[DEV BUG] NPOT capability check fails on GLES despite support for GL_OES_texture_npot extension

[kholbrook1303]

Please confirm the following points:

• This report is NOT about the Android apps in the Play Store
• I have searched the project page to check if the issue was already reported

Affected Project

libprojectM (including the playlist library)

Affected Version

4.1.4

Operating Systems and Architectures

Linux (x86_64)

Build Tools

Build Tool: CMake

Additional Project, OS and Toolset Details

Working with VS 2022;
Using on Windows 11 and also in Raspberry Pi OS Bookworm

Type of Defect

Graphical issue (rendering glitches, no or broken rendering result)

Log Output

Logging I added to SOIL2 to determine what was occuring:
[2025-10-01 06:58:27] Checking NPOT texture capability...
[2025-10-01 06:58:27] Checking for GL extension: 'GL_ARB_texture_non_power_of_two'
[2025-10-01 06:58:27] Using modern glGetStringi method for GL >= 3.0
[2025-10-01 06:58:27] SOIL_GL_GetProcAddress: Trying to load function 'glGetStringi'
[2025-10-01 06:58:27] OpenGL ES platform with SOIL_NO_EGL defined: function pointer NULL for 'glGetStringi'
[2025-10-01 06:58:27] Failed to get glGetStringi function pointer.
[2025-10-01 06:58:27] Checking for GL extension: 'GL_OES_texture_npot'
[2025-10-01 06:58:27] Using modern glGetStringi method for GL >= 3.0
[2025-10-01 06:58:27] SOIL_GL_GetProcAddress: Trying to load function 'glGetStringi'
[2025-10-01 06:58:27] OpenGL ES platform with SOIL_NO_EGL defined: function pointer NULL for 'glGetStringi'
[2025-10-01 06:58:27] Failed to get glGetStringi function pointer.
[2025-10-01 06:58:27] GL_ARB_texture_non_power_of_two: NOT SUPPORTED
[2025-10-01 06:58:27] GL_OES_texture_npot: NOT SUPPORTED
[2025-10-01 06:58:27] NPOT capability: NOT PRESENT

Describe the Issue

While testing the sprite feature on Raspberry Pi 5 on Desktop OS Bookworm, I noticed that the textures were being resized. This did not occur on Windows.

The system is running:

• OpenGL core profile version string: 3.1 Mesa 24.2.8-1~bpo12+rpt4
• OpenGL ES profile version string: OpenGL ES 3.1 Mesa 24.2.8-1~bpo12+rpt4

The system does support NPOT textures: GL_OES_texture_npot

When using cmake with -DENABLE_GLES=ON the issue occurred, without did not, indicating this was due to GLES.
Upon checking, I noticed that in SOIL2.c there is a NPOT compatibility check which does indeed check for "GL_OES_texture_npot", however, there is an issue in SOIL_GL_ExtensionSupported.

In this case SOIL_X11_PLATFORM is defined and is running 3.1, but when trying to load 'glGetStringi' no address is returned because SOIL_GLES2 and SOIL_NO_EGL are both defined.

I have a fix for this by essentially failing over to the glGetString method (instead of returning unsupported) which does identify GL_OES_texture_npot properly therefore does not resize a NPOT texture.

If this is ok then I can post a PR, however please let me know if you would rather fix this in the SOIL_GL_GetProcAddress function.

[kblaschke]

The SOIL2 library in projectM hasn't been updated for like a decade or so. It's possibly a good idea to use the latest available version from SpartanJ/SOIL2 and see if the issue persist. If it does, and it's a bug in the SOIL code, the issue should be reported upstream as well while we can temporarily patch it.

If you can do this, this would be great! Otherwise, I'll see if I can make some room to check this in the coming weeks.

[kholbrook1303]

@kblaschke I went ahead on a test system and migrated to SOIL 1.31 (latest release) and confirmed that they have resolved the issue on their end. They have essentially added a condition in method isAtLeastGL3 to check if verstr is 'ES' and if so, isAtLeastGL3 returns False, allowing it to fail over to legacy glGetString.

The only changes required that I see when migrating to the latest version is SOIL_load_OGL_texture_from_memory no longer supports width and height as a parameter.

What I have done in my tests is use SOIL_load_image_from_memory to obtain the width, height, and channels:

    int width = 0;
    int height = 0;
    int channels = 0;

    unsigned char* image = SOIL_load_image_from_memory(
        M_data,
        M_bytes,
        &width,
        &height,
        &channels,
        SOIL_LOAD_AUTO);

Then proceed with SOIL_load_OGL_texture_from_memory without height and width:.

    unsigned int tex = SOIL_load_OGL_texture_from_memory(
        M_data,
        M_bytes,
        SOIL_LOAD_AUTO,
        SOIL_CREATE_NEW_ID,
        SOIL_FLAG_POWER_OF_TWO | SOIL_FLAG_MULTIPLY_ALPHA);

    m_textures["idlem"] = std::make_shared<Texture>("idlem", tex, GL_TEXTURE_2D, width, height, false);;

TextureManager::Preload and TextureManager::LoadTexture both needed to be updated.

[kblaschke]

The only changes required that I see when migrating to the latest version is SOIL_load_OGL_texture_from_memory no longer supports width and height as a parameter.

That's fine, the size was already determined internally from the image, so these arguments were kinda useless anyway.

I've fully upgraded the SOIL2 dir to v1.31 in addition to your changes and opened PR #911.