OpenGL Basics I. Seoul National University Graphics & Media Lab

Transcription

1 OpenGL Basics I Seoul National University Graphics & Media Lab

2 Contents Introduction to OpenGL OpenGL sample 01 OpenGL primitives OpenGL colors

3 Introduction to OpenGL

4 Evolution of Computers 4 Graphics and Media Lab. at Seoul National University

5 What is OpenGL? Applications Application Program HDD Windows, Unix, Mac O/S Display RAM RAM CPU GPU 5 Graphics and Media Lab. at Seoul National University

6 What is OpenGL? Applications Application Program Windows, Unix, Mac O/S GLUT HDD GLU GL Display RAM RAM CPU GPU 6 Graphics and Media Lab. at Seoul National University

7 OpenGL Capabilities 7 Graphics and Media Lab. at Seoul National University

8 OpenGL Capabilities Crytek 8 Graphics and Media Lab. at Seoul National University

9 OpenGL Capabilities Crytek 9 Graphics and Media Lab. at Seoul National University

10 Why OpenGL? Easy to learn Platform-independent OpenGL is a industry standard framework Ranging from PC to mobile system 10 Graphics and Media Lab. at Seoul National University

11 How to use OpenGL? Header files gl.h, glu.h, glut.h Library files opengl32.lib, glu32.lib, glut32.lib opengl32.dll, glu32.dll, glut32.dll opengl32.dll, glu32.dll exist in windows system folder already. (no need to copy them) 11 Graphics and Media Lab. at Seoul National University

12 How to Get GLUT? Windows opengl.org CUDA SDK (precompiled 32 and 64-bit binaries) Download freeglut source and compile it Linux Install freeglut using yum Mac Already installed 12 Graphics and Media Lab. at Seoul National University

13 Project Setting (1/10) New visual studio project. 13 Graphics and Media Lab. at Seoul National University

14 Project Setting (2/10) Select win32 console application. Specify project name & file location. 14 Graphics and Media Lab. at Seoul National University

15 Project Setting (3/10) Select empty project. 15 Graphics and Media Lab. at Seoul National University

16 Project Setting (4/10) Add new item. 16 Graphics and Media Lab. at Seoul National University

17 Project Setting (5/10) Select C++ File. Specify file name & location. 17 Graphics and Media Lab. at Seoul National University

18 Project Setting (6/10) Open project properties. 18 Graphics and Media Lab. at Seoul National University

19 Project Setting (7/10) Copy *.h,*.lib and glut32.dll to /include,/lib, and./ folders respectively. Change output directory (to use glut32.dll). 19 Graphics and Media Lab. at Seoul National University

20 Project Setting (8/10) Change include directories (to use *.h). 20 Graphics and Media Lab. at Seoul National University

21 Project Setting (9/10) Change library directories (to use *.lib). 21 Graphics and Media Lab. at Seoul National University

22 Project Setting (10/10) Add additional dependencies as follows. 22 Graphics and Media Lab. at Seoul National University

23 How to Learn More about OpenGL? The Red Book World Wide Web opengl.org nehe.gamedev.net lighthouse3d.com/opengl codeproject.com Ask Google! 23 Graphics and Media Lab. at Seoul National University

24 OpenGL sample 01 void renderscene(void) { 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();

25 Triangle / Quad Primitive glbegin(gl_triangles); glvertex3f(-0.5f, 0.5f, -5.0f); glvertex3f(-1.0f, 1.5f, -5.0f); glvertex3f(-1.5f, 0.5f, -5.0f); glend(); glbegin(gl_quads); glvertex3f(-0.7f, -1.5f, 0.0f); glvertex3f(0.7f, -1.5f, 0.0f); glvertex3f(0.4f, -0.5f, 0.0f); glvertex3f(-0.4f, -0.5f, 0.0f); glend();

26 Pentagon by Triangles glbegin(gl_triangles); //Begin triangle coordinates glvertex3f(0.5f, 1.0f, -5.0f); glvertex3f(1.5f, 1.0f, -5.0f); glvertex3f(1.0f, 1.5f, -5.0f); glvertex3f(0.5f, 1.0f, -5.0f); glvertex3f(1.5f, 0.5f, -5.0f); glvertex3f(1.5f, 1.0f, -5.0f); glvertex3f(0.5f, 0.5f, -5.0f); glvertex3f(1.5f, 0.5f, -5.0f); glvertex3f(0.5f, 1.0f, -5.0f); glend();

27 Triangle Strips glbegin(gl_triangle_strip); glvertex3f(-1.0f, -0.5f, -4.0f); glvertex3f( 1.0f, -0.5f, -4.0f); // A // B glvertex3f( 0.0f, 0.5f, -4.0f); glvertex3f( 1.5f, 0.0f, -4.0f); glvertex3f( 2.0f, -1.5f, -4.0f); // C // D // E glend();

28 Vertex Colors Set color before the vertex coordinates glcolor3f(0.5f, 0.0f, 0.8f); glbegin(gl_quads); glvertex3f(-0.7f, -0.5f, 0.0f); glvertex3f(0.7f, -0.5f, 0.0f); glvertex3f(0.4f, 0.5f, 0.0f); glvertex3f(-0.4f, 0.5f, 0.0f); glend();

29 Vertex Colors Set color before the vertex coordinates Intermediate pixel colors are computed by blending vertex colors glbegin(gl_quads); glcolor3f(0.5f, 0.0f, 0.8f); glvertex3f(-0.7f, -0.5f, 0.0f); glcolor3f(0.0f, 0.9f, 0.0f); glvertex3f(0.7f, -0.5f, 0.0f); glcolor3f(1.0f, 0.0f, 0.0f); glvertex3f(0.4f, 0.5f, 0.0f); glcolor3f(0.0f, 0.65f, 0.65f); glvertex3f(-0.4f, 0.5f, 0.0f); glend();

30 OpenGL Basics I The End

31 OpenGL Open Graphics Library Library designed for cross platform 3D graphics cf) Direct 3D: only for Microsoft Windows GLUT(The OpenGL Utility Toolkit) Making OpenGL cross-platform and simple to set up glut.h (header file) / glut32.lib (static library files) / glut32.dll (dynamic library files)