Python GLM OpenGL

1. 概述

本文基于Python语言，描述OpenGL的变换

前置知识可参考：

• 基于Python的OpenGL 03 之纹理 - 当时明月在曾照彩云归 - 博客园 [cnblogs. com]

笔者这里不过多描述每个名词、函数和细节，更详细的文档可以参考：

• 变换 - LearnOpenGL CN [learnopengl-cn. github. i]

2. 导入GLM

平移、旋转、缩放等变换主要是使用变换矩阵来实现

OpenGL Mathematics[GLM]是一个基于GLSL的只有头文件的C++数学运算库

GLM的GitHub站点为：g-truc/glm. Toán học OpenGL [GLM] [github. com]

PyGLM是GLM的Python绑定，其API基本一致

PyGLM的GitHub站点为：Zuzu-Typ/PyGLM. Toán học OpenGL nhanh [GLM] cho Python [github. com]

PyGLM的PyPi地址为：PyGLM · PyPI

使用pip安装PyGLM：

pip install PyGLM

引入GLM：

import glm

3. 设置变换矩阵

设置一个平移、旋转、缩放的矩阵：

trans = glm.mat4[1.0]
trans = glm.translate[trans, glm.vec3[0.5, -0.5, 0.0]*np.sin[glfw.get_time[]]]
trans = glm.rotate[trans, glfw.get_time[], glm.vec3[0.0, 0.0, 1.0]]
trans = glm.scale[trans, glm.vec3[1.0, 1.0, 0.0]*[np.sin[glfw.get_time[]]*0.5+0.5]]

在顶点着色器中将变换矩阵与坐标结合：

#version 330 core
layout [location = 0] in vec3 aPos;
layout [location = 1] in vec3 aColor;
layout [location = 2] in vec2 aTexCoord;

out vec3 ourColor;
out vec2 TexCoord;

uniform mat4 transform;

void main[]
{
    gl_Position = transform * vec4[aPos, 1.0];
    ourColor = aColor;
    TexCoord = aTexCoord;
}

将变换矩阵输入到GPU：

glUniformMatrix4fv[glGetUniformLocation[shader.shaderProgram, 'transform'], 1, GL_FALSE, glm.value_ptr[trans]]

如果顺利的话，结果如下：

4. 完整代码

主要文件

import glm

import glfw as glfw
from OpenGL.GL import *
import numpy as np
from PIL.Image import open
import glm as glm

import shader as shader

glfw.init[]
window = glfw.create_window[800, 600, "transformation", None, None]
glfw.make_context_current[window]

VAO = glGenVertexArrays[1]
glBindVertexArray[VAO]

vertices = np.array[[
     # ---- 位置 ----       ---- 颜色 ----     - 纹理坐标 -
     0.5,  0.5, 0.0,   1.0, 0.0, 0.0,   1.0, 1.0,   # 右上
     0.5, -0.5, 0.0,   0.0, 1.0, 0.0,   1.0, 0.0,   # 右下
    -0.5, -0.5, 0.0,   0.0, 0.0, 1.0,   0.0, 0.0,   # 左下
    -0.5,  0.5, 0.0,   1.0, 1.0, 0.0,   0.0, 1.0,   # 左上
                    ]]
VBO = glGenBuffers[1]
glBindBuffer[GL_ARRAY_BUFFER, VBO]
glBufferData[GL_ARRAY_BUFFER, 8 * vertices.size, vertices, GL_STATIC_DRAW]
glVertexAttribPointer[0, 3, GL_DOUBLE, GL_FALSE, int[8 * 8], None]
glEnableVertexArrayAttrib[VAO, 0]
glVertexAttribPointer[1, 3, GL_DOUBLE, GL_FALSE, int[8 * 8], ctypes.c_void_p[8 * 3]]
glEnableVertexArrayAttrib[VAO, 1]
glVertexAttribPointer[2, 2, GL_DOUBLE, GL_FALSE, int[8 * 8], ctypes.c_void_p[8 * 6]]
glEnableVertexAttribArray[2]

indices = np.array[[
        0, 1, 3,  # first triangle
        1, 2, 3  # second triangle
        ]]
EBO = glGenBuffers[1]
glBindBuffer[GL_ELEMENT_ARRAY_BUFFER, EBO]
glBufferData[GL_ELEMENT_ARRAY_BUFFER, 8 * indices.size, indices, GL_STATIC_DRAW]

image = open['./textures/container.jpg']
texture = glGenTextures[1]
glBindTexture[GL_TEXTURE_2D, texture]
# 为当前绑定的纹理对象设置环绕、过滤方式
glTexParameteri[GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT]
glTexParameteri[GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT]
glTexParameteri[GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR]
glTexParameteri[GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR]
glTexImage2D[GL_TEXTURE_2D, 0, GL_RGB, image.size[0], image.size[1], 0, GL_RGB, GL_UNSIGNED_BYTE, image.tobytes[]]
glGenerateMipmap[GL_TEXTURE_2D]

shader = shader.Shader["./glsl/test.vs.glsl", "./glsl/test.fs.glsl"]

while not glfw.window_should_close[window]:
    glClearColor[0.2, 0.3, 0.3, 1.0]
    glClear[GL_COLOR_BUFFER_BIT]

    trans = glm.mat4[1.0]
    trans = glm.translate[trans, glm.vec3[0.5, -0.5, 0.0]*np.sin[glfw.get_time[]]]
    trans = glm.rotate[trans, glfw.get_time[], glm.vec3[0.0, 0.0, 1.0]]
    trans = glm.scale[trans, glm.vec3[1.0, 1.0, 0.0]*[np.sin[glfw.get_time[]]*0.5+0.5]]

    shader.use[]
    glUniformMatrix4fv[glGetUniformLocation[shader.shaderProgram, 'transform'], 1, GL_FALSE, glm.value_ptr[trans]]

    glBindVertexArray[VAO]
    glActiveTexture[GL_TEXTURE0]  # 在绑定纹理之前先激活纹理单元
    glBindTexture[GL_TEXTURE_2D, texture]
    # glDrawArrays[GL_TRIANGLES, 0, 3]
    glDrawElements[GL_TRIANGLES, 6, GL_UNSIGNED_INT, None]

    glfw.swap_buffers[window]
    glfw.poll_events[]

shader.delete[]

顶点着色器

import glm

#version 330 core
layout [location = 0] in vec3 aPos;
layout [location = 1] in vec3 aColor;
layout [location = 2] in vec2 aTexCoord;

out vec3 ourColor;
out vec2 TexCoord;

uniform mat4 transform;

void main[]
{
    gl_Position = transform * vec4[aPos, 1.0];
    ourColor = aColor;
    TexCoord = aTexCoord;
}

片段着色器

import glm

• import glm
  

  1见：基于Python的OpenGL 02 之着色器 - 当时明月在曾照彩云归 - 博客园 [cnblogs. com]

5. 参考资料

[1]变换 - LearnOpenGL CN [learnopengl-cn. github. i]

[2]glm/thủ công. md tại master · g-truc/glm [github. com]

[3]OpenGL学习笔记三——引入GLM库，实现transform_绿洲守望者的博客-CSDN博客_glm库

[4]OpenGL学习笔记（五）纹理 - 知乎 [zhihu. com]

[5]PyGLM · PyPI

[6]Tìm hiểu OpenGL-Python/các phép biến đổi. py ở bậc thầy · Zuzu-Typ/LearnOpenGL-Python [github. com]

作者：当时明月在曾照彩云归

出处：https. //www. cnblog. com/jiujiubashiyi/p/16564571. html

đã đăng @ 2022-08-09 00. 59   当时明月在曾照彩云归  阅读[ 63 ]  评论[ 0 ]  编辑  收藏  举报

GLM viết tắt của OpenGL là gì?

GLM có phải là một thư viện tốt không?

GLM có phải là thư viện tiêu đề không?