Questions tagged [c++]

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2answers
394 views

How to use multithreading in 3D software renderer to speed up fetching texture values

The biggest bottleneck of my code is fetching texture RGB values from memory. My code looks something like this: ...
1
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0answers
115 views

Finding Segments in Continuous line

I'm trying to break a continuous line segment into multiple, straight segments. I've tried using the Hough transform but have found it unreliable for getting the line segments I'm looking for and ...
5
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0answers
190 views

Computation of conservative AABB for clipped triangle

I'm currently trying to implement a fast algorithm for KD-Tree construction using SAH, as described in this paper: On building fast KD-trees for ray tracing, and on doing that in O(N log N) I found ...
2
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0answers
122 views

Image Laplacian incomprehension

I am reading and trying to implement a research paper. It uses openGL to define which part of an image to use in order to reconstitute a big image composited of several images. In order to do so, I ...
2
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1answer
385 views

Jos Stam's “Stable Fluids” boundary conditions

In the paper Stable Fluids by Jos Stam, I am confused about the boundaries in the set_bnd function in the code. I don't know what kind of boundaries is this. Is it Neumann boundary condition or ...
1
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1answer
737 views

How can I utilize all cores of CPU In my ray tracer with std::thread?

I have been working on a ray tracer and I was trying to use multiple threads to maximize the performance. I tried couple of approaches but there's no difference in performance. Here's my shot... <...
3
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0answers
411 views

Problem with specular BRDF (Monte Carlo & Path Tracing)

Above on the left is my attempt and on the right is what I'm aiming for.As you can see my sphere with the specular brdf has a weird dark ring In my radiance function I am recursing through the ...
4
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2answers
190 views

Strange behaviour in vertex shader with divisions

This is the vertex shader code: ...
2
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2answers
489 views

Can somebody explain this Ray Tracing Function?

I am currently reading through Peter Shirley's Ray Tracing in One Weekend. In the beginning chapters where the author introduces diffuse surfaces we a presented with this function: ...
1
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1answer
841 views

Skia example code not writing an image

I am just trying to make a simple Skia program. A very simple program, but as I run this code, the output image file never writes anything. I am running this code on VS 2015 and included the skia.lib ...
4
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1answer
118 views

NormalMap problems: bumps work, but shade does not

I've been trying to figure this out for a few days now, but I just can't get it right. I've read multiple tutorials and possible explanations, I even watched a java tutorial without finding the ...
1
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1answer
242 views

How to organize Lights and Models?

I'm interested in how to organize in code (I prefer C++) lighting. Problem is: I have Scene which contains Model where model ...
1
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1answer
185 views

My (ADS) shader doesn't render the light direction correctly

This is what I'm doing: vertex shader: ...
1
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1answer
336 views

Am I passing the correct matrices for my shader? openGL/C++

On page 89 of David Wolff - OpenGL 4.0 Shading Language Cookbook book, it suggests a way to set up up a Phong shader in the fragment stage. It lists some different matrices to pass via uniform, and I ...
1
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1answer
291 views

Swap buffers twice does not show the first scene

If you clear the color buffer and draw a triangle, you have nothing in the buffer that is shown in the screen and a triangle in the other buffer, so you have to swap buffers for showing the triangle. ...
7
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2answers
561 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...
6
votes
1answer
2k views

How can I generate mipmaps manually?

This question has an answer here: https://stackoverflow.com/questions/42596516/generating-mipmaps-manually It was a silly mistake. Sorry for the inconvenience. OpenGL is fairly difficult to learn. ...
5
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1answer
283 views

Artifacts when gamma correcting

Doing post-process gamma correction is showing texture artifacts, here is a small example on a skybox: The first image is gamma correcting on the skybox shader and seems correct, the lower is doing ...
1
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2answers
1k 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 ...
1
vote
1answer
104 views

Does programs like After effects and Unity engine use graphics library to render custom guis?

I was always interested how programs like: Unity, AE, godot engine and other render their custom guis. So my question is, do they use graphics library to render custom guis or something else. If they ...
1
vote
1answer
642 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?...
1
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1answer
732 views

Point respect to plane

How do I classify a point with respect to a plane, returning whether the point is inside, outside, or coplanar? I know that if a point is on the plane the Dot product + the plane distance would equal ...
2
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2answers
3k views

Can one VAO store multiple calls to glVertexAttribPointer?

If no, Should I create a new VAO for every VBO that has its own vertex attribute configurations? Could you please give me a snippet code example that shows how to use one VAO for multiple VBOs? All ...
8
votes
2answers
767 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 '...
3
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2answers
820 views

How to watch image being ray traced?

In my ray tracer, I render my images out to a .PPM file and then view it in photoshop. To make things easier and faster I want my ray tracer to open up another window and show the image being rendered ...
4
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1answer
1k views

How to get the GLFW_CONTEXT_VERSION_MAJOR value?

This code snippet: ...
12
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1answer
2k views

What does “makeContextCurrent” do exactly?

I am pretty confused about that function. GLFW Context reference says as follow: This function makes the OpenGL or OpenGL ES context of the specified window current on the calling thread. A ...
3
votes
3answers
244 views

Is there a difference between window and screen in computer graphics?

I've been reading some code which setups a ray tracer and I've realized I've a doubt regarding what's a screen and what's a window in this context. Here's the relevant code using Qt: ...
5
votes
1answer
2k views

Modern way of light sources in OpenGL?

In older versions of OpenGL there were things like: glLight(...) gl_LightSourceParameters The modern way of doing lighting is passing light source parameters manually to the shader in vao-s? Or ...
5
votes
1answer
187 views

How to rasterize a line when the background color is not always white?

I've to rasterize a line taking into account not only the background color of the screen, which is white, but also the color of other objects in the scene. In my case, I've just another object, a ...
1
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3answers
362 views

How are the colors for each pixel from a Ray Tracer stored in an Image?

I have begun learning how to create a Ray Tracer and 1 thing I am confused about is how the pixel color from a Ray Tracer is stored into an image. Do we use SetPixel...
4
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1answer
239 views

Material Layering

So after reading this Unreal Engine 4 Documentation page: https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/LayeredMaterials/ (Which describes how to use material layering in UE4) ...
4
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1answer
345 views

Flexible Vertex Format Constants in Direct3D 11

How do you migrate Flexible Vertex Format Constants (or FVF codes) from DirectX 9 to Direct3D 11? Old code: ...
5
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2answers
121 views

Problem with Basic Diffuse Lighting

So recently I have been learning how to implement Diffuse Lighting in DirectX and I have done so with the following code: ...
3
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1answer
324 views

Creating a gently moving 2D fog effect

I am trying to create a fog-like effect, similar to that found using perlin noise. I know where I can find information about that effect, but it's harder for me to tell if it's an efficient route for ...
1
vote
1answer
455 views

How to use Shaders with vertex & index buffers?

I'm trying to render a randomly generated terrain with vertex buffers and OpenGL. I want to use a shader to color the terrain, but it seemms like my shader isn't used. I have used shaders before when ...
7
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1answer
328 views

Ray casting in fan configuration produces point cloud with curvature, how to eliminate curvature?

I'm attempting to perform an intersection test using ray casting (not sure if correct term so please forgive me if not) and am outputting the intersections as a point cloud, and the point cloud shows ...
3
votes
1answer
954 views

Compute shader not updating buffer, or vertex buffer unable to read the updates

I'm learning OpenGL compute shaders and following this guy's code, and I have stuff drawing, but not updating. The particles are spread out in their starting positions, but they stay there. ...
7
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1answer
165 views

Proper architecture for rendering history of streamed data (points)

Overview My program receives some data points (0-400 per sec). ...
4
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1answer
250 views

Can't make blending work

I have a 3 dimensional dataset where each value of the dataset is normalized to [0, 1]. I want to visualize this dataset by using texture, and blending. However, it ...
4
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1answer
118 views

Uniform not set, despite valid location

I try to write a simple triangle mesh renderer with OpenGL. ...
5
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2answers
496 views

How to check which API's are available on a given machine?

I'm building an engine, which has Vulkan for its primary rendering engine. But to have at least some backwards compatibility with devices that don't have drivers for it (mainly mobile) I want to ...
6
votes
1answer
466 views

Perspective correct interpolation of normal values

I'm currently writing a software rasterizer and I'm at the point where I can draw arbitrary triangles with vertex colors and perspective correct texture mapping. I do point and directional lighting by ...
6
votes
1answer
521 views

Open GL Shader Storage Buffer Objects to replace Vertex Attributes

At first: I already posted this on the stackoverflow community. I'm new and didn't know about this community here. I apologize. I basically got the same question as the guy who asked here: https://...
7
votes
1answer
846 views

Resulting Probabilty Density in Path Tracer for paths using Next Event Estimation

I am trying to implement my own Gradient Domain Path Tracer by following the code of this guy who already implemented it: https://gist.github.com/BachiLi/4f5c6e5a4fef5773dab1 I already managed to ...
5
votes
1answer
956 views

Role of PDF of Uniform Random Sampling in a path tracer

I am trying to implement my own path tracer but before arriving to the question I want to give you a short overview: In the implementation of the rendering equation I use some particular technique in ...
3
votes
1answer
296 views

Generate this kind of 2d burst or pulse algorithm?

I'm currently trying to develop a game using Cocos2d-x using C++. I really need to generate this burst or (donut-shaped) pulse. I'm having a difficult time how to generate such shape. At first, I was ...
3
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0answers
843 views

Represent vector with arrow

Another code review question. I am trying to draw an arrow to represent a vector. I have started with an unit arrow with vertices defined as follows: ...
3
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1answer
485 views

Ray-tracing the Cornell Box results in really inconsistent image

So I have a vector of glm::vec3 containing the triangles for the classic Cornell Box called triangles. The Draw method casts a ray for each pixel on the screen and ...
4
votes
1answer
660 views

How to compensate low amount of rays reaching the light in a Path Tracer

I am trying to implement for research purposes a path tracer, but so far but results are not so good and I will explain you why. The general idea before getting to the code: I am working on paths ...