#include <IL/il.h>
#include <GL/glut.h>
#define DEFAULT_WIDTH 640
#define DEFAULT_HEIGHT 480
int width = DEFAULT_WIDTH;
int height = DEFAULT_HEIGHT;
/* Handler for window-repaint event. Called back when the window first appears and
whenever the window needs to be re-painted. */
void display()
{
// Clear color and depth buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW); // Operate on model-view matrix
/* Draw a quad */
glBegin(GL_QUADS);
glTexCoord2i(0, 0); glVertex2i(0, 0);
glTexCoord2i(0, 1); glVertex2i(0, height);
glTexCoord2i(1, 1); glVertex2i(width, height);
glTexCoord2i(1, 0); glVertex2i(width, 0);
glEnd();
glutSwapBuffers();
}
/* Handler for window re-size event. Called back when the window first appears and
whenever the window is re-sized with its new width and height */
void reshape(GLsizei newwidth, GLsizei newheight)
{
// Set the viewport to cover the new window
glViewport(0, 0, width=newwidth, height=newheight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, width, height, 0.0, 0.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glutPostRedisplay();
}
/* Initialize OpenGL Graphics */
void initGL(int w, int h)
{
glViewport(0, 0, w, h); // use a screen size of WIDTH x HEIGHT
glEnable(GL_TEXTURE_2D); // Enable 2D texturing
glMatrixMode(GL_PROJECTION); // Make a simple 2D projection on the entire window
glLoadIdentity();
glOrtho(0.0, w, h, 0.0, 0.0, 100.0);
glMatrixMode(GL_MODELVIEW); // Set the matrix mode to object modeling
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClearDepth(0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear the window
}
/* Load an image using DevIL and return the devIL handle (-1 if failure) */
int LoadImage(char *filename)
{
ILboolean success;
ILuint image;
ilGenImages(1, &image); /* Generation of one image name */
ilBindImage(image); /* Binding of image name */
success = ilLoadImage(filename); /* Loading of the image filename by DevIL */
if (success) /* If no error occured: */
{
/* Convert every colour component into unsigned byte. If your image contains alpha channel you can replace IL_RGB with IL_RGBA */
success = ilConvertImage(IL_RGBA, IL_UNSIGNED_BYTE);
if (!success)
{
return -1;
}
}
else
return -1;
return image;
}
int main(int argc, char **argv)
{
GLuint texid;
int image;
if ( argc < 1)
{
/* no image file to display */
return -1;
}
/* GLUT init */
glutInit(&argc, argv); // Initialize GLUT
glutInitDisplayMode(GLUT_DOUBLE); // Enable double buffered mode
glutInitWindowSize(DEFAULT_WIDTH, DEFAULT_HEIGHT); // Set the window's initial width & height
glutCreateWindow(argv[0]); // Create window with the name of the executable
glutDisplayFunc(display); // Register callback handler for window re-paint event
glutReshapeFunc(reshape); // Register callback handler for window re-size event
/* OpenGL 2D generic init */
initGL(DEFAULT_WIDTH, DEFAULT_HEIGHT);
/* Initialization of DevIL */
if (ilGetInteger(IL_VERSION_NUM) < IL_VERSION)
{
printf("wrong DevIL version \n");
return -1;
}
ilInit();
/* load the file picture with DevIL */
image = LoadImage(argv[1]);
if ( image == -1 )
{
printf("Can't load picture file %s by DevIL \n", argv[1]);
return -1;
}
/* OpenGL texture binding of the image loaded by DevIL */
glGenTextures(1, &texid); /* Texture name generation */
glBindTexture(GL_TEXTURE_2D, texid); /* Binding of texture name */
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); /* We will use linear interpolation for magnification filter */
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); /* We will use linear interpolation for minifying filter */
glTexImage2D(GL_TEXTURE_2D, 0, ilGetInteger(IL_IMAGE_BPP), ilGetInteger(IL_IMAGE_WIDTH), ilGetInteger(IL_IMAGE_HEIGHT),
0, ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, ilGetData()); /* Texture specification */
/* Main loop */
glutMainLoop();
/* Delete used resources and quit */
ilDeleteImages(1, &image); /* Because we have already copied image data into texture data we can release memory used by image. */
glDeleteTextures(1, &texid);
return 0;
}
