Questions tagged [mapping]

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How is this normals map supposed to work?

I have come across this image that's labelled a bump map to be used with a 3D model. It looks like this: In this map, which is an RGB map, it seems we have pixels whose normals face upwards shaded ...
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0answers
157 views

Why do perspective correction based texture mapping do depth division

I'm currently trying to understand how works perspective correction texture mapping. I saw that actually it works by interpolating the z value of the three point of the triangle which the current ...
1
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0answers
37 views

Convex hull around polygon for cave mapping

For the purpose of mapping caves, we survey new passages so that we take main polygon (survey from point A to point B) and on each "node" (survey station A in example), we shoot multiple "splay shots" ...
2
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1answer
238 views

How do I convert a hit on an infinite plane to UV coordinates for texturing in a Raytracer?

I am trying to convert a ray hit on an infinite plane, defined by an origin and a normal vector, into UV coordinates, so I can find the appropriate texel at that point. Code I have is close to ...
1
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1answer
567 views

What is mipmapping?

I know OpenGL likes the texel resolution of textures be some power of 2 in each direction because of mipmapping. (They say that this is not a totally stringent condition, but it is preferred) Can ...
1
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1answer
293 views

Tone mapping bright images

I am rendering the sun in an image, and the sun comes out white and is basically very unrealistic. I have tried searching for tone mapping algorithms but I'm very lost. Can someone guide me to do ...
1
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1answer
63 views

I need to build my own map renderer

I have OSM world data (essentially I processed the XML data into JSON containing arrays of objects (streets, buildings etc.) that each are represented by an array of lat/lon coordinates). Some of ...
4
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1answer
40 views

Is there a term for mapping between two arbitrary quadrilaterals without using homography / perspective projection?

When warping the contents of an arbitrary quadrilateral to another by extrapolating equal points along both the "lengths" and "widths", thus ignoring all perspective effects / foreshortening, we are ...
4
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1answer
412 views

Rotation matrix for a 3D object in space

This is the follow-up question from here: Minimum requirements to uniquely represent a 3D object in space Assume I have 3 original points in a 3D object (in 3D space) as ...
4
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2answers
239 views

Minimum requirements to uniquely represent a 3D object in space

Let's assume we have a 3D object (in 3D space). We get a single representation vertex from this whole 3D object. Given the fact that the object can be moved and rotated in the space in any direction, ...
1
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1answer
136 views

Getting texture value of cartesian coordinate from a Obj file

I have an obj file together with an associated mtl file and texture jpg file. I have managed to find some code that sets a specific camera view and raytraces the image to output a depth map plus a ...
4
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2answers
454 views

Texture Mapping jagged pixel edges

I'm currently writing a software renderer. I managed to implement texture mapping and it works fine. Only issue is, that the edges between the pixels are sometimes jagged in x direction as you can see ...
7
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1answer
2k views

Perspective Correct Texture Mapping

So I'm trying to correctly map my textures in my software renderer using the u, v coordinates but I can't seem to get it working. I got affine texture mapping working. This is what I can produce using ...
5
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1answer
175 views

The Process of Spherical Harmonics

I have read about spherical harmonics from Here about the usage of SH for generating Irradiance Environment Maps and how it can make the process of generating EM faster than the regular operations. ...
10
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2answers
5k views

What is an index buffer and how is it related to vertex buffers?

I have a vertex buffer like this: 0.0, 0.0, 1.0, 0.0, 0.0, 0.6, 1.0, 0.6, 0.5, 1.0 I have the following index buffer: ...
4
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2answers
628 views

Why map Hammersley 2D set's (u,v) to sphere's (θ, φ) coordinates (and not to (φ, θ) )?

As explained in Holger Dammetz page Hammersley Points on the Hemisphere, the 2D coordinates (u,v) are usually mapped to the spherical coordinates (θ, φ). As a result, the coordinate "uniformly ...
3
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1answer
1k views

Uniform Buffers: What is quicker?

So I want to render a buttload of quads by using a single 4 point vertex array and change the position of the quad. What is quicker: Using glBufferSubData to ...
3
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1answer
4k views

What algorithm(s) are behind Google Street View's 3d mapping mode?

I recently noticed that in some locations you could switch to a 3d mapping mode in Google Street View. Which algorithm(s) did they use to generate the 3d models of the streets? I assume it was more ...