使用带有PyQt5和OpenGL的VBO绘制多个对象？

问题描述

我正在尝试使用pyqt5在pyopengl中渲染多个对象。在遵循了教程之后，我创建了一个3D网格，该网格上传了波前obj文件并使用纹理进行渲染。这对我有用：

class Model:
    def __init__(self,file_name,texture_name):
        self.object = ObjectLoader()
        self.object.load_model(file_name)

        //creating and compiling shaders

        gluseProgram(shader)

        vertex_buffer_object = gluint(0)
        glGenBuffers(1,vertex_buffer_object)
        glBindBuffer(GL_ARRAY_BUFFER,vertex_buffer_object)
        glBufferData(GL_ARRAY_BUFFER,len(self.object.model) * 4,self.object.c_model,GL_DYNAMIC_DRAW) 
        glDrawArrays(GL_TRIANGLES,len(self.object.vertex_index))
        # vertices
        vertex_offset = 0
        glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,self.object.model.itemsize * 3,ctypes.c_void_p(vertex_offset))
        glEnabLevertexAttribArray(0)

        # textures
        texture_offset = len(self.object.vertex_index) * 12
        glVertexAttribPointer(1,2,self.object.model.itemsize * 2,ctypes.c_void_p(texture_offset))
        glEnabLevertexAttribArray(1)

        # normals
        normal_offset = texture_offset + len(self.object.texture_index) * 8
        glVertexAttribPointer(2,ctypes.c_void_p(normal_offset))
        glEnabLevertexAttribArray(2)

        texture = gluint(0)
        glGenTextures(1,texture)
        glBindTexture(GL_TEXTURE_2D,texture)
        # texture wrapping
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT)
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT)
        # texture filtering
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST)
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST)

        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA)

        image = Image.open(texture_name)
        flipped_image = image.transpose(Image.FLIP_TOP_BottOM)
        image_data = image.convert("RGB").tobytes()
        glTexImage2D(GL_TEXTURE_2D,GL_RGB,image.width,image.height,GL_UNSIGNED_BYTE,image_data)
      // setting the view,projection etc matrix     

由于我正在使用PyQt5，因此在加载对象时就拥有此类：

class Obj(qopenglwidget):
    def __init__(self,parent):
        qopenglwidget.__init__(self,parent)
           
    def initializeGL(self):
        glClearColor(82/255,95/255,107/255,1.0)
        glEnable(GL_DEPTH_TEST)         
        
        self.model = Model("....obj","texture.png")     
            
        
    def paintGL(self):
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        glDrawArrays(GL_TRIANGLES,len(self.model.object.vertex_index))
        
   
        self.update()
        
        
    def resizeGL(self,width,height):
        glViewport(0,height)

我正在努力的是在Obj类中创建另一个Model。我尝试在initializeGL中创建它，并在另一个paintGL调用中在glDrawArrays中渲染，但是什么也没发生，或者什么也没想到……我在做什么错了吗？

解决方法

您必须使用Vertex Array Object。顶点数组对象存储提供顶点数据所需的所有状态。

模型的构造函数仅创建所有必需的OpenGL对象。着色器程序不是模型的一部分。对所有模型使用相同的程序：

class Model:
    def __init__(self,file_name,texture_name):
        self.object = ObjectLoader()
        self.object.load_model(file_name)

        # create vertex array object
        self.vao = glGenVertexArrays(1)
        glBindVertexArray(self.vao)

        vertex_buffer_object = GLuint(0)
        glGenBuffers(1,vertex_buffer_object)
        glBindBuffer(GL_ARRAY_BUFFER,vertex_buffer_object)
        glBufferData(GL_ARRAY_BUFFER,len(self.object.model) * 4,self.object.c_model,GL_DYNAMIC_DRAW) 
        glDrawArrays(GL_TRIANGLES,len(self.object.vertex_index))

        # vertices
        vertex_offset = 0
        glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,self.object.model.itemsize * 3,ctypes.c_void_p(vertex_offset))
        glEnableVertexAttribArray(0)

        # textures
        texture_offset = len(self.object.vertex_index) * 12
        glVertexAttribPointer(1,2,self.object.model.itemsize * 2,ctypes.c_void_p(texture_offset))
        glEnableVertexAttribArray(1)

        # normals
        normal_offset = texture_offset + len(self.object.texture_index) * 8
        glVertexAttribPointer(2,ctypes.c_void_p(normal_offset))
        glEnableVertexAttribArray(2)

        # create texture
        self.texture = GLuint(0)
        glGenTextures(1,self.texture)
        glBindTexture(GL_TEXTURE_2D,self.texture)
        # texture wrapping
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT)
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT)
        # texture filtering
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST)
        glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST)

        image = Image.open(texture_name)
        flipped_image = image.transpose(Image.FLIP_TOP_BOTTOM)
        image_data = image.convert("RGB").tobytes()
        glTexImage2D(GL_TEXTURE_2D,GL_RGB,image.width,image.height,GL_UNSIGNED_BYTE,image_data)

向类添加一个方法，该方法绑定OpenGL对象（VAO和纹理）并绘制网格：

class Model:
    # [...]

    def draw(self):

        // bind texture
        glBindTexture(GL_TEXTURE_2D,self.texture)

        // create vertex array object
        glBindVertexArray(self.vao)

        // draw object
        glDrawArrays(GL_TRIANGLES,len(self.object.vertex_index))

使用此设置，您可以绘制多个模型：

class Obj(QOpenGLWidget):
    def __init__(self,parent):
        QOpenGLWidget.__init__(self,parent)

    def initializeGL(self):
        glClearColor(82/255,95/255,107/255,1.0)
        glEnable(GL_DEPTH_TEST)
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA)

        self.model1 = Model("....obj","texture.png") 
        self.model2 = Model("....obj","texture2.png")  
        # [...] 

    def paintGL(self):
        
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
        
        # install program
        glUseProgram(self.shader)

        # setting the view,projection etc matrix
        # [...]
        
        self.model1.draw()
        self.model2.draw()
        # [...] 
        
        self.update()
        
    def resizeGL(self,width,height):
        glViewport(0,height)

模型也可以按列表组织：

class Obj(QOpenGLWidget):
   # [...]

    def initializeGL(self):
        # [...]

        self.models = [
            Model("....obj","texture.png"),Model("....obj","texture2.png")  
            # [...]
        ] 

    def paintGL(self):
        # [...]

        for model in self.models:
            model.draw()

        # [...]