vbo | 易学教程

How can I make OpenGL draw something using VBOs in XCODE?

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问题 Good evening, Right now I'm trying to run the following code using Xcode, but it has been impossible so far. The code is a from a simple tutorial I found online, and the code is supposed to simply draw a triangle using OpenGL and VBOs. If I try the code using Visual Studio, I actually get the expected result with no problems at all. However, when I try to run the code using Xcode, I only get a black screen. To setup the project in Xcode, I installed GLEW and FreeGlut using MacPorts and then I

What are Vertex Array Objects?

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I am just starting to learn OpenGL today from this tutorial: http://openglbook.com/the-book/ I got to chapter 2, where I draw a triangle, and I understand everything except VAOs (is this acronym OK?). The tutorial has this code: glGenVertexArrays(1, &VaoId); glBindVertexArray(VaoId); While I understand that the code is necessary, I have no clue what it does. Although I never use VaoId past this point (except to destroy it), the code does not function without it. I am assuming this is because it is required to be bound, but I don't know why. Does this exact code just need to be part of every

understanding glVertexAttribPointer?

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问题 i am a newbie at Open GL and came here to clear out a confusion i had. I appreciate any help! private int vbo; private int ibo; vbo = glGenBuffers(); ibo = glGenBuffers(); glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, Util.createFlippedBuffer(vertices), GL_STATIC_DRAW); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo); glBufferData(GL_ELEMENT_ARRAY_BUFFER, Util.createFlippedBuffer(indices), GL_STATIC_DRAW); glEnableVertexAttribArray(0); glEnableVertexAttribArray(1); /

The best way to use VBOs [closed]

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问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 6 years ago . What are the fastest and the most flexible (applicable in most situations) ways to use VBOs? I am developing an openGL application and

When are VBOs faster than “simple” OpenGL primitives (glBegin())?

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问题 After many years of hearing about Vertex Buffer Objects (VBOs), I finally decided to experiment with them (my stuff isn't normally performance critical, obviously...) I'll describe my experiment below, but to make a long story short, I'm seeing indistinguishable performance between "simple" direct mode (glBegin()/glEnd()), vertex array (CPU side) and VBO (GPU side) rendering modes. I'm trying to understand why this is, and under what conditions I can expect to see the VBOs significantly

Use of Vertex Array Objects and Vertex Buffer Objects

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问题 I am trying to understand these two, how to use them and how they are related. Let's say I want to create a simple terrain and a textured cube. For both objects I have the array of triangles vertices and for the cube I have an array containing the texture's data. My question is: how do I use VAOs and VBOs to create and render these two? Would I have to create a VAO and VBO for each object? or should create a VAO for each object's VBO (vertices, texture data, etc.)? There are many tutorials

How can I optimize the rendering of a large model in OpenGL ES 1.1?

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I just finished implementing VBO's in my 3D app and saw a roughly 5-10x speed increase in rendering. What used to render at 1-2 frames per second now renders at 10-11 frames per second. My question is, are there any further improvements I can make to increase rendering speed? Will triangle strips make a big difference? Currently vertices are not being shared between faces, each faces vertices are unique but overlapping. My Device Utilization is 100%, Tiler Utilization is 100%, Renderer Utilization is 11%, and resource bytes is 114819072. This is rendering 912,120 faces on a CAD model. Any

VBOs with std::vector

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I've written a model loader in C++ an OpenGL. I've used std::vector s to store my vertex data, but now I want to pass it to glBufferData() , however the data types are wildly different. I want to know if there's a way to convert between std::vector to the documented const GLvoid * for glBufferData() . Vertex type typedef struct { float x, y, z; float nx, ny, nz; float u, v; } Vertex; vector<Vertex> vertices; glBufferData() call glBufferData(GL_ARRAY_BUFFER, vertices.size() * 3 * sizeof(float), vertices, GL_STATIC_DRAW); I get the following (expected) error: error: cannot convert ‘std::vector

How to draw a circle using VBO in ES2.0

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I am trying to develop an ES 2.0 application in Linux environment. My target GPU is Fujitsu ruby MB86298 . To optimize the performance I have decided to use the VBO concept. I am very new to VBOs. I rendered basic primitives like triangle and quads using VBO where I have less no vertices . For rendering crown using a VBO, I computed all the vertices(more than 200). Now I am finding difficulty in sending this data of 200 vertices to the VBO.I cannot manually enter the all the vertex data and store in an array and pass it to VBO. Is there any way to send that vertex data of each for loop( used

What are Vertex Array Objects?

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问题 I am just starting to learn OpenGL today from this tutorial: http://openglbook.com/the-book/ I got to chapter 2, where I draw a triangle, and I understand everything except VAOs (is this acronym OK?). The tutorial has this code: glGenVertexArrays(1, &VaoId); glBindVertexArray(VaoId); While I understand that the code is necessary, I have no clue what it does. Although I never use VaoId past this point (except to destroy it), the code does not function without it. I am assuming this is because