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Questions tagged [rendering]

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3
votes
1answer
503 views

What is the equation for flat shading?

Is there an equation for flat shading? To my understanding, it is this: $$I = I_a \times K_a + F_{att} \times I_l \times (K_d \times (N \times L))$$ Final intensity = ambient reflection x ...
8
votes
2answers
401 views

How to handle a parametric equation in raytracing?

After taking a look at the Mobius strip, I noticed its equation is really simple and tried to add it into my Raytracer. I tried a "naive" way by simply generating N...
1
vote
2answers
657 views

How to calculate the RGB intensity values at center of face using flat shading?

Consider a triangular face of three vertices A(0,2,1), B(3,0,1) and the origin, and the normal vectors at the vertices are nA=(0,0,1), nB=(1,1,0) and nO=(-1,-1,1), respectively. The incident light is ...
4
votes
1answer
279 views

How do you calculate cos(theta) for diffuse in flat shading?

Consider a triangular face of three vertices $A=(0,2,1)$, $B=(3,0,1)$ and the origin $O$, with normal vectors $(0,0,1)$, $(1,1,0)$, and $(-1,-1,1)$, respectively. The incident light is white and ...
1
vote
1answer
264 views

Beginner CG Research Project [closed]

This summer I will be working with a professor on a research topic of my choice, in the field of graphics & simulation. While my professor is knowledgeable in the area he is being very hands off ...
1
vote
1answer
80 views

Need help with VBO/VAO

It's been a long time since I last used OpenGL and I can't figure out VAOs anymore... I want to make a simple voxel engine using geometry shaders. This is what I want to do: vbo1: array of GLfloat ...
5
votes
1answer
458 views

Energy conservation of BRDF

I'm reading Advanced Global Illumination. Here is the part confusing me: What do the second equation and $\delta$-function mean? Why the third equation is a sufficient condition even though a reason ...
4
votes
1answer
344 views

Why the BRDF of specular reflection is infinite in the reflection direction?

I know the BRDF of specular reflection is nonzero only in the reflection direction. But why it is infinite? A paragraph on page 36 of Advanced Global Illumination:
1
vote
2answers
696 views

Can you batch vertex data and still sort by depth?

In order to reduce the amount of draw calls per frame I've decided to use a vertex array object to store vertex data from several different meshes. More precisely, I use the vao to the define the ...
5
votes
2answers
491 views

My perspective projection is messed up?

So I've been messing with perspective projection matrices recently. I used numpy and GTK/Cairo to make a very small Python renderer. I'm very confused with the results I'm getting though. I took this ...
1
vote
1answer
408 views

How can I send custom bitmap to frame buffer?

I was trying to make a CPU-based ray tracer but I know after all the calculation I will end up with an array of pixels. I don't know how to paint it on the screen. What are the various ways to do that?...
8
votes
2answers
542 views

What is a good approach for handling uniforms in modern OpenGL?

I'm creating a renderer using modern OpenGL (3.1 and up) and now I'm trying to create an efficient but flexible way of handling uniforms. I've been reading up on uniform buffer objects and on what a '...
1
vote
1answer
634 views

Which technique is fast to generate real-time reflections?

I want to know about some technique with which i can generate nice reflections on the surface. I know one conventional technique where we invert an object and render it and blend it with the floor but ...
3
votes
1answer
1k views

Multiple VAO share a VBO

Let's say I have a have 10 different terrains. Each terrain have the same x and z coordinates, but they have different y coordinate, normals and colors. The indices used for element rendering is also ...
3
votes
0answers
344 views

Calculating intensities of Virtual Point Lights in Instant Radiosity from IES lights

Short introduction I created a function that interpolates the IES luminious intensities (candelas) using Hermite interpolation, so in my code all light sources have $I(\theta, \phi)$ function - but ...
6
votes
1answer
105 views

Trying to understand environmental cubemaps

I am trying to implement a physically based renderer, in OpenGL. I was planning to implement the Cook-Torrance BRDF. I read about radiance cubemaps (for reflections), like the one discussed here, for ...
1
vote
2answers
364 views

Challenges of Offline Rendering

What are some of the challenges of Offline Rendering? I know one problem that is faced is performance and rendering times, are there any more issues? Path Traced photos seem to have reached the ...
5
votes
1answer
115 views

Volumetric Obscurance : line integrals

I would like to compute volumetric obscurance with line integrals like described in this paper. For a 2D sample, it is possible to know the "depth in sphere". But I don't understand how they compute ...
6
votes
1answer
175 views

Mix shader looks wrong on my path tracer

I apologize if my methods seem way off because this is my first time trying to build a path tracer and I'm struggling quite a bit. Currently, I am trying to mimic the "mix shader" node in Blender 3D ...
4
votes
1answer
536 views

Do animation studios like Pixar, Dreamworks, and Disney use super-sampling?

Does any of their rendering techniques involve rendering an area at a higher resolution just to scale it down in order to mitigate artifacts? I know they use ray methods rather than rasterization ...
6
votes
2answers
4k views

How to achieve gimbal lock with Euler angles?

I was studying about Euler angles and I came across the problem gimbal lock which can occur by using Euler angles. In gimbal lock we lose one axis of rotation. But how? And when does it happen? On ...
6
votes
1answer
475 views

Do GPU performance improve when rendering at native or half resolution, compared to fixed scaling?

This might be an odd question, but I was wondering if you could improve GPU performance with games, comparatively, when using doubles/halves of the native resolution, instead of an odd ratio of that. ...
6
votes
1answer
293 views

Binary scene voxelization using imageStore - problem

This problem has been haunting me for some time but I was busy with other things. I can't finish my GI technique (specifically occlusion step) without solving it. I made a binary scene voxelization ...
6
votes
0answers
433 views

Percentage-closer Soft Shadows implementation

I am trying to implement the Percentage-closer Soft Shadows (PCSS) from NVidia inside Unity but I am facing some issue and I don't know where they come from and then, I do not know how to solve them......
12
votes
1answer
301 views

Ocean Wave Rendering

How could I generate the waves for a water body with whitecaps & foam and variable intensity of the waves? Is the surface a mesh with a normal map? Is there a formula for generating that? Is there ...
7
votes
1answer
2k views

Depth of Field in Path Tracing: What do I do with the secondary ray?

How can I implement Depth of Field in my Path Tracer? I have read this article which explains the theory behind everything & I already have a good understanding of what this effect needs to ...
8
votes
1answer
1k views

Area Lights in Path Tracing

I have been following the scratchapixel ray tracing tutorials online which have been great at explaining the theory behind everything & how to implement it. However, I reached the point where I ...
5
votes
0answers
112 views

How is glint rendering done in Ray Tracing?

How is glint rendering done with ray tracing in the photo below? Is it just a simple normal map? I found a paper online that describes the exact same method used in the photo above but I have no ...
6
votes
1answer
1k views

What are the benefits of downscaling on modern games?

I'm a software engineer and although I currently don't work on anything related to computer graphics, I understand how downscaling works, what I don't understand is why most modern games default to ...
6
votes
1answer
576 views

How is data stored into a frame buffer?

I am an electronic engineer. I am trying to design (personal project) a 3D graphics hardware renderer. It shall only render wireframes at this stage, no filling and no shading, not even backface ...
4
votes
2answers
182 views

Can I have lower color bit depth in sample buffer than target framebuffer?

I´m looking into uses of high amount of samples in multisampling. If I have an RGBA8 framebuffer and render to it using multisample with many samples, say 32, dithering on per-sample level should ...
1
vote
3answers
292 views

How are Physically Based Rendering Methods Researched?

Recently a question that came to my mind was that How are Physically Based Rendering Techniques researched and developed? Do people just use current equations by physicists or do they create their own?...
8
votes
2answers
646 views

Eye Parallax Refraction

I am trying to implement the Parallax Refraction effect explained by Jorge Jimenez on this presentation: http://www.iryoku.com/downloads/Next-Generation-Character-Rendering-v6.pptx and I am facing ...
5
votes
2answers
117 views

Correctness of logical steps for create the matrix of viewing transformation

In general, I understand the creation of viewing transformation matrix, but I have my doubts. For example, let's say that a world coordinate (called $A$) has a center at $(1,1,1)$, and the view ...
5
votes
2answers
383 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 ...
9
votes
1answer
168 views

searching for acceptable quality shadow mapping techniques

Recently while searching of solving the shadow acne problem of traditional shadow mapping I implemented exponential shadow maps. It did the trick (no acne at all) but at the same time introduced other ...
8
votes
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 ...
2
votes
1answer
452 views

How to clip multiple tiled textures to polygon in Webgl / opengl

I have a bunch of planes each with their own texture in a grid. Currently I am rendering these as separate planes, each with their own texture, although I could use a single plane with multiple faces. ...
1
vote
2answers
383 views

Only show opaque objects behind transparent objects

I would like to make certain objects in my scene transparent, but only the parts visible to the camera when opaque. Currently, when I make objects transparent, I can see other transparent objects ...
1
vote
1answer
49 views

Photo-realism blind experiment [closed]

I need a lot of real time rendered images and real images where it's recorded which one is which to prove either way whether existing gaming computers have the hardware to be photo-realistic to ...
11
votes
3answers
2k views

Correct Specular Term of the Cook-Torrance / Torrance-Sparrow Model

For a while I have been doing some research on the topic of Physically Based Rendering. One reflection model that is mentioned over and over is the Cook-Torrance / Torrance-Sparrow model. It seems ...
5
votes
1answer
325 views

How do CAD programs render non-polygonal 3D objects?

How CAD programs handle displaying B-Reps and NURBS/T-Splines in their viewports? Assuming viewport uses OpenGL API - are those programs transform every object into triangles and creating/deleting ...
3
votes
1answer
338 views

ping pong between same framebuffer two color attachments

In order to optimize I'm trying to set up a setup which ping pong between same framebuffer two color attachments to apply some postprocess effects. It seems to work (effects are applied) but ...
1
vote
0answers
96 views

Can I Implement Clustered Lighting with WebGL?

Do current WebGL capabilities allow to use Clustered Lighting? If not what is it missing to allow that? Basically WebGL uses GLES 2, so is that possible with GLES 2? I want to implement this one: ...
2
votes
2answers
142 views

Can I use the same vertices to render multiple things?

I'm passing my vertex shader a bunch of vertices and color data. I would like to first render the triangles and then render a point at each vertex. The triangles render fine, but I can't think of a ...
1
vote
1answer
788 views

Dark stripes on surfaces in V-Ray when rendering to texture (baking)

I am working in 3DS Max with V-Ray 3.4. I have recently been encountering strange artifacts on baked textures. Surfaces that should be flat smooth objects render with dark stripes or other unusual ...
8
votes
2answers
159 views

Are vertices reprocessed per-poly for indexed meshes?

I've been digging a bit into what actually happens at a hardware level on the GPU, and found NVidia's Life of a triangle which explains the pipeline pretty well, at least for green boxes. One thing I ...
4
votes
1answer
305 views

How to create specular surface in Mitsuba Renderer

I am a newbie in computer graphics and I am trying to develop a special case of path tracing really slowly! But first: I came up studying the Mitsuba renderer and one of its uses in the so-called GDPT ...
4
votes
1answer
645 views

What is the definition of “motion to photon” in VR?

The rough definition of "MTP" is clear. But the exact one is not. You can refer to these links: What is Motion-To-Photon Latency? | chioka.in Motion-to-photon latency | xinreality.com/wiki. But from ...
5
votes
1answer
165 views

Efficiently rendering sprites

In order to naïvely render sprites, you can send single rectangles with their position, rotation, size, and texture. This is very easy, but given that reducing state changes, draw calls, and data ...