Texture Mapping Effects
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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 . -
Steep Parallax Mapping
I3D 2005 Posters Session Steep Parallax Mapping Morgan McGuire* Max McGuire Brown University Iron Lore Entertainment N E E E E True Surface I I I I Bump x P Surface P P P Parallax Mapping Steep Parallax Mapping Bump Mapping Parallax Mapping Steep Parallax Mapping Fig. 2 The viewer perceives an intersection at (P) from Fig. 1 A single polygon with a high-frequency bump map. shading, although the true intersection occurred at (I). Abstract. We propose a new bump mapping scheme that We choose t to be the first ti for which NB [ti]α > 1.0 – i / n can produce parallax, self-occlusion, and self-shadowing for and then shade as with other bump mapping methods: arbitrary bump maps yet is efficient enough for games when float step = 1.0 / n implemented in a pixel shader and uses existing data formats. vec2 dt = E.xy * bumpScale / (n * E.z) Related Work float height = 1.0; Let E and L be unit vectors from the eye and light in a local vec2 t = texCoord.xy; vec4 nb = texture2DLod (NB, t, LOD); tangent space. At a pixel, let 2-vector s be the texture coordinate (i.e. where the eye ray hits the true, flat surface) while (nb.a < height) { and t be the coordinate of the texel where the ray would have height -= step; t += dt; nb = texture2DLod (NB, t, LOD); hit the surface if it were actually displaced by the bump map. } Shading is computed by Phong illumination, using the // ... Shade using N = nb.rgb normal to the scalar bump map surface B at t and the color of the texture map at t. -
Texture Mapping
Texture Mapping Slides from Rosalee Wolfe DePaul University http://www.siggraph.org/education/materials/HyperGraph/mapping/r_wolf e/r_wolfe_mapping_1.htm 1 1. Mapping techniques add realism and interest to computer graphics images. Texture mapping applies a pattern of color to an object. Bump mapping alters the surface of an object so that it appears rough, dented or pitted. In this example, the umbrella, background, beachball and beach blanket have texture maps. The sand has been bump mapped. These and other mapping techniques are the subject of this slide set. 2 2: When creating image detail, it is cheaper to employ mapping techniques that it is to use myriads of tiny polygons. The image on the right portrays a brick wall, a lawn and the sky. In actuality the wall was modeled as a rectangular solid, and the lawn and the sky were created from rectangles. The entire image contains eight polygons.Imagine the number of polygon it would require to model the blades of grass in the lawn! Texture mapping creates the appearance of grass without the cost of rendering thousands of polygons. 3 3: Knowing the difference between world coordinates and object coordinates is important when using mapping techniques. In object coordinates the origin and coordinate axes remain fixed relative to an object no matter how the object’s position and orientation change. Most mapping techniques use object coordinates. Normally, if a teapot’s spout is painted yellow, the spout should remain yellow as the teapot flies and tumbles through space. When using world coordinates, the pattern shifts on the object as the object moves through space. -
Advanced Texture Mapping
Advanced texture mapping Computer Graphics COMP 770 (236) Spring 2007 Instructor: Brandon Lloyd 2/21/07 1 From last time… ■ Physically based illumination models ■ Cook-Torrance illumination model ° Microfacets ° Geometry term ° Fresnel reflection ■ Radiance and irradiance ■ BRDFs 2/21/07 2 Today’s topics ■ Texture coordinates ■ Uses of texture maps ° reflectance and other surface parameters ° lighting ° geometry ■ Solid textures 2/21/07 3 Uses of texture maps ■ Texture maps are used to add complexity to a scene ■ Easier to paint or capture an image than geometry ■ model reflectance ° attach a texture map to a parameter ■ model light ° environment maps ° light maps ■ model geometry ° bump maps ° normal maps ° displacement maps ° opacity maps and billboards 2/21/07 4 Specifying texture coordinates ■ Texture coordinates needed at every vertex ■ Hard to specify by hand ■ Difficult to wrap a 2D texture around a 3D object from Physically-based Rendering 2/21/07 5 Planar mapping ■ Compute texture coordinates at each vertex by projecting the map coordinates onto the model 2/21/07 6 Cylindrical mapping 2/21/07 7 Spherical mapping 2/21/07 8 Cube mapping 2/21/07 9 “Unwrapping” the model 2/21/07 images from www.eurecom.fr/~image/Clonage/geometric2.html 10 Modelling surface properties ■ Can use a texture to supply any parameter of the illumination model ° ambient, diffuse, and specular color ° specular exponent ° roughness fr o m ww w.r o nfr a zier.net 2/21/07 11 Modelling lighting ■ Light maps ° supply the lighting directly ° good for static environments -
Visualizing 3D Objects with Fine-Grain Surface Depth Roi Mendez Fernandez
Visualizing 3D models with fine-grain surface depth Author: Roi Méndez Fernández Supervisors: Isabel Navazo (UPC) Roger Hubbold (University of Manchester) _________________________________________________________________________Index Index 1. Introduction ..................................................................................................................... 7 2. Main goal .......................................................................................................................... 9 3. Depth hallucination ........................................................................................................ 11 3.1. Background ............................................................................................................. 11 3.2. Output .................................................................................................................... 14 4. Displacement mapping .................................................................................................. 15 4.1. Background ............................................................................................................. 15 4.1.1. Non-iterative methods ................................................................................... 17 a. Bump mapping ...................................................................................... 17 b. Parallax mapping ................................................................................... 18 c. Parallax mapping with offset limiting ................................................... -
Towards a Set of Techniques to Implement Bump Mapping
Towards a set of techniques to implement Bump Mapping Márcio da Silva Camilo, Bernardo Nogueira S. Hodge, Rodrigo Pereira Martins, Alexandre Sztajnberg Departamento de Informática e Ciências da Computação Universidade Estadual do Rio de Janeiro {pmacstronger, bernardohodge , rodrigomartins , alexszt}@ime.uerj.br Abstract . irregular lighting appearance without modeling its irregular patterns as true geometric perturbations, The revolution of three dimensional video games increasing the model’s polygon count, hence decreasing lead to an intense development of graphical techniques applications’ performance. and hardware. Texture-mapping hardware is now able to There are several other techniques for generate interactive computer-generated imagery with implementing bump mapping. Some of them, such as high levels of per-pixel detail. Nevertheless, traditional Emboss Mapping, do not result in a good appearance for single texture techniques are not able to simulate bumped some surfaces, in general because they use a too simplistic surfaces decently. More traditional bump mapping approximation of light calculation [4]. Others, such as techniques, such as Emboss bump mapping, most times Blinn’s original bump mapping idea, are computationally deploy an undesirable or ‘fake’ appearance to wrinkles in expensive to calculate in real-time [7]. Dot3 bump surfaces. Bump mapping can be applied to different types mapping deploys a great final result on surface appearance of applications varying form computer games, 3d and is feasible in today’s hardware in a single rendering environment simulations, and architectural projects, pass. It is based on a mathematical model of lighting among others. In this paper we will examine a method that intensity and reflection calculated for each pixel on a can be applied in 3d game engines, which uses texture- surface to be rendered. -
Texture Mapping Objectives the Limits of Geometric Modeling
Objectives •Introduce Mapping Methods Texture Mapping - Texture Mapping - Environment Mapping - Bump Mapping CS 432 Interactive Computer Graphics •Consider basic strategies Prof. David E. Breen - Forward vs backward mapping Department of Computer Science - Point sampling vs area averaging E. Angel and D. Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 1 E. Angel and D. Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 2 1 2 The Limits of Geometric Modeling an Orange Modeling •Although graphics cards can render over •Consider the problem of modeling an orange 20 million polygons per second, that (the fruit) number is insufficient for many phenomena •Start with an orange-colored sphere - Clouds - Too simple - Grass •Replace sphere with a more complex shape - Terrain - Does not capture surface characteristics (small - Skin dimples) - Takes too many polygons to model all the dimples E. Angel and D. Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 3 E. Angel and D. Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 4 3 4 Modeling an Orange (2) Three Types of Mapping •Take a picture of a real orange, scan it, •Texture Mapping and “paste” onto simple geometric model - Uses images to fill inside of polygons - This process is known as texture mapping •Environment (reflection mapping) •Still might not be sufficient because - Uses a picture of the environment for texture resulting surface will be smooth maps - Need to change local shape - Allows simulation of highly specular surfaces - Bump mapping •Bump mapping - Emulates altering normal vectors during the rendering process E. Angel and D. Shreiner: Interactive Computer Graphics 6E © Addison-Wesley 2012 5 E. -
INTEGRATING PIXOLOGIC ZBRUSH INTO an AUTODESK MAYA PIPELINE Micah Guy Clemson University, [email protected]
Clemson University TigerPrints All Theses Theses 8-2011 INTEGRATING PIXOLOGIC ZBRUSH INTO AN AUTODESK MAYA PIPELINE Micah Guy Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Part of the Computer Sciences Commons Recommended Citation Guy, Micah, "INTEGRATING PIXOLOGIC ZBRUSH INTO AN AUTODESK MAYA PIPELINE" (2011). All Theses. 1173. https://tigerprints.clemson.edu/all_theses/1173 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. INTEGRATING PIXOLOGIC ZBRUSH INTO AN AUTODESK MAYA PIPELINE A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Fine Arts in Digital Production Arts by Micah Carter Richardson Guy August 2011 Accepted by: Dr. Timothy Davis, Committee Chair Dr. Donald House Michael Vatalaro ABSTRACT The purpose of this thesis is to integrate the use of the relatively new volumetric pixel program, Pixologic ZBrush, into an Autodesk Maya project pipeline. As ZBrush is quickly becoming the industry standard in advanced character design in both film and video game work, the goal is to create a succinct and effective way for Maya users to utilize ZBrush files. Furthermore, this project aims to produce a final film of both valid artistic and academic merit. The resulting work produced a guide that followed a Maya-created film project where ZBrush was utilized in the creation of the character models, as well as noting the most useful formats and resolutions with which to approach each file. -
Digital Lighting and Rendering
[digital] LIGHTING & RENDERING Third Edition Jeremy Birn Digital Lighting and Rendering, Third Edition Jeremy Birn New Riders www.newriders.com To report errors, please send a note to [email protected] New Riders is an imprint of Peachpit, a division of Pearson Education. Copyright © 2014 Jeremy Birn Senior Editor: Karyn Johnson Developmental Editor: Corbin Collins Copyeditor: Rebecca Rider Technical Editor: Shawn Nelson Production Editor: David VanNess Proofreader: Emily K. Wolman Composition: Maureen Forys, Happenstance Type-O-Rama Indexer: Jack Lewis Interior design: Maureen Forys, Happenstance Type-O-Rama Cover design: Charlene Charles-Will Notice of Rights All rights reserved. No part of this book may be reproduced or transmitted in any form by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. For information on getting permission for reprints and excerpts, contact [email protected]. Notice of Liability The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation of the book, neither the author nor Peachpit shall have any liability to any person or entity with respect to any loss or dam- age caused or alleged to be caused directly or indirectly by the instructions contained in this book or by the computer software and hardware products described in it. Trademarks Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and Peachpit was aware of a trademark claim, the designations appear as requested by the owner of the trademark. -
Real-Time Recursive Specular Reflections on Planar and Curved Surfaces Using Graphics Hardware
REAL-TIME RECURSIVE SPECULAR REFLECTIONS ON PLANAR AND CURVED SURFACES USING GRAPHICS HARDWARE Kasper Høy Nielsen Niels Jørgen Christensen Informatics and Mathematical Modelling The Technical University of Denmark DK 2800 Lyngby, Denmark {khn,njc}@imm.dtu.dk ABSTRACT Real-time rendering of recursive reflections have previously been done using different techniques. How- ever, a fast unified approach for capturing recursive reflections on both planar and curved surfaces, as well as glossy reflections and interreflections between such primitives, have not been described. This paper describes a framework for efficient simulation of recursive specular reflections in scenes containing both planar and curved surfaces. We describe and compare two methods that utilize texture mapping and en- vironment mapping, while having reasonable memory requirements. The methods are texture-based to allow for the simulation of glossy reflections using image-filtering. We show that the methods can render recursive reflections in static and dynamic scenes in real-time on current consumer graphics hardware. The methods make it possible to obtain a realism close to ray traced images at interactive frame rates. Keywords: Real-time rendering, recursive specular reflections, texture, environment mapping. 1 INTRODUCTION mapped surface sees the exact same surroundings re- gardless of its position. Static precalculated environ- Mirror-like reflections are known from ray tracing, ment maps can be used to create the notion of reflec- where shiny objects seem to reflect the surrounding tion on shiny objects. However, for modelling reflec- environment. Rays are continuously traced through tions similar to ray tracing, reflections should capture the scene by following reflected rays recursively un- the actual synthetic environment as accurately as pos- til a certain depth is reached, thereby capturing both sible, while still being feasible for interactive render- reflections and interreflections. -
LEAN Mapping
LEAN Mapping Marc Olano∗ Dan Bakery Firaxis Games Firaxis Games (a) (b) (c) Figure 1: In-game views of a two-layer LEAN map ocean with sun just off screen to the right, and artist-selected shininess equivalent to a Blinn-Phong specular exponent of 13,777: (a) near, (b) mid, and (c) far. Note the lack of aliasing, even with an extremely high power. Abstract 1 Introduction For over thirty years, bump mapping has been an effective method We introduce Linear Efficient Antialiased Normal (LEAN) Map- for adding apparent detail to a surface [Blinn 1978]. We use the ping, a method for real-time filtering of specular highlights in bump term bump mapping to refer to both the original height texture that and normal maps. The method evaluates bumps as part of a shading defines surface normal perturbation for shading, and the more com- computation in the tangent space of the polygonal surface rather mon and general normal mapping, where the texture holds the ac- than in the tangent space of the individual bumps. By operat- tual surface normal. These methods are extremely common in video ing in a common tangent space, we are able to store information games, where the additional surface detail allows a rich visual ex- on the distribution of bump normals in a linearly-filterable form perience without complex high-polygon models. compatible with standard MIP and anisotropic filtering hardware. The necessary textures can be computed in a preprocess or gener- Unfortunately, bump mapping has serious drawbacks with filtering ated in real-time on the GPU for time-varying normal maps. -
Texture Mapping
Texture Mapping University of Texas at Austin CS384G - Computer Graphics Fall 2010 Don Fussell Reading Required Watt, intro to Chapter 8 and intros to 8.1, 8.4, 8.6, 8.8. Recommended Paul S. Heckbert. Survey of texture mapping. IEEE Computer Graphics and Applications 6(11): 56--67, November 1986. Optional Watt, the rest of Chapter 8 Woo, Neider, & Davis, Chapter 9 James F. Blinn and Martin E. Newell. Texture and reflection in computer generated images. Communications of the ACM 19(10): 542--547, October 1976. University of Texas at Austin CS384G - Computer Graphics Fall 2010 Don Fussell 2 What adds visual realism? Geometry only Phong shading Phong shading + Texture maps University of Texas at Austin CS384G - Computer Graphics Fall 2010 Don Fussell 3 Texture mapping Texture mapping (Woo et al., fig. 9-1) Texture mapping allows you to take a simple polygon and give it the appearance of something much more complex. Due to Ed Catmull, PhD thesis, 1974 Refined by Blinn & Newell, 1976 Texture mapping ensures that “all the right things” happen as a textured polygon is transformed and rendered. University of Texas at Austin CS384G - Computer Graphics Fall 2010 Don Fussell 4 Non-parametric texture mapping With “non-parametric texture mapping”: Texture size and orientation are fixed They are unrelated to size and orientation of polygon Gives cookie-cutter effect University of Texas at Austin CS384G - Computer Graphics Fall 2010 Don Fussell 5 Parametric texture mapping With “parametric texture mapping,” texture size and orientation are tied to the