ENVIRONMENT MAPPING

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ENVIRONMENT MAPPING
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INTRODUCTION

• What is environment mapping?
• Parameterization
• Prefiltering Phong Model
• Fresnel Term
• Environment mapped bump mapping
• Environment mapping with OpenGL

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What is environment mapping?
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What is environment mapping?

• Developed by Blinn and Newell (1976)
• Reflecting the surroundings on an object
• Describes the incoming or outgoing light
• Objects can not reflect themselves
• Another problem is distortion
• Cube mapping, spherical mapping,
• parabolic mapping

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What is environment mapping?
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Parameterization

• Directions
• Texture coordinates

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Parameterization

• No recreation of the map for every frame
• Easy creation of the map
• Easy calculation of texture coordinates

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Parameterization

• Spherical
• Cubic
• Parabolic

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Sphere Maps
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Sphere Maps
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Sphere Maps
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Sphere Maps
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Sphere Maps

• Disadvantages
• Only suitable for original viewing direction
• Doesnt reflect changes in the scene

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Sphere Maps
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Sphere Maps

• Disadvantages
• Only suitable for original viewing direction
• Doesnt reflect changes in the scene

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Parameterization

• Spherical
• Cubic
• Parabolic

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Cube Maps

• Advantages
• No warping step required
• Viewpoint independent

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Cube Maps
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Cube Maps
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Cube Maps
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Parameterization

• Spherical
• Cubic
• Parabolic

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Parabolic Maps
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Phong Model

• Linear combination of 3 components
• Diffuse
• Ambient
• Specular

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Phong Model
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Phong Model
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Fresnel Term
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Fresnel Term

• Reflectivity of a material depending on its
  optical density and angle of the incoming light.
• For metallic surfaces the incoming illumination
  outgoing illumination.
• For non-metallic surfaces the angle of incoming
  light is important.

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Fresnel Term
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Fresnel Term
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Environment mapped bump mapping (EMBM)

• Objects get more details
• Is a possibility to represent plastically objects
• Three different textures

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Three different textures

• 1.Base
• texture
• 2.Bump
• map
• 3.Environment
• map

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Environment mapped bump mapping (EMBM)
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Environment mapped bump mapping (EMBM)

• Bump mapping with a light map
• Real environmental bump mapping

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Bump mapping with a light map
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Environment mapped bump mapping (EMBM)

• Bump mapping with a light map
• Real environmental bump mapping

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Real environmental bump mapping
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Environment mapped bump mapping (EMBM)

• Same effects with cube environment maps possible
• Makes environment mapping possible in all
  directions
• Non-cube environment mapped bump mapping is
  limited to few directions

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OpenGL sphere mapping

• Four steps
• Create texture
• Define texture generation
• Enable texture coordinate generation
• Draw object

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OpenGL Cube mapping

• New extension Ext_texture_cube_map
• Six images
• Quadratic images
• glCopySubTexImage2D

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The End
Thank you, for your attention !!