我知道在2.0版本的OpenGL中,我们可以很简单地画一条直线,就像这样:
glBegin(GL_LINES);
glBegin(GL_LINES);
glVertex3f(20.0f,150.0f,0.0f);
glVertex3f(220.0f,150.0f,0.0f);
glVertex3f(200.0f,160.0f,0.0f);
glVertex3f(200.0f,160.0f,0.0f);
glEnd();
但是如何在现代OpenGL(3.0+)中做类似的事情呢?
我阅读了使用现代OpenGL绘制圆形点,但答案并不是关于特定点的,因为我想用具有特定坐标的点来绘制多边形,它并不是很有帮助。
我使用了这段代码,但除了一个蓝色背景外,什么也没有显示。我错过了什么吗?
GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);
static const GLfloat g_vertex_buffer_data[] = {
20.0f, 150.0f, 0.0f, 1.0f,
220.0f, 150.0f, 0.0f, 1.0f,
200.0f, 160.0f, 0.0f, 1.0f
};
GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
do{
// Clear the screen
glClear( GL_COLOR_BUFFER_BIT );
// 1rst attribute buffer : vertices
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glVertexAttribPointer(
0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
4, // size
GL_FLOAT, // type
GL_FALSE, // normalized?
0, // stride
(void*)0 // array buffer offset
);
// Draw the triangle !
glDrawArrays(GL_LINES, 0, 2); // 3 indices starting at 0 -> 1 triangle
glDisableVertexAttribArray(0);
// Swap buffers
glfwSwapBuffers(window);
} // Check if the ESC key was pressed or the window was closed
while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
glfwWindowShouldClose(window) == 0 );