Vzorová Prezentace Dcgi
Textures Jiří Bittner, Vlastimil Havran Textures . Motivation - What are textures good for? MPG 13 . Texture mapping principles . Using textures in rendering . Summary 2 Textures Add Details 3 Cheap Way of Increasing Visual Quality 4 Textures - Introduction . Surface macrostructure . Sub tasks: - Texture definition: image, function, … - Texture mapping • positioning the texture on object (assigning texture coordinates) - Texture rendering • what is influenced by texture (modulating color, reflection, shape) 5 Typical Use of (2D) Texture . Texture coordinates (u,v) in range [0-1]2 u brick wall texel color v (x,y,z) (u,v) texture spatial parametric image coordinates coordinates coordinates 6 Texture Data Source . Image - Data matrix - Possibly compressed . Procedural - Simple functions (checkerboard, hatching) - Noise functions - Specific models (marvle, wood, car paint) 8 Texture Dimension . 2D – images . 1D – transfer function (e.g. color of heightfield) . 3D – material from which model is manufactured (wood, marble, …) - Hypertexture – 3D model of partly transparent materials (smoke, hair, fire) . +Time – animated textures 9 Texture Data . Scalar values - weight, intensity, … . Vectors - color - spectral color 10 Textures . Motivation - What are textures good for? MPG 13 . Texture mapping principles . Using textures in rendering . Summary 11 Texture Mapping Principle Texture application Planar Mapping texture 2D image to 3D surface (Inverse) texture mapping T: [u v] –> Color M: [x y z] –> [u v] M ◦ T: [x y z] –> [u v] –> Color 12 Texture Mapping – Basic Principles . Inverse mapping . Geometric mapping using proxy surface . Environment mapping 13 Inverse Texture Mapping – Simple Shapes . sphere, toroid, cube, cone, cylinder T(u,v) (M ◦ T) (x,y,z) v z v y u u x z z [x, y, z] r r h y β α y x x [u,v]=[0,0.5] [u,v]=[0,0] 14 Texture Mapping using Proxy Surface .
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