separate drawing calls with one texture each? 回答1: With the advent of the programmable rendering pipeline (i.e.: shaders ) you can now apply and combine multiple textures to meshes without the need for multiple draw calls. Modern GPUs have several

问题 I have a cube map texture in OpenGL, and I'd like to render one face of the cube to a single quad. What texture coordinates should I use? To be concrete, what coordinates should I pick to render the "GL_TEXTURE_CUBE_MAP_POSITIVE_X" face? Or if I shouldn't explicitly define coordinates, how should I use texture coordinate generation in this instance? 回答1: The texture coordinates you want are (1, +/-1, +/-1) 来源： https://stackoverflow.com/questions/8565093/render-face-of-cube-map-to-a-quad

问题 I am having buggy texture map on my sphere. The issue is well known but solution is rare. This is my code for generating UVs for a sphere. T = triangles, Nv = vertex normals. for (int i=0; i<nbF; i++) { float tx1 = atan2(Nv[T[i].v1].x, Nv[T[i].v1].z) / (2.0f*M_PI) + 0.5f; float ty1 = asinf(Nv[T[i].v1].y) / M_PI + 0.5f; float tx2 = atan2(Nv[T[i].v2].x, Nv[T[i].v2].z) / (2.0f*M_PI) + 0.5f; float ty2 = asinf(Nv[T[i].v2].y) / M_PI + 0.5f; float tx3 = atan2(Nv[T[i].v3].x, Nv[T[i].v3].z) / (2.0f*M