The Ring programming language version 1.5.1 book - Part 52 of 180
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This document discusses using RingOpenGL and RingFreeGLUT libraries to perform 3D graphics in Ring. It provides examples of creating an OpenGL window with RingFreeGLUT, drawing shapes with RingOpenGL by specifying vertices and colors, handling window resize events, adding triangle rotation, and responding to keyboard input to change shape colors. The examples demonstrate basic 3D rendering functionality and interactivity using these Ring libraries for OpenGL.
The Ring programming language version 1.5.1 book - Part 52 of 180
- 1. CHAPTER FIFTYFOUR USING RINGOPENGL AND RINGFREEGLUT FOR 3D GRAPHICS In this chapter we will learn about using RingOpenGL 54.1 Samples Source (Authors) The samples in this chapter are based on C Tutorials from 1. http://www.lighthouse3d.com/tutorials/glut-tutorial/ 2. http://www.wikihow.com/Make-a-Cube-in-OpenGL 54.2 What is RingOpenGL? RingOpenGL contains the Ring binding to the OpenGL library You can learn about OpenGL from : https://www.opengl.org/ RingOpenGL comes with support for the next versions • OpenGL 1.1 • OpenGL 1.2 • OpenGL 1.3 • OpenGL 1.4 • OpenGL 1.5 • OpenGL 2.0 • OpenGL 2.1 • OpenGL 3.0 • OpenGL 3.2 • OpenGL 3.3 • OpenGL 4.0 • OpenGL 4.1 • OpenGL 4.2 • OpenGL 4.3 485
- 2. Ring Documentation, Release 1.5.1 • OpenGL 4.4 • OpenGL 4.5 • OpenGL 4.6 For example, if you want to use OpenGL 2.1 then load RingOpenGL 2.1 library load "opengl21lib.ring" 54.3 What is RingFreeGLUT? RingFreeGLUT contains the Ring binding to the FreeGLUT library You can learn about FreeGLUT from : http://freeglut.sourceforge.net/ To use the RingFreeGLUT library, Just load the library load "freeglut.ring" 54.4 The First Window using RingFreeGLUT Example: load "freeglut.ring" func main glutInit() glutInitDisplayMode(GLUT_SINGLE) glutInitWindowSize(800, 600) glutInitWindowPosition(100, 10) glutCreateWindow("RingFreeGLUT - Test 1") glutDisplayFunc(:displayCode) glutMainLoop() func displaycode Screen Shot 54.3. What is RingFreeGLUT? 486
- 3. Ring Documentation, Release 1.5.1 54.5 Drawing using RingOpenGL Example: load "freeglut.ring" load "opengl21lib.ring" func main glutInit() glutInitDisplayMode(GLUT_SINGLE) glutInitWindowSize(800, 600) glutInitWindowPosition(100, 10) glutCreateWindow("RingFreeGLUT - Test 2") glutDisplayFunc(:displayCode) glutMainLoop() func displaycode glClear(GL_COLOR_BUFFER_BIT) glColor3f(0,255,0) glBegin(GL_POLYGON) glVertex3f(0.0, 0.0, 0.0) 54.5. Drawing using RingOpenGL 487
- 4. Ring Documentation, Release 1.5.1 glVertex3f(0.5, 0.0, 0.0) glVertex3f(0.5, 0.5, 0.0) glVertex3f(0.0, 0.5, 0.0) glEnd() glColor3f(255,0,0) glBegin(GL_POLYGON) glVertex3f(0.0, 0.0, 0.0) glVertex3f(0.5, 0.0, 0.0) glVertex3f(-0.5,- 1, 0.0) glVertex3f(0.0, -1, 0.0) glEnd() glColor3f(0,0,255) glBegin(GL_POLYGON) glVertex3f(0.0, 0.0, 0.0) glVertex3f(-0.5, 0.0, 0.0) glVertex3f(-0.5,- 0.5, 0.0) glVertex3f(0.0, -0.5, 0.0) glEnd() glFlush() Screen Shot 54.5. Drawing using RingOpenGL 488
- 5. Ring Documentation, Release 1.5.1 54.6 The First Triangle Example: load "freeglut.ring" load "opengl21lib.ring" func main glutInit() glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA) glutInitWindowSize(320,320) glutInitWindowPosition(100, 10) glutCreateWindow("RingFreeGLUT - Test 3") glutDisplayFunc(:renderScene) glutMainLoop() func renderScene glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) glBegin(GL_TRIANGLES) glVertex3f(-0.5,-0.5,0.0) glVertex3f(0.5,0.0,0.0) glVertex3f(0.0,0.5,0.0) glEnd() glutSwapBuffers() Screen Shot 54.6. The First Triangle 489
- 6. Ring Documentation, Release 1.5.1 54.7 Window Resize Event Example: load "freeglut.ring" load "opengl21lib.ring" func main // init GLUT and create window glutInit() glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA) glutInitWindowPosition(100,100) glutInitWindowSize(320,320) glutCreateWindow("RingFreeGLUT - Test 4") glutDisplayFunc(:renderScene) glutReshapeFunc(:changeSize) glutMainLoop() func renderScene glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) glBegin(GL_TRIANGLES) glVertex3f(-2,-2,-5.0) glVertex3f(2,0.0,-5.0) glVertex3f(0.0,2,-5.0) glEnd() glutSwapBuffers() func changesize h = glutEventHeight() w = glutEventWidth() // Prevent a divide by zero, when window is too short // (you cant make a window of zero width). if (h = 0) h = 1 ok ratio = w * 1.0 / h // Use the Projection Matrix glMatrixMode(GL_PROJECTION) // Reset Matrix glLoadIdentity() // Set the viewport to be the entire window glViewport(0, 0, w, h) // Set the correct perspective. gluPerspective(45,ratio,1,100) 54.7. Window Resize Event 490
- 7. Ring Documentation, Release 1.5.1 // Get Back to the Modelview glMatrixMode(GL_MODELVIEW) 54.8 Triangle Rotation Example: load "freeglut.ring" load "opengl21lib.ring" angle = 0 func main // init GLUT and create window glutInit() glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA) glutInitWindowPosition(100,100) glutInitWindowSize(320,320) glutCreateWindow("RingFreeGLUT - Test 5") glutDisplayFunc(:renderScene) glutReshapeFunc(:changeSize) glutIdleFunc(:renderScene) glutMainLoop() func renderScene // Clear Color and Depth Buffers glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) // Reset transformations glLoadIdentity() // Set the camera gluLookAt( 0.0, 0.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0) glRotatef(angle, 0.0, 1.0, 0.0) glBegin(GL_TRIANGLES) glVertex3f(-2.0,-2.0, 0.0) glVertex3f( 2.0, 0.0, 0.0) glVertex3f( 0.0, 2.0, 0.0) glEnd() angle+=0.1 glutSwapBuffers(); func changesize h = glutEventHeight() w = glutEventWidth() 54.8. Triangle Rotation 491
- 8. Ring Documentation, Release 1.5.1 // Prevent a divide by zero, when window is too short // (you cant make a window of zero width). if (h = 0) h = 1 ok ratio = w * 1.0 / h // Use the Projection Matrix glMatrixMode(GL_PROJECTION) // Reset Matrix glLoadIdentity() // Set the viewport to be the entire window glViewport(0, 0, w, h) // Set the correct perspective. gluPerspective(45,ratio,1,100) // Get Back to the Modelview glMatrixMode(GL_MODELVIEW) Screen Shot 54.9 Keyboard Events and Colors Example: load "freeglut.ring" load "opengl21lib.ring" 54.9. Keyboard Events and Colors 492
- 9. Ring Documentation, Release 1.5.1 angle = 0 red=1.0 blue=1.0 green=1.0 func main // init GLUT and create window glutInit() glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA) glutInitWindowPosition(100,100) glutInitWindowSize(320,320) glutCreateWindow("RingFreeGLUT - Test 6") glutDisplayFunc(:renderScene) glutReshapeFunc(:changeSize) glutIdleFunc(:renderScene) // here are the new entries glutKeyboardFunc(:processNormalKeys) glutSpecialFunc(:processSpecialKeys) glutMainLoop() func renderScene // Clear Color and Depth Buffers glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) // Reset transformations glLoadIdentity() // Set the camera gluLookAt( 0.0, 0.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0) glRotatef(angle, 0.0, 1.0, 0.0) glColor3f(red,green,blue); glBegin(GL_TRIANGLES) glVertex3f(-2.0,-2.0, 0.0) glVertex3f( 2.0, 0.0, 0.0) glVertex3f( 0.0, 2.0, 0.0) glEnd() angle+=0.1 glutSwapBuffers(); func changesize h = glutEventHeight() w = glutEventWidth() // Prevent a divide by zero, when window is too short 54.9. Keyboard Events and Colors 493
- 10. Ring Documentation, Release 1.5.1 // (you cant make a window of zero width). if (h = 0) h = 1 ok ratio = w * 1.0 / h // Use the Projection Matrix glMatrixMode(GL_PROJECTION) // Reset Matrix glLoadIdentity() // Set the viewport to be the entire window glViewport(0, 0, w, h) // Set the correct perspective. gluPerspective(45,ratio,1,100) // Get Back to the Modelview glMatrixMode(GL_MODELVIEW) func processNormalKeys key = GLUTEventKey() if key = 27 shutdown() ok func processSpecialKeys key = GLUTEventKey() switch key on GLUT_KEY_F1 red = 1.0 green = 0.0 blue = 0.0 on GLUT_KEY_F2 red = 0.0 green = 1.0 blue = 0.0 on GLUT_KEY_F3 red = 0.0 green = 0.0 blue = 1.0 off Screen Shot 54.9. Keyboard Events and Colors 494