SER332 Lecture 03

jgs SER332 Introduction to Graphics and Game Development Lecture 03:
OpenGL Overview Javier Gonzalez-Sanchez [email protected] PERALTA 230U Office Hours: By appointment

jgs Microsoft Visual Studio 2017 Windows 10 Install and Configure

Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 3 jgs
Run the installation file

Select Desktop Development with C++

Install

Restart

Sign up (optional)

Settings: Visual C++ (optional)

Start Page

Create a new project

Select Windows Console Application

Name your Project

Add the code below to test your project

Remove Precompiled Headers § 1. Right click in the project name and select “Properties”. § 2. Select “Not Using Precompiled Headers”

Build (compile)

Build succeeded

Run it

A console will open

§ https://github.com/javiergs/SER332/tree/master/Lecture03 Download the OpenGL libraries

Copy DLL file to Windows/System32

Copy lib and include folders to VC folder

Update VC++ Directories | Include

Update VC++ Directories | lib

Test OpenGL | Copy code from slides 48

Test OpenGL

If you get a glut32.dll error,

… copy the dll file to the project folder

jgs Introduction to OpenGL

OpenGL § OpenGL basic library – most commands § OpenGL Utility (GLU) – some high level commands e.g. generating complex objects, cylinder, sphere § OpenGL Utility Toolkit (GLUT) windowing commands 38

What Is OpenGL? § Software interface to graphics hardware § Competitors: DirectX, Java2D and Java3D,… § Communicate between CPU and GPU via drivers § A client and server execution model

OpenGL Rendering Pipeline

OpenGL as a State Machine § Maintain pipeline states: current color, viewing and projection transformation, polygon drawing modes, etc. glColor3f(1.0f, 0.0f, 0.0f); // <- alter current state // Draw a cube //What color is the cube? glColor3f(0.0, 1.0f, 0.0f); // <- alter current state // Draw a sphere. // What color is the sphere? § Hierarchical state maintenance glPushAttrib(), glPushMatrix(), glPopAttrib(), glPopMatrix(),…

OpenGL Libraries OpenGL core library (GL) #include <GL/gl.h> § OpenGL32 on Windows. GL on most UNIX / LINUX systems (libGL.a) OpenGL Utility Library (GLU) #include <GL/glu.h> § Provides functionality in OpenGL core but avoids having to rewrite code OpenGL Utility Toolkit (GLUT) #include <GL/glut.h> § Provides functionality common to all window systems: Open a window, Get input from mouse and keyboard, Menus, Event-driven § Code is portable but GLUT lacks the functionality of a good toolkit for a specific platform

OpenGL and Related APIs GLUT GLU GL GLX, AGL or WGL X, Win32, Mac O/S software and/or hardware application program OpenGL Motif widget or similar

OpenGL Syntax § GL functions glClearColor(), glEnable(), glPushMatrix() … § GLU functions gluLookAt(), gluPerspective() … § GL constants GL_COLOR_BUFFER_BIT, GL_PROJECTION, GL_MODELVIEW … § Extra letters in some commands indicate the number and type of variables glColor3f(), glVertex3f() … § OpenGL data types: GLfloat, GLdouble, GLint, GLenum, …

jgs GLUT OpenGL Utility Toolkit

GLUT A simplified window system toolkit § Create windows § Initialize display context § Handle basic application events: screen refreshing, timer, resize… § Handle user inputs A higher level geometric toolkit § glutSolidSphere § glutSolidCube

GLUT Application Structure § Configure and open window § Initialize OpenGL state § Register input callback functions: render, resize, input (keyboard, mouse, etc.) § Enter event processing loop

Installation (Windows) § Add glut.h in your include path gl.h and glu.h are included by glut.h § Add glut32.lib in your library path § Add glut32.dll in "windows\system" path

GLUT Window Management § glutInit (&argc, argv); //Glut initialization § glutCreateWindow ("Example"); //Create a window § glutDisplayFunc (myDisplay) //callback function § glutMainLoop() // activate the display window § glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | …) // set initial options § glutInitWindowPosition (x, y); // integer § glutInitWindowSize (width, height ); // integer

Example 1 /** * https://github.com/javiergs/SER332/blob/master/Lecture03/main.c */ #if defined(__APPLE__) #include <GLUT/glut.h> #else #include <GL/glut.h> #endif // main void main(int argc, char** argv){ glutInit(&argc, argv); // glut init glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500,500); // actual window size glutInitWindowPosition(0,0); // window location glutCreateWindow("simple"); myInit(); glutDisplayFunc(myDisplay); glutMainLoop(); //event loop }

jgs Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 51
Javier Gonzalez-Sanchez | SER431 | Spring 2018 | 51 // myInit void myInit() { glClearColor(0.764f, 0.129f, 0.282f, 1.0); // maroon glColor3f(1.0f, 0.843f, 0.0f); // gold // projection transformations glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(-1.0, 1.0, -1.0, 1.0); // units inside }

jgs Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 52
Javier Gonzalez-Sanchez | SER431 | Spring 2018 | 52 // myDisplay void myDisplay() { glClear(GL_COLOR_BUFFER_BIT); // clear the window glBegin(GL_POLYGON); // fill connected polygon glVertex2f(-0.7, 0.7); // vertices of the square glVertex2f( 0.6, 0.7); glVertex2f(-0.7, -0.6); glEnd(); glBegin(GL_POLYGON); // fill connected polygon glVertex2f( 0.7, 0.6); // vertices of the square glVertex2f(-0.6, -0.7); glVertex2f( 0.7, -0.7); glEnd(); glFlush(); //forces issued commands to execute }

Example 1 500 500 (0.7,0.7) (-0.7,-0.7)

Double Buffering Double buffering is necessary for almost all OpenGL applications: § Render into back buffer § Swap buffers when finished rendering a frame: The old back buffer becomes the front buffer that is displayed. The old front buffer becomes the back buffer that is rendered into. § What happens when you do not use double buffering? flickering artifacts, tearing artifacts Commands: § glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE ); § glutSwapBuffers(); //instead of glFlush()

Homework Start Programming!

jgs SER332 Introduction to Graphics Javier Gonzalez-Sanchez [email protected] Spring 2018
Disclaimer. These slides can only be used as study material for the class SER332 at ASU. They cannot be distributed or used for another purpose.

SER332 Lecture 03

SER332 Lecture 03

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