Surface Rendering With OpenGL

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Surface Rendering With OpenGL

• CS460 Project
• by Rui Yu
• 11/30/03

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Two aspects

• Windowing system or user interface
• Use MFC
• Create a window
• Viewport is the client area of the window
• Capture mouse move events in the client area
• Add buttons on a tools bar
• OpenGL commands
• Use gl,glu fuctions
• Viewing pipeline
• Surface rendering

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Viewing pipeline

• ChoosePixelFormat // Define pixel format
• wglCreateContext //Create rendering
  context.
• glMatrixMode(GL_MODELVIEW)
• glRotatef //rotate
• glScalef //scale
• glMatrixMode(GL_PROJECTION)
• glOrtho(-1,1,-1,1,-1,1) //Parellel
  projection
• glViewport(0, 0, cx, cy)
• glBegin(GL_LINES) //or GL_POLYGON and etc.
• glVertex3d
• glVertex3d
• glEnd
• SwapBuffers

3D modeling coordinates
Modeling transformation
3D world coordinates
Clipping projection
Transform into viewport
2D device coordinates
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Example

• Pixel Format DOUBLE BUFFER, RGBA, DRAW_TO_WINDOW
• View volume

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Screen Shots (1)-draw 3D points interactively
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Screen Shots (2)-draw 3D bezier surface with
zoom and rotation
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Shading

• The Mathematics of Lighting
• vertex color
• global ambient light ambient material
• ?i attenuation factor Ii
• ambient light ambient material
• (max 1 x n , 0 ) diffuse light diffuse
  material
• (max s x n ,0 )shininess specular light
  specular material
• l the unit vector that points from the vertex
  to the light position
• n the unit normal vector at the vertex.
• Default Lighting Value
• Global Ambient Light 0.2, 0.2, 0.2, 1.0

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Table1 Default Values for glLight0()
Table2 Default Values for glMaterial()
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Screen Shots (3)-Change light intensity and
material property (1)
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Screen Shots (4)-Change light intensity and
material property (2)
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Screen Shots (5)-Drag control points of bezier
surface and texture mapping (1)
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Screen Shots (6)-Drag control points of bezier
surface and texture mapping (2)
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bibliography

• Msdn
• http//www.msdn.com
• OpenGL Programming Guide or 'The Red Book from
  Silicon Graphics, Inc
• Guide to OpenGL on Windows from Silicon Graphics
• http//www.opengl.org/developers/documentation/ove
  rviews.html
• OpenGL Win32 Tutorial
• http//www.nullterminator.net/opengl32.html
• http//www.opengl.org/developers/code/tutorials.ht
  ml
• Basic Curves And Surfaces Modeler by Sharjith
• http//www.codeproject.com/useritems/cadsurf.asp