vao

问题 So I'm swapping from one program to another, and I can't figure out why but GL_QUADS will no longer display with the same code. To try and figure out why old code was not working, I made this new, simple code and it STILL does not work. The setup: vector <vec3f> squarepoints; vec3f temper(-0.5f, 0.5f, 0.5f); squarepoints.push_back(temper); temper.x += 1.0f; squarepoints.push_back(temper); temper.y -= 1.0f; squarepoints.push_back(temper); temper.x -= 1.0f; squarepoints.push_back(temper);

问题 All, Having difficulty with glGenVertexArrays(). I get the following error: Exception in thread "main" java.lang.IllegalStateException: This functionality is not available. at org.lwjgl.system.Checks.checkFunctionality(Checks.java:57) at org.lwjgl.opengl.GL30.getInstance(GL30.java:667) at org.lwjgl.opengl.GL30.getInstance(GL30.java:662) at org.lwjgl.opengl.GL30.nglGenVertexArrays(GL30.java:2789) at org.lwjgl.opengl.GL30.glGenVertexArrays(GL30.java:2816) at renderEngine.Loader.createVAO(Loader

问题 I'm trying to render multiple objects in OpenGL using multiple VAO's and VBO's. To render multiple objects using the same vertices I've done it, but what I want to do is to use different vertices for each object, for example to draw a square and a circle. For a square I only need 6 vertices but for circle I need 360. I have error with reading or creating the shaders. Here is the Vertex Shader: #version 330 core layout (location = 0) in vec4 position; uniform mat4 model; uniform mat4 view;

问题 I'm working on OpenGL program and I must calculate a bounding box . I made the code to do it but I can't get vertexes coordinations from vertex buffer . Someone can explain me an easy way to get data from vertex buffer? I'm using Java for android and OpenGL es 回答1: If you use OpenGL ES 3.0 or later, you can use glMapBufferRange() to access buffer data directly. See the man page for details about the functionality, and the GLES30 documentation for details about the Java bindings in Android. I

问题 I am writing an OpenGL3+ application and have some confusion about the use of VAOs. Right now I just have one VAO, a normalised quad set around the origin. This single VAO contains 3 VBOs; one for positions, one for surface normals, and one GL_ELEMENT_ARRAY_BUFFER for indexing (so I can store just 4 vertices, rather than 6). I have set up some helper methods to draw objects to the scene, such as drawCube() which takes position and rotation values and follows the procedure; Bind the quad VAO.

问题 #define GLEW_STATIC #include <GL\glew.h> #include <GLFW\glfw3.h> #include <GL\glew.h> #include <glm.hpp> #include <iostream> #include <fstream> #include <string> #define WIDTH 800 #define HEIGHT 600 #define TITLE "Dynamic" GLFWwindow* window; int vaoID; float vertices[] = {-0.5f, 0.5f, 0, -0.5f, -0.5f, 0, 0.5f, 0.5f, 0, 0.5f, 0.5f, 0, -0.5f, -0.5f, 0, 0.5f, -0.5f, 0}; void loadToVAO(float vertices[]); void update() { loadToVAO(vertices); while (!glfwWindowShouldClose(window)) { glfwPollEvents

问题 This question already has answers here : What is the purpose of `glEnableVertexAttribArray(GLuint index)` in OpenGL? (2 answers) Closed 3 years ago . Using glVertexAttribPointer the opengl implementation already knows to which attribute location/index in vertex shader Vertex Attribute Object is bound, so why is there the need to provide attribute index in glEnableVertexAttribArray again? I think after using glBindVertexArray(VAO); it could have been enough to use just

问题 I need to create a grid like this: ---------------- | | | | | | ---------------- | | | | | | ---------------- | | | | | | ---------------- and rendering it just with lines. This is how I create the vertices and the indices: std::vector<glm::vec3> vertices; std::vector<glm::uvec3> indices; for(int j=0; j<=slices; ++j) { for(int i=0; i<=slices; ++i) { float x = (float)i/(float)slices; float y = 0; float z = (float)j/(float)slices; vertices.push_back(glm::vec3(x, y, z)); } } for(int j=0; j

问题 I am trying to draw part of my tile image but I am getting GL_INVALID_VALUE error when I call glDrawElements function. There is no problem when I change this function with glDrawArrays. The problem is that the indices count parameter is not negative number. There is a code: #define BUFFER_OFFSET(i) ((char *)nullptr + (i)) #define VERTEX_ATTR_PTR(loc, count, member, type) \ glEnableVertexAttribArray(loc); \ glVertexAttribPointer(loc, count, GL_FLOAT, GL_FALSE, sizeof(type), BUFFER_OFFSET

问题 Are OpenGL's Vertex Array Objects stored in VRam? What I'm really asking: If I load a model, using Assimp for example, then read the vertex and indice data into Vertex Array Objects; will I be duplicating data in Ram, or copying it to the GPU? 回答1: There seems to be a lack of understanding of OpenGL terminology here. You cannot read "vertex and indice data" into Vertex Array Objects. They don't actually store the data; the arrays of data are stored in buffer objects. VAOs only reference them.