OpenGL：是否可以使用glMaterialfv（）创建透明/半透明的对象？

Question

I have this cylinder object below:

glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, cylinder_mat);
cylinder();

Where static GLfloat cylinder_mat[] = {0.f, .5f, 1.f, 1.f}; dictates the color of my cylinder.

Is there anyway to use glMaterialfv in a way to make the object transparent?

Answer 1

I guess this example will clarify a bit for you.

#include <GL/freeglut.h>

void init()
{
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  glClearColor(1.0, 1.0, 1.0, 1.0);
}

void display(void)
{
  glClear(GL_COLOR_BUFFER_BIT);
  glLoadIdentity();

  glColor4f(0.5, 0.5, 0.5, 1.0);
  glutSolidCube(0.5);

  glTranslatef(-0.1, 0, 0);
  glEnable(GL_BLEND);
  glColor4f(1, 0, 0, 0.3);
  glutSolidCube(0.4);
  glDisable(GL_BLEND);

  glFlush();
}

int main(int argc, char *argv[])
{
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE|GLUT_RGBA);
  glutInitWindowSize(600,600);
  glutInitWindowPosition(200,50);
  glutCreateWindow("glut test");
  glutDisplayFunc(display);
  init();
  glutMainLoop();
  return 0;
}

Note that this example is very, very simplicist. So, its main purpose is just to demostrate how to use BLEND functions. I did not take care about DEPTH removal or camera position.

I used the program posted here ( How to use alpha transparency in OpenGL? ) to construct this one.