Design : GLSL compile #118862

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Gangneron · 2024-02-28T18:31:22+01:00

Gangneron commented

2024-02-28 18:31:22 +01:00

The GLSL language was implemented in the text editor in 462c144f41. The objective now is to be able to compile the shaders created so that they can be applied to objects.
For this I have two solutions but I don't know which one to choose.
The first is to create a new file which would contain the code below and allow it to compile. These two parts of code are together in the same file.
#include <cstdio> GLuint LoadShader(GLenum type, const char *filename) { Gluint shader = 0; GLsizei logsize = 0; GLint compile_status = GL_TRUE; char *log = NULL; char *src = NULL;

/* creating a vertex shader */
shader = glCreateShader(type);
if(shader == 0)
{
    std::fprintf(stderr, "unable to create shader\n");
    return 0;
}

/* loading source code */
src = LoadSource(filename);
if(src == NULL)
{
   std::fprintf(std::err, "unable to load file")
    /* theoretically, the LoadSource function has already displayed a message
       error, we will just delete our shader
       and return 0 */
    
    glDeleteShader(shader);
    return 0;
}

/* source code assignment */
glShaderSource(shader, 1, (const GLchar**)&src, NULL);

/* shader compilation */
glCompileShader(shader);

/* free source code memory */
free(src);
src = NULL;

/* check for compilation success */
glGetShaderiv(shader, GL_COMPILE_STATUS, &compile_status);
if(compile_status != GL_TRUE)
{
    /* compilation error recovery of error log */
    
    /* we get the size of the error message */
    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logsize);
    
    /* we allocate a memory space in which OpenGL will write the message */
    log = malloc(logsize + 1);
    if(log == NULL)
    {
        std::fprintf(stderr, "unable to allocate memory!\n");
        return 0;
    }
    /* content initialization */
    memset(log, '\0', logsize + 1);
    
    glGetShaderInfoLog(shader, logsize, &logsize, log);
    std::fprintf(stderr, "unable to compile shader'%s':\n%s",
            filename,log);
    
    /* don't forget to free the memory and our shader */
    free(log);
    glDeleteShader(shader);
    
    return 0;
}

return shader;

}
`

the advantage is that there is normally not much additional development to be done and the code seems simple. The downside is that you will probably need to include OpenGL or other files and this possibly creates a 2nd compilation system in Blender.

The 2nd solution would be to use an already existing system (if it exists) and use it. The advantage is that there is no new implementation to do. The disadvantage is that you have to do longer searches and the results will require more code, take longer to develop and increase the risk of reference problems, bugs, conflicts possibly...
I could try to finish Pr #113938 to have better performance but without guarantees and without rapid results

but before starting development I wanted to collect opinions or advice on the subject

The GLSL language was implemented in the text editor in 462c144f41. The objective now is to be able to compile the shaders created so that they can be applied to objects. For this I have two solutions but I don't know which one to choose. The first is to create a new file which would contain the code below and allow it to compile. These two parts of code are together in the same file. `#include <cstdio> GLuint LoadShader(GLenum type, const char *filename) { Gluint shader = 0; GLsizei logsize = 0; GLint compile_status = GL_TRUE; char *log = NULL; char *src = NULL;` /* creating a vertex shader */ shader = glCreateShader(type); if(shader == 0) { std::fprintf(stderr, "unable to create shader\n"); return 0; } /* loading source code */ src = LoadSource(filename); if(src == NULL) { std::fprintf(std::err, "unable to load file") /* theoretically, the LoadSource function has already displayed a message error, we will just delete our shader and return 0 */ glDeleteShader(shader); return 0; } /* source code assignment */ glShaderSource(shader, 1, (const GLchar**)&src, NULL); /* shader compilation */ glCompileShader(shader); /* free source code memory */ free(src); src = NULL; /* check for compilation success */ glGetShaderiv(shader, GL_COMPILE_STATUS, &compile_status); if(compile_status != GL_TRUE) { /* compilation error recovery of error log */ /* we get the size of the error message */ glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &logsize); /* we allocate a memory space in which OpenGL will write the message */ log = malloc(logsize + 1); if(log == NULL) { std::fprintf(stderr, "unable to allocate memory!\n"); return 0; } /* content initialization */ memset(log, '\0', logsize + 1); glGetShaderInfoLog(shader, logsize, &logsize, log); std::fprintf(stderr, "unable to compile shader'%s':\n%s", filename,log); /* don't forget to free the memory and our shader */ free(log); glDeleteShader(shader); return 0; } return shader; } ` the advantage is that there is normally not much additional development to be done and the code seems simple. The downside is that you will probably need to include OpenGL or other files and this possibly creates a 2nd compilation system in Blender. The 2nd solution would be to use an already existing system (if it exists) and use it. The advantage is that there is no new implementation to do. The disadvantage is that you have to do longer searches and the results will require more code, take longer to develop and increase the risk of reference problems, bugs, conflicts possibly... I could try to finish Pr #113938 to have better performance but without guarantees and without rapid results but before starting development I wanted to collect opinions or advice on the subject

Gangneron added the

Type

Design

label 2024-02-28 18:31:22 +01:00

Iliya Katushenock added this to the Python API project 2024-02-28 18:32:08 +01:00

Iliya Katushenock added the

Module

EEVEE & Viewport

label 2024-02-28 18:32:11 +01:00

Miguel Pozo commented

2024-02-29 19:11:37 +01:00

Python already has a GPU module that allows compiling GLSL shaders.
Unless I'm missing something that already covers what you're describing, and it has the advantage of working on Metal too.

Python already has a [GPU module](https://docs.blender.org/api/current/gpu.html) that allows compiling GLSL shaders. Unless I'm missing something that already covers what you're describing, and it has the advantage of working on Metal too.

Gangneron commented

2024-02-29 19:21:46 +01:00

The goal is not to use python to create a shader but to be able to press the execute button and execute custom GLSL shaders. so you need a system to compile the shaders

Gangneron commented

2024-02-29 19:23:49 +01:00

Plus I would like it to work on all platforms.

Miguel Pozo commented

2024-02-29 20:22:22 +01:00

The goal is not to use python to create a shader but to be able to press the execute button and execute custom GLSL shaders.

Executing shaders in what context? Could you provide a specific example of how a user would use this?

> The goal is not to use python to create a shader but to be able to press the execute button and execute custom GLSL shaders. Executing shaders in what context? Could you provide a specific example of how a user would use this?

Gangneron commented

2024-02-29 21:03:28 +01:00

For example you write the following shader in the blender text editor.

you will want to execute it on an

object in your scene for example. You must therefore compile the shader and execute it and this is where the compilation system comes in. When you press run this compiles the shader and runs it on where the objects.

For example you write the following shader in the blender text editor. you will want to execute it on an object in your scene for example. You must therefore compile the shader and execute it and this is where the compilation system comes in. When you press run this compiles the shader and runs it on where the objects.

Capture d’écran 2024-02-25 à 20.28.54.png

226 KiB

Miguel Pozo commented

2024-03-04 17:58:41 +01:00

I think for something like what you describe, compiling a shader is the least of your problems, and something that is already supported anyway.
Your example seems to be missing many details, and still doesn't clarify what the actual goal is (why is this better than a draw_handler?). And your GLSL code doesn't make sense (you're mixing a compute and a vertex shader on the same file ?)

I would suggest you to explore your ideas by building an addon first.

I think for something like what you describe, compiling a shader is the least of your problems, and something that is already supported anyway. Your example seems to be missing many details, and still doesn't clarify what the actual goal is (why is this better than a `draw_handler`?). And your GLSL code doesn't make sense (you're mixing a compute and a vertex shader on the same file ?) I would suggest you to explore your ideas by building an addon first.

Gangneron commented

2024-03-04 18:18:07 +01:00

the code of shader have create by Clément Foucault in #116793 and i don't check if was good.

Gangneron commented

2024-03-04 18:22:03 +01:00

@pragma37 For me GLSL no compile when write the script and no execute

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Design : GLSL compile #118862