如何在没有蓝色的所有感觉颜色的情况下将 QUADS 着色为蓝色

Posted 2023-02-22

【中文标题】如何在没有蓝色的所有感觉颜色的情况下将 QUADS 着色为蓝色

【英文标题】：How to color QUADS in blue color without all sense color in the blue

【发布时间】：2018-02-25 11:40:56

【问题描述】：

你好，我在 c++ 中使用 glut 和 opengl，我有家我想在其中绘制蓝色 QUADS，当我将 QUADS 的所有感觉颜色都绘制为蓝色时，我的问题是，所以我如何才能仅将 QUADS 着色为蓝色和防止用蓝色着色所有感觉我做错了什么如何从所有感觉中去除蓝色并仅着色我的 QUAD？ 我的尝试：

void drawSquare1()

    glBegin(GL_QUADS);
    glColor3d(1,0,0);
    glVertex3f(-0.5,-0.5,-0.5);
    glColor3d(1,1,0);
    glVertex3f(0.5,-0.5,-0.5);
    glColor3d(1,1,1);
    glVertex3f(0.5,0.5,-0.5);
    glColor3d(0,1,1);
    glVertex3f(-0.5,0.5,-0.5);
    glEnd();


void render(void)                                                   // Our Rendering Is Done Here


    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);             // Clear The Screen And The Depth Buffer
    glLoadIdentity();                                               // Reset The View

    GLfloat xtrans = -g_xpos;
    GLfloat ztrans = -g_zpos;
    GLfloat ytrans = -g_ypos;
    if(g_yrot > 360)
        g_yrot -= 360;
    else if(g_yrot < 0)
        g_yrot += 360;
    GLfloat sceneroty = (360.0f - g_yrot);


    int numpolygons;

    glRotatef(g_lookupdown,1.0f,0,0);
    glRotatef(sceneroty,0,1.0f,0);

    glTranslatef(xtrans, ytrans, ztrans);

    numpolygons = g_sector1.numpolygons;

    for (int loop_m = 0; loop_m < numpolygons; loop_m++)
        texture_object(loop_m); 

    gluQuadricDrawStyle(my_shape[0],GLU_FILL);
    glBindTexture(GL_TEXTURE_2D, textures[1].texID);
    glScalef(0.1,0.1,0.1);
    glTranslatef(0.78,14.3,-4.2);
    gluSphere(my_shape[0], 1.0,50,50);

    gluQuadricDrawStyle(my_shape[1],GLU_FILL);
    glBindTexture(GL_TEXTURE_2D, textures[8].texID);
    glTranslatef(-20,0,0);
    gluSphere(my_shape[1], 1.0,50,50);

    gluQuadricDrawStyle(my_shape[2],GLU_FILL);
    glBindTexture(GL_TEXTURE_2D, textures[22].texID);
    glTranslatef(40,0,0);
    gluSphere(my_shape[2], 1.0,50,50);

    glMatrixMode(GL_PROJECTION);                                    // Select The Projection Matrix
    glPushMatrix();                                                 // Store The Projection Matrix
    glLoadIdentity();                                               // Reset The Projection Matrix

    glOrtho(-10,window_width,0,window_height,-10,10);                   // Set Up An Ortho Screen
    glMatrixMode(GL_MODELVIEW);                                     // Select The Modelview Matrix
drawSquare1();
glMatrixMode(GL_PROJECTION);                                    // Select The Projection Matrix
    glPopMatrix();                                                  // Restore The Old Projection Matrix
    //glPushMatrix();
    drawSquare1();
    //glPopMatrix();
    glMatrixMode(GL_MODELVIEW);                                     // Select The Modelview Matrix
    glutSwapBuffers ( );


int main(int argc, char** argv)                                 // Main Function For Bringing It All Together.

    //cout << "Hello World!" << endl;
    //cin.get();
    glutInit(&argc, argv);                                      // GLUT Initializtion
    glutInitDisplayMode(GLUT_DEPTH | GLUT_RGBA | GLUT_DOUBLE);  // (CHANGED)
    if (g_gamemode) 
    
        glutGameModeString("640x480:16");                       // Select The 640x480 In 16bpp Mode
        if (glutGameModeGet(GLUT_GAME_MODE_POSSIBLE))
            glutEnterGameMode();                                // Enter Full Screen
        else g_gamemode = false;                                // Cannot Enter Game Mode, Switch To Windowed
    
    screen_width = glutGet(GLUT_SCREEN_WIDTH);
    screen_height = glutGet(GLUT_SCREEN_HEIGHT);
    window_width = screen_width/1.4;
    window_height = screen_height/1.4;

    if (!g_gamemode) 
    
        glutInitWindowSize(window_width,window_height);           // Window Size If We Start In Windowed Mode
        glutInitWindowPosition((screen_width-window_width)/2,(screen_height-window_height)/2);
        glutCreateWindow("Frank's 3-D House");                  // Window Title 
    

    init();


    glutIgnoreKeyRepeat(true);                                  // Disable Auto Repeat (NEW)
    //  glutKeyboardFunc(myKey); // register the key handler.

    glutDisplayFunc(render);                                    // Register The Display Function
    glutReshapeFunc(reshape);                                   // Register The Reshape Handler
    glutKeyboardFunc(keyboard);                                 // Register The Keyboard Handler
    //glRasterPos2f(lineMargin, currentHight); // set the cursor to the initial position.
    glutSpecialFunc(special_keys);                              // Register Special Keys Handler
    glutSpecialUpFunc(special_keys_up);                         // Called When A Special Key Released (NEW)
    glutIdleFunc(game_function);                                // Process User Input And Does Rendering (CHANGED)
    glutMouseFunc(mouse) ;
    glutMainLoop();                                             // Go To GLUT Main Loop
    return 0;

这张运行我的代码的图片：

【参考方案1】：

默认情况下，纹理环境模式 (GL_TEXTURE_ENV_MODE) 为 GL_MODULATE。见glTexEnv。

这意味着如果启用了纹理 (glEnable(GL_TEXTURE_2D))，则纹理的颜色将乘以 glColor 当前设置的颜色。

要解决您的问题，我建议在绘制几何图形之前设置glColor4f(1.0f,1.0f,1.0f,1.0f); ：

void render(void) 

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    .....

    glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
    for (int loop_m = 0; loop_m < numpolygons; loop_m++)
        texture_object(loop_m); 

    .....                                

注意，当前颜色在drawSquare1函数中改变并保持其状态。

【讨论】：

添加 glColor4f(1.0f,1.0f,1.0f,1.0f);感谢您的帮助