OpenGL de プログラミング

ウィンドウに描画したものをキャプチャして、
それをテクスチャにはれ。

　→ウィンドウのキャプチャと保存

#include <cstdio>
#include <iostream>
#include <GL/glut.h>
#include <GL/glu.h>
#include <GL/gl.h>

void display();
void reshape(int w, int h);

inline void DRAW_SQU();
inline void CREATE_IMAGE();
void LOAD_TEXTURE(char *data);


using namespace std;


/*****[テクスチャ関連]*****/
GLuint texture[1];


inline void GLUT_INIT()
{
glutInitDisplayMode(GLUT_RGBA| GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize(200,200);
}

inline void GLUT_CALL_FUNC()
{
glutDisplayFunc(display);
glutReshapeFunc(reshape);

}

inline void MY_INIT()
{
glClearColor(1.0, 1.0, 1.0, 1.0);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
}


int main(int argc, char **argv)
{
glutInit(&argc,argv);
GLUT_INIT();
glutCreateWindow("window name");
GLUT_CALL_FUNC();
MY_INIT();
glutMainLoop();

return 0;
}


/********[ここからコールバック]****************************************/
void display()
{

static float light_pos[] = { 0.0, 3.0, 5.0, 1.0 };
static float red[] = { 0.8, 0.2, 0.2, 1.0 };
static float green[] = { 0.2, 0.8, 0.2, 1.0 };

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

glLoadIdentity();
gluLookAt(3.0, 4.0, 5.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0);

glLightfv(GL_LIGHT0, GL_POSITION, light_pos);


glEnable(GL_DEPTH_TEST);

glPushMatrix();
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, red);
glutSolidCube(1);
glPopMatrix();

glPushMatrix();
glTranslated(0,1,0);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, green);
glutSolidSphere(0.5,20,20);
glPopMatrix();


CREATE_IMAGE();


glDisable(GL_LIGHTING);
glDisable(GL_LIGHT0);


glPushMatrix();
glTranslated(2,0,0);
DRAW_SQU();
glPopMatrix();


glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);

glDisable(GL_DEPTH_TEST);

glutSwapBuffers();

}


void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(30.0, (double)w / (double)h, 1.0, 100.0);
glMatrixMode(GL_MODELVIEW);

}


inline void CREATE_IMAGE()
{
static bool Image_Load = true;
if(Image_Load==true)
{
char *data;
data = new char[glutGet(GLUT_WINDOW_WIDTH)*glutGet( GLUT_WINDOW_HEIGHT)*3];
LOAD_TEXTURE(data);
delete [] data;
Image_Load =false;
}

}

void LOAD_TEXTURE(char *data)
{

glReadPixels(0,0, glutGet(GLUT_WINDOW_WIDTH),glutGet( GLUT_WINDOW_HEIGHT),
GL_RGB,GL_UNSIGNED_BYTE,data);


/******* テクスチャ作成 ****************/
glGenTextures(1, &texture[0]);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);

gluBuild2DMipmaps(GL_TEXTURE_2D, 3,glutGet(GLUT_WINDOW_WIDTH),glutGet( GLUT_WINDOW_HEIGHT), GL_RGB,GL_UNSIGNED_BYTE, data);


}


inline void DRAW_SQU()
{
glEnable(GL_TEXTURE_2D);
glBegin(GL_QUADS);

glTexCoord2d(0.0, 1.0);
glVertex2d(-1,1);

glTexCoord2d(0.0, 0.0);
glVertex2d(-1,-1);

glTexCoord2d(1.0, 0.0);
glVertex2d(1,-1);

glTexCoord2d(1.0, 1.0);
glVertex2d(1,1);

glEnd();

glDisable(GL_TEXTURE_2D);
}