使用openGL

Question

即时通讯尝试用openGL做一个小小的3D场景,并且包含一些照明,我对我的场景很好(虽然它没什么特别的),我试图添加一些照明,以给它一些效果.但是我可以在我的讲台上添加材料(没有纹理),这给了我光线,任何有纹理的东西都不会对它施加任何材料,因此它无视光线.下面是一些代码.

// Setup GL_LIGHT0
glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient);     // Setup ambient light
glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse);     // Setup diffuse light
glLightfv(GL_LIGHT0, GL_SPECULAR, lightSpecular);   // Setup specular light

glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, ca);
glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, la);
glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, qa);

glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 180.0f);
glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 0.0);

// Setup GL_LIGHT1
glLightfv(GL_LIGHT1, GL_AMBIENT, lightAmbient);     // Setup ambient light
glLightfv(GL_LIGHT1, GL_DIFFUSE, lightDiffuse);     // Setup diffuse light
glLightfv(GL_LIGHT1, GL_SPECULAR, lightSpecular);   // Setup specular light

glLightf(GL_LIGHT1, GL_CONSTANT_ATTENUATION, ca);
glLightf(GL_LIGHT1, GL_LINEAR_ATTENUATION, la);
glLightf(GL_LIGHT1, GL_QUADRATIC_ATTENUATION, qa);

glLightf(GL_LIGHT1, GL_SPOT_CUTOFF, 180.0f);
glLightf(GL_LIGHT1, GL_SPOT_EXPONENT, 0.0);
// Setup GL_LIGHT2
glLightfv(GL_LIGHT2, GL_AMBIENT, lightAmbient);     // Setup ambient light
glLightfv(GL_LIGHT2, GL_DIFFUSE, lightDiffuse);     // Setup diffuse light
glLightfv(GL_LIGHT2, GL_SPECULAR, lightSpecular);   // Setup specular light

glLightf(GL_LIGHT2, GL_CONSTANT_ATTENUATION, ca);
glLightf(GL_LIGHT2, GL_LINEAR_ATTENUATION, la);
glLightf(GL_LIGHT2, GL_QUADRATIC_ATTENUATION, qa);

glLightf(GL_LIGHT2, GL_SPOT_CUTOFF, 180.0f);
glLightf(GL_LIGHT2, GL_SPOT_EXPONENT, 0.0);
// Setup GL_LIGHT3
glLightfv(GL_LIGHT3, GL_AMBIENT, lightAmbient);     // Setup ambient light
glLightfv(GL_LIGHT3, GL_DIFFUSE, lightDiffuse);     // Setup diffuse light
glLightfv(GL_LIGHT3, GL_SPECULAR, lightSpecular);   // Setup specular light

glLightf(GL_LIGHT3, GL_CONSTANT_ATTENUATION, ca);
glLightf(GL_LIGHT3, GL_LINEAR_ATTENUATION, la);
glLightf(GL_LIGHT3, GL_QUADRATIC_ATTENUATION, qa);

glLightf(GL_LIGHT3, GL_SPOT_CUTOFF, 180.0f);
glLightf(GL_LIGHT3, GL_SPOT_EXPONENT, 0.0);

// OpenGL provides a global ambient light component - we don't want this so set to zero
GLfloat global_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, global_ambient);

并渲染我的房间+ 3D对象.

glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHT1);
    glEnable(GL_LIGHT2);
    glEnable(GL_LIGHT3);

    // Define position and direction
    // NOTE: Placing these commands AFTER the above viewing (camera) transformations means the light position and direction appear to have a set point / direction in the 3D environment.  If these commands are placed BEFORE the above viewing transformations, then the light appears to move with the camera (as if it is attached to the camera!)
    glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, lightDirection);
    glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);

    glLightfv(GL_LIGHT1, GL_SPOT_DIRECTION, lightDirection1);
    glLightfv(GL_LIGHT1, GL_POSITION, lightPosition1);

    glLightfv(GL_LIGHT2, GL_SPOT_DIRECTION, lightDirection2);
    glLightfv(GL_LIGHT2, GL_POSITION, lightPosition2);

    glLightfv(GL_LIGHT3, GL_SPOT_DIRECTION, lightDirection3);
    glLightfv(GL_LIGHT3, GL_POSITION, lightPosition3);


    // setup materials for objects to draw
    glMaterialfv(GL_FRONT, GL_AMBIENT, ambientMaterial);
    glMaterialfv(GL_FRONT, GL_DIFFUSE, diffuseMaterial);
    glMaterialfv(GL_FRONT, GL_SPECULAR, specularMaterial);


    // 2. Draw scene
    glPushMatrix();
        drawRoom();
        glTranslatef(0.0,-0.75,0.0);
        glRotatef(90.0, 1.0,0.0, 0.0);
        glRotatef(-spin, 0.0,0.0, 1.0);
        glColor3f(1.0, 1.0, 1.0);
        drawPodium();
    glPopMatrix();

    // Save transformations prior to rendering scene
    glPushMatrix();

        glColor3f(0.0, 0.0, 1.0);   

        // Setup texture state
        glEnable(GL_TEXTURE_2D);
        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

        glRotatef(spin, 0.0,1.0, 0.0);
        // Render model

        glMaterialfv(GL_FRONT, GL_DIFFUSE, diffuseMaterial2);

        glTranslatef(0.0,0.8,0.0);
        glRotatef(1.0,1.0,0.0,0.0);
        myModel->renderTexturedModel();

        // Reset texture state
        glDisable(GL_TEXTURE_2D);

    // restore transformations after rendering scene
    glPopMatrix();

我的4盏灯的当前结果,在直升机上方的正方形形状都向下看0.0:

如果你能看出白色的虚线,它们就是灯光的方向.登上领奖台的表面被点亮,领奖台的两侧在旋转时点亮.然而,房间和直升机的其余部分没有响应光线,并且行为就像照明甚至没有启用因此为什么我认为它因为除了讲台之外的所有东西都有纹理.

Answer 1

您需要设置glTexEnv以指定照明应如何对纹理对象起作用

看到:

21.030当我打开纹理贴图时,为什么不点亮工作？ http://www.opengl.org/resources/faq/technical/texture.htm

或者更直接地解决您的问题,该行

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

是导致这种行为的原因.正如常见问题所解释的那样,当您指定GL_REPLACE时,将原始光源颜色替换为纹理颜色,这将覆盖任何光照计算.您可以完全删除此行,因为GL_MODULATE是默认行为.