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所以我可以使用 OpenGL3.2+ 绘制一个旋转的立方体并将其从 0,0,0 向左平移，但是当我尝试绘制第二个（向右）时，它不会渲染.. .

这是我的显示功能：

    void display()                                  
    {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glUseProgram(myShader.handle());

    GLuint matLocation = glGetUniformLocation(myShader.handle(), "ProjectionMatrix");
    glUniformMatrix4fv(matLocation, 1, GL_FALSE, &ProjectionMatrix[0][0]);

    spinY+=0.03;
    if(spinY>360) spinY = 0;

    glm::mat4 viewMatrix;
    viewMatrix = glm::translate(glm::mat4(1.0),glm::vec3(0,0,-100));        //viewing matrix
    ModelViewMatrix = glm::translate(viewMatrix,glm::vec3(-30,0,0));        //translate object from the origin
    ModelViewMatrix = glm::rotate(ModelViewMatrix,spinY, glm::vec3(0,1,0));                 //rotate object about y axis

    glUniformMatrix4fv(glGetUniformLocation(myShader.handle(), "ModelViewMatrix"), 1, GL_FALSE, &ModelViewMatrix[0][0]); //pass matrix to shader

    //Add the following line just before the line to draw the cube to 
    //check that the origin of the cube in eye space is (-30, 0, -100);
    result = glm::vec3(ModelViewMatrix * glm::vec4(0,0,0,1));
    std::cout<<glm::to_string(result)<<std::endl; //print matrix to get coordinates.

    myCube.render();
    glUseProgram(0);
    }

我希望能够使用相同的 Cube 类/大小等，但只需再次渲染它（我认为这是最有效/最好的方法）。

我试过这个

    void display()                                  
    {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glUseProgram(myShader.handle());

    GLuint matLocation = glGetUniformLocation(myShader.handle(), "ProjectionMatrix");
    glUniformMatrix4fv(matLocation, 1, GL_FALSE, &ProjectionMatrix[0][0]);

    spinY+=0.03;
    if(spinY>360) spinY = 0;

    glm::mat4 viewMatrix;
    viewMatrix = glm::translate(glm::mat4(1.0),glm::vec3(0,0,-100));        //viewing matrix
    ModelViewMatrix = glm::translate(viewMatrix,glm::vec3(-30,0,0));        //translate object from the origin
    ModelViewMatrix = glm::rotate(ModelViewMatrix,spinY, glm::vec3(0,1,0));                 //rotate object about y axis

    glUniformMatrix4fv(glGetUniformLocation(myShader.handle(), "ModelViewMatrix"), 1, GL_FALSE, &ModelViewMatrix[0][0]); //pass matrix to shader

    //Add the following line just before the line to draw the cube to 
    //check that the origin of the cube in eye space is (-30, 0, -100);
    result = glm::vec3(ModelViewMatrix * glm::vec4(0,0,0,1));
    std::cout<<glm::to_string(result)<<std::endl; //print matrix to get coordinates.

    myCube.render();

    glm::mat4 viewMatrix_TWO;
    viewMatrix_TWO = glm::translate(glm::mat4(1.0),glm::vec3(0,0,-100));        //viewing matrix
    ModelViewMatrix_TWO = glm::translate(viewMatrix_TWO,glm::vec3(30,0,0));     //translate object from the origin
    ModelViewMatrix_TWO = glm::rotate(ModelViewMatrix_TWO,spinY, glm::vec3(0,1,0));                 //rotate object about y axis

    glUniformMatrix4fv(glGetUniformLocation(myShader.handle(), "ModelViewMatrix_TWO"), 1, GL_FALSE, &ModelViewMatrix[0][0]); //pass matrix to shader

    myCube.render();

    glUseProgram(0);
    }

显然，我实现错了......我怎样才能在屏幕的任一侧获得一个立方体？谢谢。

更新

我意识到，我没有创建第二个立方体对象，但是现在实现了它，它仍然不起作用......我是否混淆了视图/模型矩阵的交互方式？我为每个对象创建了一个新对象......

新代码：

myCube.render();

spinX+=0.03;
if(spinX>360) spinX = 0;

glm::mat4 viewMatrix_Two,ModelViewMatrix_Two;
viewMatrix_Two = glm::translate(glm::mat4(1.0),glm::vec3(0,0,-100));        //viewing matrix
ModelViewMatrix_Two = glm::translate(viewMatrix_Two,glm::vec3(30,0,0));     //translate object from the origin
ModelViewMatrix_Two = glm::rotate(ModelViewMatrix_Two,spinX, glm::vec3(0,1,0));                 //rotate object about y axis

glUniformMatrix4fv(glGetUniformLocation(myShader.handle(), "ModelViewMatrix_Two"), 1, GL_FALSE, &ModelViewMatrix_Two[0][0]); //pass matrix to shader

myCube_Two.render();

更新

着色器：

    uniform mat4 ModelViewMatrix;
    //uniform mat4 ModelViewMatrix_Two; //NOT NEEDED - USED SAME SHADER OBJECT
    uniform mat4 ProjectionMatrix;

    in  vec3 in_Position;  // Position coming in
    in  vec3 in_Color;     // colour coming in
    out vec3 ex_Color;     // colour leaving the vertex, this will be sent to the fragment shader

    void main(void)
    {
    gl_Position = ProjectionMatrix * ModelViewMatrix * vec4(in_Position, 1.0);
    //gl_Position = ProjectionMatrix * ModelViewMatrix_Two * vec4(in_Position, 1.0);
    ex_Color = in_Color;
    }
4

2 回答 2

1

最后，我创建了第二个 Cube 对象，第二个查看矩阵，并将它们与我的着色器中已经建立的模型矩阵一起使用，似乎两个立方体都被单独调用/渲染。

正确的代码是：

    glm::mat4 viewMatrix_Two, ModelViewMatrix_Two;
    viewMatrix_Two = glm::translate(glm::mat4(1.0),glm::vec3(0,0,-200));
    ModelViewMatrix = glm::translate(viewMatrix_Two,glm::vec3(30,0,0));
    ModelViewMatrix = glm::rotate(ModelViewMatrix,spinX, glm::vec3(1,0,0));

    glUniformMatrix4fv(glGetUniformLocation(myShader.handle(), "ModelViewMatrix"), 1, GL_FALSE, &ModelViewMatrix[0][0]); //pass matrix to shader

    myCube_Two.render();
于 2013-10-15T13:26:08.327 回答
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除非您的着色器有一个名为 ModelViewMatrix_Two 的制服，否则这是行不通的。我看不出为什么你的着色器需要另一个统一的模型视图，因为你没有在同一个调用中绘制两个立方体。如果不是问题，您可以发布您的着色器代码吗？

于 2013-10-15T13:05:53.490 回答