#include <GL/glut.h> 
#include <stdlib.h> 
#include <stdio.h> 

#define TEX_HEIGHT 512
#define TEX_WIDTH 512
static GLubyte image[TEX_HEIGHT][TEX_WIDTH][4]; 


void initTexture(void)
{
 FILE *fp;
 int i, j, c;

 if((fp = fopen("tri.bmp", "rb")) == NULL){
  fprintf(stderr, "texture file cannot open\n");
  return;
 }

 //bmpファイルのヘッダ部(先頭から54byte)読み飛ばし
 fseek(fp, 54L, SEEK_SET);

 for(i = 0 ; i < TEX_HEIGHT ; i++){
  for(j = 0 ; j < TEX_WIDTH ; j++){
   image[i][j][2]= (GLubyte)fgetc(fp); //B
   image[i][j][1]= (GLubyte)fgetc(fp); //G
   image[i][j][0]= (GLubyte)fgetc(fp); //R
   image[i][j][3]= 0;
  }
 }
 fclose(fp);
}


void displayTexPolygon(void)
{
  glColor3d(1.0,0.0,1.0);
 glBegin(GL_TRIANGLES);//123
 glVertex3f(0.0, 10.0, 0.0); 
 glVertex3f(0.0, 0.0, 10.0); 
 glVertex3f(10.0, 0.0, 0.0);
 glEnd(); 
 
  glColor3d(1.0,0.0,0.0);
 glBegin(GL_TRIANGLES);//124
   glVertex3f(10.0, 0.0, 0.0); 
   glVertex3f(0.0, 0.0, 10.0); 
   glVertex3f(0.0, -10.0, 0.0);
 glEnd();
  
 glColor3d(1.0,1.0,1.0);
 glEnable(GL_TEXTURE_2D);
glBegin(GL_TRIANGLES);//413
  glTexCoord2f(0.5, 1.0); glVertex3f(0.0, -10.0, 0.0); 
  glTexCoord2f(1.0, 0.0); glVertex3f(10.0, 0.0, 0.0);
  glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 10.0, 0.0); 
 glEnd();
 glDisable(GL_TEXTURE_2D);

 glColor3d(0.0,1.0,1.0);
 glBegin(GL_TRIANGLES);//324
  glVertex3f(0.0, 10.0, 0.0); 
  glVertex3f(0.0, 0.0, 10.0); 
  glVertex3f(0.0, -10.0, 0.0);
 glEnd();
}


void display(void)
{
 static float spin = 0.0;
 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 
 glPushMatrix(); 
 {
  glTranslatef(0.0, 0.0,-20.0);
  glRotatef(spin, 0.0, 1.0, 0.0);
  glColor3f(1.0, 1.0, 1.0); 
  displayTexPolygon(); 
 }
 spin += 0.1;
 glPopMatrix();
 glFlush();
 glutSwapBuffers();
}


void init(void)
{
 glClearColor(0.0, 0.0, 0.0, 0.0); 
 glDepthFunc(GL_LEQUAL); 
 glEnable(GL_DEPTH_TEST); 
 initTexture(); 
 glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); 
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 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, GL_RGBA, TEX_WIDTH, TEX_HEIGHT, 0, GL_RGBA, GL_UNSIGNED_BYTE, image); 
} 


void reshape(int w, int h)
{
 glViewport(0, 0, (GLsizei) w, (GLsizei) h); 
 glMatrixMode(GL_PROJECTION); 
 glLoadIdentity(); 
 glFrustum(-10.0, 10.0,-10.0, 10.0, 10.0, 500.0);
 glMatrixMode(GL_MODELVIEW); 
 glLoadIdentity();
}


int main(int argc, char **argv)
{
 glutInit(&argc, argv); 
 glutInitDisplayMode (GLUT_DEPTH|GLUT_DOUBLE|GLUT_RGBA); 
 glutInitWindowSize (342, 342); 
 glutInitWindowPosition (300, 200); 
 glutCreateWindow (argv[0]); 
 init(); 
 glutIdleFunc(display); 
 glutDisplayFunc(display); 
 glutReshapeFunc(reshape);
 glutMainLoop(); 
 return 0; 
}