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After making any 3D model using Opengl how to export it's data in .dae file?

I'm trying to make simple 3d modeling program in c++ with Opengl. So I don't know how to transfer/convert/export or save data of 3D model in .dae file. NOTE:- 3d model is made using Opengl ...
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0answers
18 views

Projecting one Quadratic Bezier Curve Onto Another

I'm working on improving an open source rasterization library called Gudni that I started a few years ago. It's source repository and the branch I'm currently working on are here: https://github.com/...
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1answer
43 views

Confusion around Lambert's Cosine Law in Ray Tracing in One Weekend

Peter Shirely's Ray Tracing in One Weekend presents the following function to calculate the color of a lambertian material (See chapter's 7 and 8): ...
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0answers
30 views

Distribution of the first vertex on a camera subpath in bidirectional path tracing

Suppose we are sampling camera rays of a perspective camera with a finite aperture. The PBRT implementation of the sampling scheme looks like this: ...
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1answer
29 views

What kind of transformation when the aspect is changed for a rotated shape?

I have a geometric shape (assuming that is a rectangle). I want to rotate it about it geometric center by an angle of 45° and plot the result using matplotlib with an equal aspect ratio, I get ...
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19 views

Computing probabilties when connecting a camera subpath to a single light point

I'm struggling to understand how the connection step in bidirectional path tracing for the strategy with a single light vertex has to be implemented. The following code essentially shows the PBRT ...
2
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0answers
26 views

Multipass Rendering Vertex Buffer Organisation

I am working on a Renderer that should do a Depth Prepass before rendering the desired geometry. For this I have a Vertex and Pixel Shader that outputs to the Depth Texture. After that it should ...
1
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0answers
40 views

What other geometry processing data structures are there?

I essentially know of 2 geometry processing data structures. one is the half edge (which has some really nice properties, but can't represent non manifold meshes nor tet meshes). The other is an ...
1
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0answers
25 views

Intrinsic Matrix vs Perspective projection matrix

I was going through the camera matrix explained in the wikipedia article and understand how the matrix K \begin{bmatrix}f_x&s&x_0\\0&f_y&y_0\\0&0&1\end{bmatrix} is built. The ...
2
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0answers
35 views
+50

Chart swaps and path inversion in bidirectional path tracing

I've got a hard time to understand how we would implement the following in practice. I'd be great if someone could explain the details for the example below. Assume we're generating a path ${\rm x}=(\...
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0answers
22 views

Inverse path sampling in (bidirectional) path tracing

In Section 4.1 of the paper Fusing State Spaces for Markov Chain Monte Carlo Rendering, it is described that the CDF $P$ of the distribution of paths of length $k\in\mathbb N$ may be factored into a ...
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0answers
33 views

Problems with Cascaded Shadow Maps

I got basic shadow mapping with a single directional light working in a small voxel game I'm working on, and I've been trying to upgrade it to Cascaded Shadow Maps. I've looked at a few tutorials - ...
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0answers
15 views

Computing inverses in Reversible-Jump Metropolis Light Transport

Say we are sampling a path $\rm x=(\rm x_0,\ldots,\rm x_{n-1})$ of length $n-1$ using bidirectional path tracing. Let $p_s$ denote the area product density corresponding to the used connection ...
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0answers
53 views

Ray Tracing -Weird Edge Artifact

I am interested in Path Tracing, I currently follow the Ray Tracing in a weekend book. When implementing the metal material, I get a strange artifact on the edge of the sphere that does not appear in ...
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1answer
58 views

Retrieve real distance from depth buffer for shadow ray (vulkan hybrid rendering)

I'm trying to implement an hybrid renderer based on Vulkan extension VK_NV_ray_tracing. Basically, the rasterizer compute the albedo and depth map of the scene. Then I try to compute the distance from ...
1
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1answer
43 views

In bidirectional path tracing, is a camera subpath with $n$ vertices determined by a fixed number of random numbers?

In the Multiplexed Metropolis Light Transport implementation of the book Physically Based Rendering, the proposal samples are generated by the Primary Sample Space Sampler ...
3
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1answer
53 views

Saving a mesh and textures into a single file

I'm looking for a format where I could store a triangle mesh and multiple textures into a single file. Most formats only reference an external file for textures. I found that the FBX format should ...
0
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2answers
104 views

Why is my raycaster so slow?

I'm trying to write a raycaster similar to Voxlap, but it's many times slower. I've tried octrees, but the performance gains are marginal- only 10 to 20 percent. I use the algorithm from this site: ...
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0answers
43 views

Estimate 3D cube pose after camera rotation

I have some photos of 3D cube. I also know the 3D pose of the cube in each photo (yaw, pitch, roll). I want to estimate the new pose (yaw, pitch, roll) of the cube after performing 2D rotation to the ...
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0answers
31 views

Bounding box of a rotating mesh

I compute bounding box of a mesh: (xMin, xMax) (yMin, yMax) (zMin, zMax) To get the bounding box, I need to go through all the mesh points and compute the min/...
1
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0answers
47 views

GPU Procedural placement - Creating evenly distributed sampling points

I am working on a procedural placement system on the GPU, inspired by the work done by Guerrilla Games in Horizon Zero Dawn: https://www.guerrilla-games.com/read/gpu-based-procedural-placement-in-...
-1
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0answers
42 views

Books on topic OpenGL in software developing

Maybe it's a duplicated question but I haven't found anything similar. So, I've recently started to learn OpenGL using sites like learnopengl.com, which gave me a brief and nice explanation on how to ...
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1answer
16 views

Standard ways to create xml scenes for research purposes

I am a newbie in computer graphics and just started working on physically based rendering engines such as Mitsuba. I found it difficult to create my own scenes, that are xml files. To create one, ...
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1answer
38 views

Understanding the near clipping plane

I don't understand something about the near clipping plane. It's there to avoid the division by $0$ but when we compute the pixel coordinates, we just need to multiply by the clipping plane to clip ...
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0answers
61 views

How to pack 3 floats into one?

I am doing some animation jobs. I need to pack some pivots into UV and then my shader can read them. I need to pack 4 float3 into a float4. Therefore, I need to pack each float3 into a float. ...
3
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1answer
47 views

Intrepret path/light tracing by rewriting light transport equation

Given the rendering equation: $$ L_o(x, \theta_o) = L_e(x, \theta_o) + \int_{\Omega} \! f(x,\theta_i,\theta_o) L_i(x,\theta_i) \cos(\theta_i, \theta_o) \, \mathrm{d} \theta_i. $$ Rewriting it using ...
1
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0answers
58 views

BSP tree rendering

As a little project, I'd like to implement a BSP merging algorithm for Boolean operations on solids. But to even tell whether it works, I need some way to render the BSP tree. In other words, I have a ...
1
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1answer
33 views

Vulkan: using gl_PrimitiveID without geometryShader feature

When compiling a glsl fragment shader which reads gl_PrimitiveID with glslc compiler I get the spirv-1.0 with Geometry capability enabled, which is technically ...
0
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2answers
137 views

What are “Triangles” in 3d modeling?

In 3d modeling, there is some "triangle count" which determines complexity. I am not sure but I think cubes have 12 triangles or somethong.But I see NONE They have squares, no triangles! Can someone ...
1
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0answers
27 views

How to programmatically extract shape types like circle etc from SVG file path attributes

I have paths in SVG file with d attributes with values like M 48.75521890547264 45.77014427860697 Q 48.756218905472636 45.77114427860697 50.24875621890547 45....
4
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1answer
131 views

What is a “light source” in global illumination?

In the context of global illumination and the scattering equation, do we need to understand "light sources" as surfaces with a "purely emissive" material on which no scattering is present? In ...
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0answers
39 views

Implementation of the Primary Sample Space Sampler in the book Primary Sample Space Sampler

In the Multiplexed Metropolis Light Transport implementation of the book Physically Based Rendering, the proposal samples are generated by the Primary Sample Space Sampler ...
2
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0answers
29 views

Project a Square as rectangle in projection plane using perspective projection

Consider a square S with vertices (1,1,0), (1,-1,0), (-1,-1,0) and (-1,1,0) and a plane P defined by $z=1$. Let the perspective projection of S on P is denoted by S'. What coordinates of the Center ...
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0answers
13 views

What would be an example of decoding-intensive video?

my question might come in a bit weird but I'm looking for something that would be considered very CPU-intensive video to decode (for playback I mean). I would like to have some sample of 1080p and 4k ...
2
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0answers
36 views

When should operations on 4D (homogeneous/projective) vectors use the w-coordinate?

Various operations on 2D vectors naturally generalise to 3D vectors simply by including the $z$-coordinate. The ones that come to mind are: Vector sum and difference Dot product Magnitude (Euclidean ...
1
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1answer
67 views

What is the point of having integer-based draw routines in software rasterizer?

I wonder why all the well known algorithms of drawing for example circles (bresenham, mid-point, etc) all use integer arithmetics? For example, here is a simple circle drawn with bresenham algorithm: ...
0
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1answer
27 views

Generating the end caps of a cylinder using triangle strips for use in a geometry shader

I know how to generate the walls of a cylinder with triangle strips and the caps with triangle fans, but since I am working inside a geometry shader, I can only output triangle strips, so I am kind of ...
3
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1answer
57 views

Shader or formula that distorts inward

I am looking for a shader (or at least the right terminology) for crushing an image. It should be something very similar to barrel distortion, but instead of the center crushing outward to the edges, ...
0
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0answers
19 views

How do I render from chunks?

I'm trying to implement chunks/octrees to speed up my rendering times. However, objects sometimes disappear, and it segfaults or hangs frequently. Full code: https://pastebin.com/4P3sX6BV - main....
0
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1answer
34 views

Mapping sample to a disk

So I have been reading this wonderful book on ray tracing by Kevin Suffern, Ray tracing from Ground Up. I am reading this book after finishing Peter Shirley's first two book on ray tracing & ...
0
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1answer
44 views

Trouble making path tracer multithreaded, read access violation

I'm trying to make the path tracer shown in the Ray Tracing in One Weekend series multithreaded. Here's the starting of my main function: ...
2
votes
1answer
69 views

How can I raycast with chunks?

I am attempting to implement chunks/octrees to speed up my render times. However, sometimes the walls show horizontal or vertical lines (rays hitting the inside of voxels?) or some blocks disappear ...
0
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0answers
25 views

Can solid voxelization be done with 1-direction raytracing if the raytracer is watertight? Does the direction matter?

This article and some others mention requiring the following when voxelizing: 1: Shooting rays from multiple directions (maybe with a voting system to decide if the voxel is active?) 2: Shooting ...
0
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0answers
30 views

Transformation for aligning 3D object with reference frame of 3D turtle graphics

The problem I'm using a 3D extension of the well-known "Turtle graphics" to draw plants. My system works by maintaining a position $\vec{p}$ and three vectors: The heading $\vec{H}$ The "up" ...
2
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1answer
122 views

Implementing the example of Walter et al. (2007) paper

As the title suggests I'm trying to implement the last images of the "Microfacet Models for Refraction through Rough Surfaces" Paper by Walter et al. in OpenGL I "think" (I had to put that into ...
1
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0answers
41 views

Convert a polygon mesh to a bspline surface

Problem: Getting a polygon mesh as input, I have to construct a surface that looks exactly to the given input. My task is to generate a b-spline surface that exactly looks like the connected polygon ...
0
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1answer
58 views

Trouble using Open Image Denoise

I'm trying to use open image denoise. Here's the code: ...
1
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0answers
40 views

How to Pan Zoom a spherical camera?

I asked this in regular SO but I think people are not understanding the question so i will try here: So, for anyone familiar with Google Maps, when you zoom, it does it around the cursor. That is to ...
3
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0answers
73 views

How to calculate subsurface scattering weights for fast skin shading

This question is in reference to the method described in ShaderX7 section 2.4 "Fast Skin Shading" by Hable et. al. The part I do not understand is how they derived the weights for the individual ...
0
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1answer
51 views

Why is the z direction away from the screen/viewer?

I wonder what is the reason that when z increase, the objects appear far away and when z is negative, the object is behind the camera?

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