图形透明贴图

#include <GL/glut.h>
#include <stdio.h>
#include "bitmap.h"

GLfloat LightAmbient[]= { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat LightDiffuse[]= { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat LightPosition[]={ 0.0f, 0.0f, 2.0f, 1.0f };

GLuint texture[3];
GLubyte* TextureImage;
BITMAPINFO *info;

GLfloat xrot;    // X Rotation
GLfloat yrot;    // Y Rotation
GLfloat zrot;
GLfloat xspeed;    // X Rotation Speed
GLfloat yspeed;    // Y Rotation Speed
GLfloat z=-5.0f;   // Depth Into The Screen

void loadtexture()
{
 // Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit
     TextureImage=LoadDIBitmap("1.bmp",&info);       
  glGenTextures(3, &texture[0]);     // Create Three Textures

  // Create Nearest Filtered Texture
  glBindTexture(GL_TEXTURE_2D, texture[0]);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);
  glTexImage2D(GL_TEXTURE_2D, 0, 3, info->bmiHeader.biWidth, info->bmiHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE,TextureImage);

  // Create Linear Filtered Texture
  glBindTexture(GL_TEXTURE_2D, texture[1]);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
  glTexImage2D(GL_TEXTURE_2D, 0, 3, info->bmiHeader.biWidth, info->bmiHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE,TextureImage);

  // Create MipMapped Texture
  glBindTexture(GL_TEXTURE_2D, texture[2]);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
  glTexImage2D(GL_TEXTURE_2D, 0, 3, info->bmiHeader.biWidth, info->bmiHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE,TextureImage);
}

void reader()
{
  glEnable(GL_BLEND);   
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);   
  
   glClearColor(0, 0, 0, 0.0);

 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
 glLoadIdentity();         // Reset The View
 glTranslatef(0.0f,0.0f,z);

 glRotatef(xrot,1.0f,0.0f,0.0f);
 glRotatef(yrot,0.0f,1.0f,0.0f);
 glRotatef(zrot,0,0,1);

 glBindTexture(GL_TEXTURE_2D, texture[0]);
 glColor4f(0.0f,0.8,0.5,0.3);

 glBegin(GL_QUADS);
  // Front Face
  glNormal3f( 0.0f, 0.0f, 1.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  // Back Face
  glNormal3f( 0.0f, 0.0f,-1.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
  // Top Face
  glNormal3f( 0.0f, 1.0f, 0.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
  // Bottom Face
  glNormal3f( 0.0f,-1.0f, 0.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
  // Right face
  glNormal3f( 1.0f, 0.0f, 0.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f,  1.0f, -1.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f,  1.0f,  1.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f,  1.0f);
  // Left Face
  glNormal3f(-1.0f, 0.0f, 0.0f);
  glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
  glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f,  1.0f);
  glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f,  1.0f,  1.0f);
  glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f,  1.0f, -1.0f);
 glEnd();
 glFlush();

}

void shape(int w,int h)
{
 if (w==0)          // Prevent A Divide By Zero By
 {
  w=1;          // Making Height Equal One
 }

 glViewport(0,0,w,h);      // Reset The Current Viewport

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

 // Calculate The Aspect Ratio Of The Window
 gluPerspective(45.0f,(GLfloat)w/(GLfloat)h,0.1f,500);

 glMatrixMode(GL_MODELVIEW);       // Select The Modelview Matrix
 glLoadIdentity();   
}
void init()
{
 loadtexture();
  glShadeModel(GL_FLAT);   
  glEnable(GL_TEXTURE_2D);       // Enable Texture Mapping
 glShadeModel(GL_SMOOTH);       // Enable Smooth Shading
 glClearColor(0.0f, 0.0f, 0.0f, 0.5f);    // Black Background
 glClearDepth(1.0f);         // Depth Buffer Setup
 glEnable(GL_DEPTH_TEST);       // Enables Depth Testing
 glDepthFunc(GL_LEQUAL);        // The Type Of Depth Testing To Do
 glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations

 glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);  // Setup The Ambient Light
 glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);  // Setup The Diffuse Light
 glLightfv(GL_LIGHT1, GL_POSITION,LightPosition); // Position The Light
 glEnable(GL_LIGHT1);
}

void keyspecial(int button,int x,int y)
{
 if (button == GLUT_KEY_DOWN)
  xrot += 10;
 else if (button == GLUT_KEY_UP)
  yrot += 10;
 else if (button == GLUT_KEY_LEFT)
  zrot += 10;
 
 glutPostRedisplay();
}

int main(int argc,char **argv)
{
 glutInit(&argc,argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutCreateWindow("我的第一个opengl");
 glutDisplayFunc(reader);
 glutReshapeFunc(shape);
 glutSpecialFunc(keyspecial);
 init();
 glutMainLoop();
 return 0;
}