Bump Mapping: Exploring Depth in Computer Vision

By Fouad Sabry

What is Bump Mapping

Creating the appearance of bumps and wrinkles on the surface of an object is the goal of the texture mapping technique known as bump mapping, which is used in computer graphics. This can be accomplished by perturbing the surface normals of the object and then using the disturbed normal in the calculations that are performed for the illumination. The end result is a surface that appears to be bumpy rather than smooth, despite the fact that the surface of the object that is now being worked on remains unchanged. In 1978, James Blinn laid the groundwork for the concept of bump mapping.

How you will benefit

(I) Insights, and validations about the following topics:

Chapter 1: Bump mapping

Chapter 2: Texture mapping

Chapter 3: Normal mapping

Chapter 4: Per-pixel lighting

Chapter 5: Heightmap

Chapter 6: Self-shadowing

Chapter 7: Displacement mapping

Chapter 8: Collision detection

Chapter 9: Gouraud shading

Chapter 10: Phong shading

(II) Answering the public top questions about bump mapping.

(III) Real world examples for the usage of bump mapping in many fields.

Who this book is for

Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of Bump Mapping.

• Language: English
• Publisher: One Billion Knowledgeable
• Release date: May 5, 2024

Book preview

Chapter 1: Bump mapping

Bump mapping

Normal mapping is the most prevalent type of bump mapping.

Bump mapping is a technique in computer graphics that simulates minor surface displacements to make a displayed surface appear more realistic. Unlike displacement mapping, however, the surface geometry is not altered. Instead, only the surface normal is tweaked to simulate a displacement. The changed surface normal is then used for lighting computations (using, for instance, the Phong reflection model), resulting in a surface that seems detailed as opposed to smooth.

Bump mapping is significantly faster and uses fewer resources than displacement mapping for the same degree of detail because the geometry remains unaltered.

In addition to enhancing the sensation of depth, there are extensions that alter other surface characteristics. Horizon mapping and parallax mapping are two of these extensions. Therefore, silhouettes and shadows are unchanged, which is particularly apparent for larger simulated displacements. This constraint can be circumvented through the use of techniques such as displacement mapping in which bumps are placed to the surface or an isosurface.

There are two basic bump mapping techniques. The first method simulates surface displacement using a height map, resulting in a changed normal. This is the technique developed by Blinn and is typically referred to as bump mapping unless otherwise indicated. This method's steps are summarized as follows.

Before a lighting calculation is conducted for every visible point (or pixel) on an object's surface, the object's surface is mapped:

Consult the height in the heightmap that corresponds to the surface location.

Calculate the heightmap's surface normal, often using the finite difference method.

Combine the second-step surface normal with the genuine (geometric) surface normal so that the combined normal points in a different direction.

Calculate the interaction between the new bumpy surface and scene lights using a model such as the Phong reflection model.

As a result, the surface appears to have actual depth. The program also ensures that the surface appearance changes as the scene's lighting is manipulated.

The alternative way is to specify a normal map with the updated normal for each surface point. Since the normal is supplied directly as opposed to being calculated from a height map, this technique typically yields more predictable outcomes. This simplifies the process for artists, making it the most prevalent way of bump mapping today.

Realtime 3D graphics programmers frequently employ variants of the approach to replicate bump mapping at a reduced computational cost.

A popular method consisted of utilizing a fixed geometry, which permits the application of the heightmap surface normal practically directly. In conjunction with a precomputed lookup table for lighting calculations, the method might be implemented with a very simple and quick loop, allowing for full-screen effects. This technique was prevalent when bump mapping was first developed.

{End Chapter 1}

Chapter 2: Texture mapping

Texture mapping is a technique used to map a texture onto a computer-generated image. Texture might be high frequency detail, surface texture, or color in this context.

In 1974, Edwin Catmull developed the first version of the method.

Texture mapping initially referred to diffuse mapping, a method that simply mapped a texture's pixels onto a 3D surface (wrapping the image around the object). In recent decades, the advent of multi-pass rendering, multitexturing, mipmaps, and more complex mappings such as height mapping, bump mapping, normal mapping, displacement mapping, reflection mapping, specular mapping, occlusion mapping, and many variations of the technique (controlled by a materials system) have made it possible to simulate near-photorealism in real time by drastically reducing the number of polygons and lighting calculations required to build a scene.

A surface map This could be either a bitmap or a generated texture. They can be saved in standard picture file formats, referenced by 3D model formats or material descriptions, and bundled into resource bundles.

Visible surfaces may have 1-3 dimensions, although two dimensions are most common. Texture map data may be stored in shuffled or tiled orders to increase cache coherence when used