OpenGL笔记五之VBO与VAO

OpenGL笔记五之VBO与VAO

总结自bilibili赵新政老师的教程

code review!

1.VBO

代码

void prepareVBO() {
//1 创建一个vbo  *******还没有真正分配显存*********
GLuint vbo = 0;
GL_CALL(glGenBuffers(1, &vbo));

//2 销毁一个vbo
GL_CALL(glDeleteBuffers(1, &vbo));

//3 创建n个vbo
GLuint vboArr[] = {0, 0, 0};
GL_CALL(glGenBuffers(3, vboArr));

//4 销毁n个vbo
GL_CALL(glDeleteBuffers(3, vboArr));
}

void prepare() {
float vertices[] = {
   -0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f,  0.5f, 0.0f
};

//1 生成一个vbo
GLuint vbo = 0;
GL_CALL(glGenBuffers(1, &vbo));

//2 绑定当前vbo，到opengl状态机的当前vbo插槽上
//GL_ARRAY_BUFFER:表示当前vbo这个插槽
GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, vbo));

//3 向当前vbo传输数据，也是在开辟显存
GL_CALL(glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW));
}

void prepareSingleBuffer() {
//1 准备顶点位置数据与颜色数据
float positions[] = {
   -0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f,  0.5f, 0.0f
};
float colors[] = {
   1.0f, 0.0f, 0.0f,
   0.0f, 1.0f, 0.0f,
   0.0f,  0.0f, 1.0f
};

//2 为位置&颜色数据各自生成一个vbo
GLuint posVbo = 0, colorVbo = 0;
GL_CALL(glGenBuffers(1, &posVbo));
GL_CALL(glGenBuffers(1, &colorVbo));

//3 给两个分开的vbo各自填充数据
//position填充数据
GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, posVbo));
GL_CALL(glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW));

//color填充数据
GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, colorVbo));
GL_CALL(glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW));
}

void prepareInterleavedBuffer() {
float vertices[] = {
   -0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
0.0f,  0.5f, 0.0f, 0.0f, 0.0f, 1.0f
};

GLuint vbo = 0;
GL_CALL(glGenBuffers(1, &vbo));

GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, vbo));

GL_CALL(glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW));

}

2.VAO

代码

void prepareSingleBuffer() {
//1 准备positions colors数据
float positions[] = {
   -0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f,  0.5f, 0.0f
};
float colors[] = {
   1.0f, 0.0f, 0.0f,
   0.0f, 1.0f, 0.0f,
   0.0f,  0.0f, 1.0f
};


//2 使用数据生成两个vbo posVbo， colorVbo
GLuint posVbo, colorVbo;
glGenBuffers(1, &posVbo);
glGenBuffers(1, &colorVbo);

glBindBuffer(GL_ARRAY_BUFFER, posVbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(positions), positions, GL_STATIC_DRAW);

glBindBuffer(GL_ARRAY_BUFFER, colorVbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);

//3 生成vao并且绑定
GLuint vao = 0;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);

//4 分别将位置/颜色属性的描述信息加入vao当中
//4.1描述位置属性
glBindBuffer(GL_ARRAY_BUFFER, posVbo);//只有绑定了posVbo，下面的属性描述才会与此vbo相关
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);

//4.2 描述颜色属性
glBindBuffer(GL_ARRAY_BUFFER, colorVbo);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);

glBindVertexArray(0);
}


void prepareInterleavedBuffer() {
//1 准备好Interleaved数据（位置+颜色）
float vertices[] = {
   -0.5f, -0.5f, 0.0f,  1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.0f,  0.0f, 1.0f, 0.0f,
0.0f,  0.5f, 0.0f,  0.0f,  0.0f, 1.0f
};


//2 创建唯一的vbo
GLuint vbo = 0;
GL_CALL(glGenBuffers(1, &vbo));
GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, vbo));
GL_CALL(glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW));

//3 创建并绑定vao
GLuint vao = 0;
GL_CALL(glGenVertexArrays(1, &vao));
GL_CALL(glBindVertexArray(vao));


GL_CALL(glBindBuffer(GL_ARRAY_BUFFER, vbo));
//4 为vao加入位置和颜色的描述信息
//4.1 位置描述信息
GL_CALL(glEnableVertexAttribArray(0));
GL_CALL(glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0));

//4.2 颜色描述信息
GL_CALL(glEnableVertexAttribArray(1));
GL_CALL(glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float))));

//5 扫尾工作：解绑当前vao
glBindVertexArray(0);
}

3.VBO与VAO对比

原文地址：https://blog.csdn.net/weixin_43297891/article/details/140388774

免责声明：本站文章内容转载自网络资源，如本站内容侵犯了原著者的合法权益，可联系本站删除。更多内容请关注自学内容网（zxcms.com）！