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I want to debug a GLSL Shader.
What i need is to send Strings information.
I have tried FBO but this is not a clean way
Is there a way to send log to the main program?
You can do following if you want to have some kind of your own error codes.
You can use transform feedback.
Transform feedback cant store strings . It is generally used to store per vertex or per primitive attribute.You may define some error codes. for example
In Application
#define VERTICES_TRANSFORMED_WRONGLY 1
in VS shader
#define VERTICES_TRANSFORMED_WRONGLY 1
void main(void)
{
if(condition for error met)
write error code(VERTICES_TRANSFORMED_WRONGLY) to Transform feedback.
}
In Application
Read this transform feedback if it has any error code you know what went wrong.
You can attach transform feedback after every shader stage.
[Edit suggested by BDL] :
You cant attach Transform Feedback after fragment shader but you can do something similar with FBO for fragments shader stage.
Note : I would still suggest you to use tools you have already been referred like Renderdoc ,glDebugger,Nsight .
No, there is no way to send strings from a shader to a main program.
What you usually do is to output specific colors for specific cases. Depending on your hardware CodeXL or Nvidia NSight might also help.
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I have terrain separated by chunks and I would like to put environment (For example, rocks, trees, etc..) in each chunk randomly.
My question is related to how to implement such system in OpenGL.
What I have tried:
Solution: Draw the environment with instancing once for all the terrain (not a specific chunk)
Problem: I except the chunk to sometimes take a bit to load and because I am using threads the environment will appear as floating.
Solution: Draw the environment with instancing for each chunk.
Problem: To draw each chunk, I will need to bind the VBO for the chunk, draw the chunk, bind the VBO for the environment (and the VAO probably) and draw it.
I don't want to put so many glBindBuffer functions because I heard it is slow (Please correct me if I am wrong)
(Not tried) Solution: Somehow merge the vertices of the terrain with its environment and draw them together.
Problem: My terrain is drawn with GL_TRIANGLE_STRIP so this is a first problem, the second problem(?) is that I don't know how well it will function (talking speed).
I tried looking up solutions on the internet but didn't seem to find any that relate to chunks.
Anyone know how other games that uses chunks do that? Is there a way to do it without causing a lot of speed decrease?
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I have a quite specific question: I want to draw a matrix of numbers in a greyscale image. The higher the number the brighter the output. Is there a way to do that in a C++ programme without having dependencies to a graphic library like Qt?
I looked through some examples of ImageMagick, but I'm not sure how to implement its functions in C++.
Answer
In case someone stumbles upon this question:
a modified code of the example shown here was a handy and easy solution
It's hard without a library. SFML seems easy to use.
EDIT
Also you have 3 other questions hidden in your question:
1- To save an image you can use sf::image::saveToFile
2- To get brighter number for higher number: You need to normalize your numbers to [MinColorYouWant MaxColorYouWant] (for example: [128,255]). Thus the normalization value corresponding to each number will become the color of the number.
3- SFML uses RGBA images by default. Just set the RGB channels equal to make it look greyscale.
EDIT 2 : I've fixed the example normalization from [128,256] to [128,255].
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I need to convert text (string+font) into mesh (vertices, indices, triangles etc), but I don't need to draw anything. I'll just get a string from one API and push it as vertices & indices to another. What's the simplest/easiest/best way of doing this? Font metrics and text placing are of course available and no other transforms are needed.
I'm currently working with VC++. However, any kind of OpenSource (C/C++, C#, VB,...) and "non-open but free" COM/.NET -libraries would be great.
I've heard of FreeType. Does it answer my prayers or is there something even better?
EDIT: As Nico Schertler commented, there seems to be Mesh.TextFromFont -function in DirectX -libs that probably does the trick. Thank you Nico! I'll update when I have time to test this in practise.
Mesh.TextFromFont sounded good but it didn't save the day since I couldn't figure out how to get the actual point/triangle data from the mesh -object.
But then I found this. In this project, GraphicsPath is used to create a point-path from a glyph. Then the points are coverted into Polygons and the polygons are then tesselated into triangles using Poly2Tri.
A quick browse through the source code and with some small modifications and code stripping I ended up with a nice .NET -dll with one simple static function that does everything I need.
To convert a text into a mesh you can use the ttf2mesh library. This library consists of just one C-file and allows to open truetype font (.ttf) and convert it glyphs to a mesh objects in 2d or 3d space. There is an examples in the repository.
An interesting feature is the lack of dependency on any third party library (like libfreetype). Also in the examples there is a ttf2obj program that allows you to convert a font file to an OBJ file.
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I have a problem while running my game. The model that I import in the game is quite big, making the fps drop down. That's okay but when I get the camera off from the model, it still stays slow. As other games do, when looking at a high resolution model, the game slows down but when not looking at it, it gets faster. However my game stays slow all the time. Can anyone help me?
You need to implement clipping, so that you don't render the object (i.e. pass it through the graphics pipeline) when it's not visible.
There are many techniques and algorithms/data structures for this, ranging from manual view frustum-testing, to more advanced spatial-querying data structures (BSPs, quadtrees, octrees and so on).
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I want to begin looking at Direct X, but don't just want to try and throw myself into it. What are some good resources to get ones feet wet?
I highly recommend Toymaker's tutorials. Helped me greatly when I was first starting out with DX and was just as good as a reference later on.
The other thing to do would to set up some small projects that use DX that increase in difficulty as you go. If you'd like a starter list (from easy to hard):
Compiling using DX libraries (I always remeber having trouble linking the libraries correctly in Visual Studio).
Change background colour.
See a model on-screen.
Moving the model with input.
A camera.
Apply a texture to your model.
Add multiple models to your scene.
Add lighting.
Create your a simple rectangle model and display a texture on it.
Get comfortable with all that and then have a look at shaders, advanced lighting and animation.
There are quite a few books on directX, but there is so much freely available information on the web these days, I would just jump right in there.
A good place to start is just to do a youtube search for DirectX Tutorials. In my opinion, this is a fun and interesting way to get started learning a new dev skill.