python下学习opengl之着色器

Posted 2020-11-01 wndf6122

https://learnopengl.com/Getting-started/Shaders在vertex着色器中增加了三角形顶点的颜色属性, 该章节的中文翻译版见中文教程

对应的python代码如下：

  1 #! /usr/bin/env python
  2 # -*- coding: utf-8 -*-
  3 
  4 import sys, os
  5 import OpenGL.GL as gl
  6 import glfw
  7 import numpy as np
  8 from ctypes import c_void_p
  9 
 10 WIN_WIDTH = 800
 11 WIN_HEIGHT = 600
 12 
 13 vertexShaderSource = """
 14 #version 330 core
 15 layout (location = 0) in vec3 aPos;
 16 layout (location = 1) in vec3 aColor;
 17 out vec3 ourColor;
 18 void main()
 19 {
 20     gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
 21     ourColor = aColor;
 22 }
 23 """
 24 
 25 fragmentShaderSource = """
 26 #version 330 core
 27 out vec4 FragColor;
 28 in vec3 ourColor;
 29 void main()
 30 {
 31     FragColor = vec4(ourColor, 1.0);
 32 }
 33 """
 34 vertices = np.array([0.5,-0.5, 0, 1.0, 0, 0,
 35                     -0.5,-0.5, 0, 0, 1.0, 0,
 36                      0.0, 0.5, 0, 0, 0, 1.0], dtype = np.float32)
 37 
 38 
 39 def framebuffer_size_callback(window, width, height):
 40     gl.glViewport(0, 0, width, height)
 41 
 42 def processInput(window):
 43     if glfw.glfwGetKey(window, glfw.GLFW_KEY_ESCAPE) == glfw.GLFW_PRESS:
 44         glfw.glfwSetWindowShouldClose()
 45 
 46     if glfw.glfwGetKey(window, glfw.GLFW_KEY_LEFT) == glfw.GLFW_PRESS:
 47         gl.glPolygonMode(gl.GL_FRONT_AND_BACK, gl.GL_FILL)
 48 
 49     if glfw.glfwGetKey(window, glfw.GLFW_KEY_RIGHT) == glfw.GLFW_PRESS:
 50         gl.glPolygonMode(gl.GL_FRONT_AND_BACK, gl.GL_LINE)
 51 
 52 def main():
 53     glfw.glfwInit()
 54     glfw.glfwWindowHint(glfw.GLFW_CONTEXT_VERSION_MAJOR, 3)
 55     glfw.glfwWindowHint(glfw.GLFW_CONTEXT_VERSION_MINOR, 3)
 56     glfw.glfwWindowHint(glfw.GLFW_OPENGL_PROFILE, glfw.GLFW_OPENGL_CORE_PROFILE)
 57 
 58     window = glfw.glfwCreateWindow(WIN_WIDTH, WIN_HEIGHT, "学习OpenGL".encode(), 0, 0)
 59     if window == 0:
 60         print("failed to create window")
 61         glfw.glfwTerminate()
 62 
 63     glfw.glfwMakeContextCurrent(window)
 64     glfw.glfwSetFramebufferSizeCallback(window, framebuffer_size_callback)
 65 
 66     vertexShader = gl.glCreateShader(gl.GL_VERTEX_SHADER)
 67     gl.glShaderSource(vertexShader, vertexShaderSource)
 68     gl.glCompileShader(vertexShader)
 69 
 70     fragmentShader = gl.glCreateShader(gl.GL_FRAGMENT_SHADER)
 71     gl.glShaderSource(fragmentShader, fragmentShaderSource)
 72     gl.glCompileShader(fragmentShader)
 73 
 74     shaderProgram = gl.glCreateProgram()
 75     gl.glAttachShader(shaderProgram, vertexShader)
 76     gl.glAttachShader(shaderProgram, fragmentShader)
 77     gl.glLinkProgram(shaderProgram)
 78 
 79     gl.glDeleteShader(vertexShader)
 80     gl.glDeleteShader(fragmentShader)
 81 
 82     VAO = gl.glGenVertexArrays(1)
 83     VBO, EBO = gl.glGenBuffers(2)
 84 
 85     gl.glBindVertexArray(VAO)
 86     gl.glBindBuffer(gl.GL_ARRAY_BUFFER, VBO)
 87     gl.glBufferData(gl.GL_ARRAY_BUFFER, sys.getsizeof(vertices), vertices, gl.GL_STATIC_DRAW)
 88 
 89     gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 24, c_void_p(0))
 90     gl.glEnableVertexAttribArray(0)
 91     gl.glVertexAttribPointer(1, 3, gl.GL_FLOAT, gl.GL_FALSE, 24, c_void_p(12))
 92     gl.glEnableVertexAttribArray(1)
 93     gl.glBindBuffer(gl.GL_ARRAY_BUFFER, 0)
 94     gl.glBindVertexArray(0)
 95 
 96     while not glfw.glfwWindowShouldClose(window):
 97         processInput(window)
 98         gl.glClearColor(0.2, 0.3, 0.3, 1.0)
 99         gl.glClear(gl.GL_COLOR_BUFFER_BIT)
100 
101         gl.glUseProgram(shaderProgram)
102 
103         gl.glBindVertexArray(VAO)
104         gl.glDrawArrays(gl.GL_TRIANGLES, 0, 3)
105 
106         glfw.glfwSwapBuffers(window)
107         glfw.glfwPollEvents()
108 
109     glfw.glfwTerminate()
110 
111 if __name__ == "__main__":
112     main()

代码执行效果：