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此代码必须绘制两条正弦线。这里两条常用线通过着色器转换为正弦线。我的任务是旋转其中一个（例如，旋转 45 或 90 度），怎么做？

void CMyApplication::OnDraw()
{

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glUseProgramObjectARB(m_program);

    glUniform1fARB(m_amplitudeUniformLocation, 0.3f);
    glUniform1fARB(m_phaseUniformLocation, m_phase);
    glUniform1fARB(m_frequencyUniformLocation, M_PI);
    glUniform1fARB(m_colourUniformLocation, 0.0f);
    //glUniform1fARB(m_rotateUniformLocation, true);
    //glLoadIdentity();
    //glRotatef(90.0f, 0.0f, 0.0f, 0.0f);
    glBegin(GL_LINE_STRIP);
    {
        for (float x = -1; x <= 1.05; x += 0.01)
        {
            glVertex3f(x, 0, 0);
            glColor3f(0, 0.5, -0.8);
        }
    }
    glEnd();
    //glLoadIdentity();
    //glRotatef(-90.0f, 0.0f, 0.0f, 0.0f);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glUniform1fARB(m_phaseUniformLocation, m_phase - 0.5);
    glUniform1fARB(m_colourUniformLocation, 0.5f);
    //glUniform1fARB(m_rotateUniformLocation, false);

    glBegin(GL_LINE_STRIP);
    {
        for (float x = -1; x <= 1.05; x += 0.01)
        {
            glVertex3f(x, -0.5, 0);
            glColor3f(0, -0.5, 0.8);
        }
    }
    glEnd();

    __glewMatrixRotatefEXT(GL_MODELVIEW, 45, 0, 0, 1); //THIS STRING HAS BEEN RESOLVED         //MY PROBLEM

    glUseProgramObjectARB(NULL);

    glutSwapBuffers();
}

下面的着色器：

uniform float phase;                
uniform float amplitude;            
uniform float frequency;                           
void main()                     
{                                   
    vec4 v = gl_Vertex;                                 
    v.y += amplitude * sin(frequency * v.x + phase);    
    gl_Position = gl_ModelViewProjectionMatrix * v;     
    gl_FrontColor = gl_Color;       
 }
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1 回答 1

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因为您正在使用着色器，所以 glRotatef 将无法按预期运行。一旦使用着色器启用可编程管线，固定功能管线转换调用将被关闭。所以本质上，glRotatef 在这里什么都不做，除非你已经在你的顶点着色器中使用了正确的矩阵。

要获得您正在寻找的结果，您需要生成适当的旋转矩阵，将其传递给统一变量中的顶点着色器，然后在应用 WVP 变换之前将其乘以您创建的线。最终结果应该给你旋转的线。

于 2014-01-15T15:29:33.383 回答