学步园

    今日，我的项目中要给某些构件加上透明度。翻了下红宝书，看了一下alpha3D.c例子。从网上download

这个例子源码，结果发现运行时窗口为透明，没有画出来任命东西。上网搜了搜，看看有没有现成的例子。找了

半天也没有找到，那就自己写吧。希望后来者，再也不用写这种简单的例子了。

    例子描述：画出三个球，一个红球，一个蓝球，一个绿球，红球 在左，蓝球在中，绿球在右，一线排开。

并绕蓝球旋转。红球不透明，蓝球，绿球半透明。如下图：

#include <GL/glut.h><br /> #include <math.h><br /> #include <stdio.h><br /> enum<br /> {<br /> SPHERE = 1, SPHERE2,SPHERE3<br /> };<br /> GLfloat light_diffuse[] = {1.0, 0.0, 0.0, 1.0}; /* Red diffuse light. */<br /> GLfloat light_position[] = {1.0, 1.0, 1.0, 0.0}; /* Infinite light location. */<br /> GLfloat mat_ambient[] = { 0.2f, 0.2f, 0.2f, 1.0f };<br /> GLfloat angle1 = 0.0;<br /> void display(void)<br /> {<br /> glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);<br /> glMatrixMode(GL_MODELVIEW);<br /> glLoadIdentity();<br /> glTranslatef(0.0, 0.0, -50);<br /> glRotatef(angle1, 0.0, 1.0, 0);<br /> glTranslatef(-10.0f,0.0,0.0);<br /> glDisable(GL_BLEND);<br /> glCallList(SPHERE);<br /> glEnable(GL_BLEND);<br /> glDepthMask(GL_FALSE);<br /> glTranslatef(10.0f,0.0,0.0);<br /> glCallList(SPHERE2);<br /> glTranslatef(9.0f,0.0,0.0);<br /> glCallList(SPHERE3);<br /> glDepthMask(GL_TRUE);<br /> glutSwapBuffers();<br /> }<br /> void init(void)<br /> {<br /> GLUquadricObj *sphere, *sphere2, *sphere3;<br /> static GLfloat sphere_mat[] =<br /> {1.f, .5f, 0.f, 1.f};<br /> static GLfloat sphere_mat2[] =<br /> {0.f, .5f, 1.f, 0.3f};<br /> static GLfloat sphere_mat3[] =<br /> {0.1f, 1.0f, 0.0, 0.3f};<br /> /* Enable a single OpenGL light. */<br /> glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);<br /> glLightfv(GL_LIGHT0, GL_POSITION, light_position);<br /> glLightfv(GL_LIGHT0,GL_AMBIENT, mat_ambient);<br /> glEnable(GL_LIGHT0);<br /> glEnable(GL_LIGHTING);<br /> glEnable (GL_BLEND);<br /> glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);<br /> /* Use depth buffering for hidden surface elimination. */<br /> glEnable(GL_DEPTH_TEST);<br /> glClearColor(1.0f, 1.0f, 1.0f, 1.0f);<br /> /* Setup the view of the cube. */<br /> glMatrixMode(GL_PROJECTION);<br /> gluPerspective( /* field of view in degree */ 40.0,<br /> /* aspect ratio */ 1.0,<br /> /* Z near */ 1.0, /* Z far */ 200.0);<br /> /* Adjust cube position to be asthetic angle. */<br /> glNewList(SPHERE, GL_COMPILE);<br /> sphere = gluNewQuadric();<br /> glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, sphere_mat);<br /> gluSphere(sphere, 5.f, 64, 64);<br /> gluDeleteQuadric(sphere);<br /> glEndList();<br /> glNewList(SPHERE2, GL_COMPILE);<br /> sphere2 = gluNewQuadric();<br /> glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, sphere_mat2);<br /> gluSphere(sphere2, 4.f, 64, 64);<br /> gluDeleteQuadric(sphere2);<br /> glEndList();<br /> glNewList(SPHERE3, GL_COMPILE);<br /> sphere3 = gluNewQuadric();<br /> glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, sphere_mat3);<br /> gluSphere(sphere3, 3.f, 64, 64);<br /> gluDeleteQuadric(sphere3);<br /> glEndList();<br /> }<br /> void idle(void)<br /> {<br /> angle1 = (GLfloat) fmod(angle1 + 0.8, 360.0);<br /> glutPostRedisplay();<br /> }<br /> void visible(int vis)<br /> {<br /> if (vis == GLUT_VISIBLE)<br /> glutIdleFunc(idle);<br /> else<br /> glutIdleFunc(NULL);<br /> }<br /> int main(int argc, char **argv)<br /> {<br /> glutInit(&argc, argv);<br /> glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);<br /> glutInitWindowSize(512, 512);<br /> glutCreateWindow("blend 3d");<br /> glutDisplayFunc(display);<br /> glutVisibilityFunc(visible);<br /> init();<br /> glutMainLoop();<br /> return 0;<br /> }<br />