REVISED: Friday, March 22, 2013
CONTENTS:
I. INTRODUCTION
II. INSTALLING OPENGL
III. USING FLTK IN MICROSOFT VISUAL STUDIO
IV. 3D ANIMATION USING FLTK AND OPENGL
YOU WILL LEARN HOW TO:
1. INSTALL AND USE OPENGL WITH FLTK.
2. CODE 3D ANIMATION WITH FLTK OPENGL.
• I. INTRODUCTION
Welcome to the “C++ FLTK OPENGL 3D ANIMATION TUTORIAL"
• II. INSTALLING OPENGL
There are lots of free download websites you can Google; this is one of the many for OpenGL95:
http://download-opengl-graphics.com/
Download and use WinZip or a similar package to extract the OpenGL95.zip file to your C:\ drive.
• III. USING FLTK IN MICROSOFT VISUAL STUDIO
Use the following steps to use OpenGL with FLTK in Microsoft Visual Studio:
1. Open Visual Studio
Use the same Win32 console application empty project you have been using for all of your non-OpenGL FLTK applications.
2. From the Visual Studio main top menu choose Project and from the drop-down menu choose Properties.
To expand a sub-menu click the Linker folder in the left menu of the Properties dialog box. In the sub-menu click Input. On the right, in the additional dependencies text field you should see the following entries we added for FLTK:
At the end of this list add the following four libraries:
opengl32.lib glu32.lib fltkgld.lib glaux.lib
In the “Ignore Specific Library” text field you should already have the following text if you do not have it add it now:
libcd.lib
In the left menu of the Properties window click C\C++ to expand a sub-menu. Click the “Code Generation” sub-menu item. On the right, if it has not already been changed, change the “Runtime Library” drop-down to:
Multi-threaded Debug DLL (\MDd)
Click OK to close the Properties window.
• IV. 3D ANIMATION USING FLTK AND OPENGL
Please copy and paste the following example into your IDE. You have to use the same Project file we just setup. It will not work in other Project files until you set them up the same way we did the one above. Then, build and debug the example program to test to see if you can now code in OpenGL using FLTK.
//***********************************
//Texture Mapped Cube
//erco/loic 03/17/09
//***********************************
#include <cmath>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#include <stdio.h>
#include <math.h>
#include <FL/Fl.H>
#include <FL/Fl_window.H>
#include <FL/Fl_Gl_window.H>
#include <FL/gl.h>
//***********************************
//OpenGL spinning cube with
//checker texturemap
//***********************************
#define WIN_W 400
//window width
#define WIN_H 400
//window height
#define TEX_W 64
//texturemap width
#define TEX_H 64
//texturemap height
#define FPS (1.0/24.0)
//frames per second playback
//***********************************
//OpenGL class to show
//texturemapped cube
//***********************************
class MyGlWindow : public Fl_Gl_Window {
double spin;
GLuint TexID;
//***********************************
//TIMER CALLBACK
//Handles rotation the object
//***********************************
static void Timer_CB(void *userdata) {
MyGlWindow *mygl = (MyGlWindow*)userdata;
mygl->spin += 2.0;
//spin
mygl->redraw();
Fl::repeat_timeout(FPS, Timer_CB, userdata);
}
public:
//CTOR
MyGlWindow(int x,int y,int w,int h,const char *l=0) : Fl_Gl_Window(x,y,w,h,l) {
spin = 0.0;
Fl::add_timeout(FPS, Timer_CB, (void*)this);
//24fps timer
}
//***********************************
//PERSPECTIVE VIEW
//Same as gluPerspective()..
//***********************************
void Perspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar) {
GLdouble xmin, xmax, ymin, ymax;
ymax = zNear * tan(fovy * M_PI / 360.0);
ymin = -ymax;
xmin = ymin * aspect;
xmax = ymax * aspect;
glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
}
//***********************************
//RESHAPED VIEWPORT
//OpenGL
//window changes size
//***********************************
void ReshapeViewport() {
//***********************************
//Viewport
//***********************************
glViewport(0, 0, w(), h());
//***********************************
//Projection
//***********************************
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
GLfloat ratio = w() / h();
Perspective(30.0, 1.0*ratio, 1.0, 30.0);
glTranslatef(0.0, 0.0, -8.0);
//***********************************
//Model view
//***********************************
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
//***********************************
//OPENGL INITIALIZATION
//OpenGL do *only once* on startup.
//***********************************
void GlInit() {
//***********************************
//Make sure we only do this once
//***********************************
static int first_time = 1;
if ( first_time ) {
first_time = 0;
//***********************************
//Texture Map Init
//***********************************
GLubyte img[TEX_W][TEX_H][3]; //after glTexImage2D(), array is no longer needed
glGenTextures(1, &TexID);
glBindTexture(GL_TEXTURE_2D, TexID);
//***********************************
//Texture Mapping Mode
//Uncomment one of the following lines:
//GL_DECAL or GL_MODULATE
//glTexEnvf(GL_TEXTURE_ENV,
//GL_TEXTURE_ENV_MODE,
//GL_DECAL);
//use actual texture colors
//***********************************
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
//texture colors affected by poly's color
for (int x=0; x<TEX_W; x++) {
for (int y=0; y<TEX_H; y++) {
//***********************************
//Texture Pattern
//Uncomment one of the following lines:
//checkboard or basketweave
//GLubyte c = ((x&16)^(y&16)) ? ((x%16)
//<<4) : (((x%16)^15)<<4); //basket weave
//***********************************
GLubyte c = ((x&16)^(y&16)) ? 255 : 0;
//checkerboard
img[x][y][0] = c;
img[x][y][1] = c;
img[x][y][2] = c;
}
}
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, TEX_W, TEX_H, 0, GL_RGB, GL_UNSIGNED_BYTE, &img[0][0][0]);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glEnable(GL_TEXTURE_2D);
//***********************************
//OpenGL settings
//***********************************
glShadeModel(GL_FLAT);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
}
}
//***********************************
//FLTK DRAW
//Called by FLTK to draw the scene.
//***********************************
void draw() {
//***********************************
//Initialize/handle reshaped viewport
//***********************************
if ( !valid() ) {
valid(1);
GlInit();
ReshapeViewport();
}
//***********************************
//Clear
//***********************************
glClearColor(.5,.5,.5, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
//***********************************
//Setup model matrix
//***********************************
glLoadIdentity();
glRotatef(spin, 0.5, 1.0, 0.0);
//show all sides of cube
//***********************************
//Draw cube with texture assigned
//to each face
//***********************************
glBegin(GL_QUADS);
//***********************************
//Front Face
//***********************************
glColor3f(1.0, 0.0, 0.0);
//red
glTexCoord2f(0.0, 1.0); glVertex3f(-1.0, 1.0, 1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f( 1.0, 1.0, 1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f( 1.0, -1.0, 1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, -1.0, 1.0);
//Bottom Left Of The Texture and Quad
//***********************************
//Back Face
//***********************************
glColor3f(0.0, 1.0, 1.0);
//cyn
glTexCoord2f(0.0, 1.0); glVertex3f( 1.0, 1.0, -1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f(-1.0, 1.0, -1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0, -1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0, -1.0);
//Bottom Left Of The Texture and Quad
//***********************************
//Top Face
//***********************************
glColor3f(0.0, 1.0, 0.0);
//grn
glTexCoord2f(0.0, 1.0); glVertex3f(-1.0, 1.0, -1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f( 1.0, 1.0, -1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f( 1.0, 1.0, 1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, 1.0, 1.0);
//Bottom Left Of The Texture and Quad
//***********************************
//Bottom Face
//***********************************
glColor3f(1.0, 0.0, 1.0);
//mag
glTexCoord2f(0.0, 1.0); glVertex3f( 1.0, -1.0, -1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f(-1.0, -1.0, -1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0, 1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0, 1.0);
//Bottom Left Of The Texture and Quad
//***********************************
//Right face
//***********************************
glColor3f(0.0, 0.0, 1.0);
//blu
glTexCoord2f(0.0, 1.0); glVertex3f( 1.0, 1.0, 1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f( 1.0, 1.0, -1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f( 1.0, -1.0, -1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f( 1.0, -1.0, 1.0);
//Bottom Left Of The Texture and Quad
//***********************************
//Left Face
//***********************************
glColor3f(1.0, 1.0, 0.0);
//yel
glTexCoord2f(0.0, 1.0); glVertex3f(-1.0, 1.0, -1.0);
//Top Left Of The Texture and Quad
glTexCoord2f(1.0, 1.0); glVertex3f(-1.0, 1.0, 1.0);
//Top Right Of The Texture and Quad
glTexCoord2f(1.0, 0.0); glVertex3f(-1.0, -1.0, 1.0);
//Bottom Right Of The Texture and Quad
glTexCoord2f(0.0, 0.0); glVertex3f(-1.0, -1.0, -1.0);
//Bottom Left Of The Texture and Quad
glEnd();
//***********************************
//DEBUG: CHECK FOR ERRORS
//***********************************
GLenum err = glGetError();
if ( err != GL_NO_ERROR ) {
fprintf(stderr, "GLGETERROR=%d\n", (int)err);
}
}
};
int main(int argc, char *argv[]) {
MyGlWindow* mygl = new MyGlWindow(10, 10, WIN_W-20, WIN_H-20, "Texture Test");
mygl->end();
mygl->resizable(mygl);
mygl->show();
return(Fl::run());
}
YOU HAVE LEARNED HOW TO:
1. INSTALL AND USE OPENGL WITH FLTK.
2. CODE 3D ANIMATION WITH FLTK OPENGL.
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