我是 OpenGL 的新手,我正在尝试使用两个 VAO 和一个 VBO 绘制两个三角形。即使经过一些研究,我对 VAO、VBO 以及所需的 glew 函数如何工作有了更好的了解,我仍然不知道为什么我的程序只显示一个三角形而不是两个。有人可以帮忙吗?
...
GLfloat points[] = {
0.5f, 0.5f, 0.0f, //First Triangle
-0.5f, 0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f, 0.0f, 0.0f, //Second Triangle
-1.0f, 0.0f, 0.0f,
0.0f, -1.0f, 0.0f
};
GLuint vbo;
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
GLuint vao1;
glGenVertexArrays(1, &vao1);
glBindVertexArray(vao1);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
GLuint vao2;
glGenVertexArrays(1, &vao2);
glBindVertexArray(vao2);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (char*)NULL + 9);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
...
while (!glfwWindowShouldClose(window))
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(shader_program);
glBindVertexArray(vao1);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
glBindVertexArray(vao2);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
glUseProgram(0);
glfwPollEvents();
glfwSwapBuffers(window);
}
...
最佳答案
此函数调用的最后一个参数不正确:
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (char*)NULL + 9);
你告诉它添加 9 个字节,但你的点是 float
试试这个:
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (char*)NULL + 9 * sizeof(float));
关于c++ - OpenGL : multiple VAOs for one VBO,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38486070/