OpenGL 教程的 Python 端口未绘制任何内容

Question

我终于尝试学习“现代”OpenGL，并且我已经阅读了here的教程，但我正在使用 Python 工作。

在我自己尝试绘制三角形失败（没有渲染任何内容）后，我决定直接将练习 1的 C++ 解决方案移植到 Python。

这就是结果，它与 C++ 代码几乎是 1:1，afaict，除了为了简洁起见，我删除了着色器编译/链接错误检查（

在验证程序正在编译和链接时没有错误）：

from platform import system
import numpy as np
import glfw
from OpenGL.GL import *

SCR_WIDTH = 800
SCR_HEIGHT = 600

vertex_shader_source = """
    #version 330 core
    layout (location = 0) in vec3 aPos;

    void main()
    {
        gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
    }
"""

fragment_shader_source = """
    #version 330 core
    out vec4 FragColor;

    void main()
    {
        FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
    }     
"""

def main ():
    
    # glfw: initialize and configure
    # ------------------------------
    glfw.init()
    glfw.window_hint(glfw.CONTEXT_VERSION_MAJOR, 3)
    glfw.window_hint(glfw.CONTEXT_VERSION_MINOR, 3)
    glfw.window_hint(glfw.OPENGL_PROFILE, glfw.OPENGL_CORE_PROFILE)
    if system() == "Darwin":
        glfw.window_hint(glfw.OPENGL_FORWARD_COMPAT, GL_TRUE)
        
    # glfw window creation
    # --------------------
    window = glfw.create_window(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", None, None)
    glfw.make_context_current(window)
    glfw.set_window_size_callback(window, framebuffer_size_callback)
    
    # build and compile our shader program
    # ------------------------------------
    # vertex shader
    vertex_shader = glCreateShader(GL_VERTEX_SHADER)
    glShaderSource(vertex_shader, vertex_shader_source)
    glCompileShader(vertex_shader)
    # fragment shader
    fragment_shader = glCreateShader(GL_FRAGMENT_SHADER)
    glShaderSource(fragment_shader, fragment_shader_source)
    glCompileShader(fragment_shader)
    # link shaders
    shader_program = glCreateProgram()
    glAttachShader(shader_program, vertex_shader)
    glAttachShader(shader_program, fragment_shader)
    glLinkProgram(shader_program)
    glDeleteShader(vertex_shader)
    glDeleteShader(fragment_shader)
    
    # set up vertex data (and buffer(s)) and configure vertex attributes
    # ------------------------------------------------------------------
    vertices = np.array([
        # first triangle
        -0.9, -0.5, 0.0,  # left 
        -0.0, -0.5, 0.0,  # right
        -0.45, 0.5, 0.0,  # top 
        # second triangle
        0.0, -0.5, 0.0,  # left
        0.9, -0.5, 0.0,  # right
        0.45, 0.5, 0.0   # top 
    ], np.float32)
    
    vao = glGenVertexArrays(1)
    vbo = glGenBuffers(1)
    # bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
    glBindVertexArray(vao)
    
    glBindBuffer(GL_ARRAY_BUFFER, vbo)
    glBufferData(GL_ARRAY_BUFFER, vertices, GL_STATIC_DRAW)
    
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 12, 0)
    glEnableVertexAttribArray(0)
    
    glBindBuffer(GL_ARRAY_BUFFER, 0)
    glBindVertexArray(0)
    
    # render loop
    # -----------
    while not glfw.window_should_close(window):
    
        # render
        # ------
        glClearColor(0.2, 0.3, 0.3, 1.0)
        glClear(GL_COLOR_BUFFER_BIT)
        
        # draw our first triangle
        glUseProgram(shader_program)
        glBindVertexArray(vao)
        glDrawArrays(GL_TRIANGLES, 0, 6)
    
        # glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        # -------------------------------------------------------------------------------
        glfw.swap_buffers(window)
        glfw.poll_events()
        
    # optional: de-allocate all resources once they've outlived their purpose:
    # ------------------------------------------------------------------------
    glDeleteVertexArrays(1, [vao])
    glDeleteBuffers(1, [vbo])
    glDeleteProgram(shader_program)

    # glfw: terminate, clearing all previously allocated GLFW resources.
    # ------------------------------------------------------------------
    glfw.terminate()
    
    
def framebuffer_size_callback (window, width, height):
    glViewport(0, 0, width, height)

   
if __name__ == "__main__":
    main()

不幸的是，它仍然没有渲染任何东西：

我不明白为什么，也不知道该尝试什么。一切似乎都与示例解决方案相匹配。

所以我在让我的着色器实验渲染任何东西方面都是 0 换 2。我在这里缺少什么？

我使用的是 Windows 10，使用 Nvidia Quadro RTX 4000。Python 3.11.1、PyOpenGL 3.1.6。

Answer 1

啊，我明白了。手动尝试了各种小改动后，我发现是这一行：

glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 12, 0) 应该是：

glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 12, None) 也就是说，最后一个参数应该是

None

，而不是

0

。