VBO：数组未绘制 [英] VBO: Array not drawn

问题描述

我关注本指南，我想尝试将四边形绘制到屏幕。我也看到源代码，它是相同的，它应该工作，但在我的情况下没有什么显示在屏幕上。我使用OpenGL 2.0与顶点着色器，只是将颜色设置为红色的四边形应该在屏幕上可见。

I'm following this guide and I'm trying to draw a quad to the screen. I also saw the source code, it's the same and it should work, but in my case nothing is displayed on the screen. I'm using OpenGL 2.0 with a vertex shader that just sets the color to be red in a way that the quad should be visible on the screen.

在callig glutMainLoop之前，我生成顶点缓冲对象：

Before callig glutMainLoop I generate the vertex buffer object:

#include <GL/glut.h>
#include <GL/glew.h>

vector<GLfloat> quad; 
GLuint buffer;

void init()
{
    // This routine gets called before glutMainLoop(), I omitted all the code
    // that has to do with shaders, since it's correct.
    glewInit();
    quad= vector<GLfloat>{-1,-1,0, 1,-1,0, 1,1,0, -1,1,0};
    glGenBuffers(1,&buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER,sizeof(GLfloat)*12,quad.data(),GL_STATIC_DRAW);
}

这是我的呈现程序：

void display()
{
    glClearColor(0,0,0,0);
    glClear(GL_COLOR_BUFFER_BIT);

    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER,buffer);
    glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,0);
    // I also tried passing quad.data() as last argument, but nothing to do.
    glDrawArrays(GL_QUADS,0,12);
    glDisableVertexAttribArray(0);

    glutSwapBuffers();
}

问题是没有什么东西画到屏幕上，我只是看到一个黑色窗口。

The problem is that nothing is drawn to the screen, I just see a black window. The quad should be red because I set the red color in the vertex shader.

推荐答案

我失去了glEnableClientState，像这样：

I was missing glEnableClientState like this:

glEnableClientState(GL_VERTEX_ARRAY);
glDrawArrays(GL_QUADS,0,12);
glDisableClientState(GL_VERTEX_ARRAY);

这篇关于VBO：数组未绘制的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！