GLSL shader compatibility issue when targeting WebGL with wasm32-emscripten

[nii236]

Description

When building the any example with the wasm32-emscripten target, the fragment shader compilation fails with multiple errors indicating GLSL version incompatibility.

Steps to Reproduce

zig build texture_outline -Dtarget=wasm32-emscripten --sysroot /Users/nii236/gamedev/emsdk/upstream/emscripten

Environment

• Platform: macOS
• Zig version: 0.14.0
• Raylib version: 5.6-dev
• Target: wasm32-emscripten
• Browser rendering: WebGL 1.0 (OpenGL ES 2.0)

Logs

➜  raylib-zig git:(devel) zig build texture_outline -Dtarget=wasm32-emscripten --sysroot /Users/nii236/gamedev/emsdk/upstream/emscripten
Now listening at http://0.0.0.0:6931/
INFO: Initializing raylib 5.6-dev
INFO: Platform backend: WEB (HTML5)
INFO: Supported raylib modules:
INFO:     > rcore:..... loaded (mandatory)
INFO:     > rlgl:...... loaded (mandatory)
INFO:     > rshapes:... loaded (optional)
INFO:     > rtextures:. loaded (optional)
INFO:     > rtext:..... loaded (optional)
INFO:     > rmodels:... loaded (optional)
INFO:     > raudio:.... loaded (optional)
INFO: DISPLAY: Device initialized successfully
INFO:     > Display size: 800 x 450
INFO:     > Screen size:  800 x 450
INFO:     > Render size:  800 x 450
INFO:     > Viewport offsets: 0, 0
INFO: GL: Supported extensions count: 71
INFO: GL: OpenGL device information:
INFO:     > Vendor:   WebKit
INFO:     > Renderer: WebKit WebGL
INFO:     > Version:  OpenGL ES 2.0 (WebGL 1.0)
INFO:     > GLSL:     OpenGL ES GLSL ES 1.00 (WebGL GLSL ES 1.0 (1.0))
INFO: GL: VAO extension detected, VAO functions loaded successfully
WARNING: GL: NPOT textures extension not found, limited NPOT support (no-mipmaps, no-repeat)
INFO: GL: DXT compressed textures supported
INFO: GL: ETC1 compressed textures supported
INFO: PLATFORM: WEB: Initialized successfully
INFO: TEXTURE: [ID 2] Texture loaded successfully (1x1 | R8G8B8A8 | 1 mipmaps)
INFO: TEXTURE: [ID 2] Default texture loaded successfully
INFO: SHADER: [ID 3] Vertex shader compiled successfully
INFO: SHADER: [ID 4] Fragment shader compiled successfully
INFO: SHADER: [ID 5] Program shader loaded successfully
INFO: SHADER: [ID 5] Default shader loaded successfully
INFO: RLGL: Render batch vertex buffers loaded successfully in RAM (CPU)
INFO: RLGL: Render batch vertex buffers loaded successfully in VRAM (GPU)
INFO: RLGL: Default OpenGL state initialized successfully
INFO: TEXTURE: [ID 12] Texture loaded successfully (128x128 | GRAY_ALPHA | 1 mipmaps)
INFO: FONT: Default font loaded successfully (224 glyphs)
INFO: SYSTEM: Working Directory: /
INFO: FILEIO: [resources/textures/fudesumi.png] File loaded successfully
INFO: IMAGE: Data loaded successfully (384x512 | R8G8B8A8 | 1 mipmaps)
INFO: TEXTURE: [ID 13] Texture loaded successfully (384x512 | R8G8B8A8 | 1 mipmaps)
INFO: FILEIO: [resources/shaders/glsl330/outline.fs] Text file loaded successfully
WARNING: SHADER: [ID 14] Failed to compile fragment shader code
WARNING: SHADER: [ID 14] Compile error: ERROR: 0:1: '
' : invalid version directive
ERROR: 0:4: 'in' : storage qualifier supported in GLSL ES 3.00 and above only
ERROR: 0:4: '' : No precision specified for (float)
ERROR: 0:5: 'in' : storage qualifier supported in GLSL ES 3.00 and above only
ERROR: 0:5: '' : No precision specified for (float)
ERROR: 0:9: '' : No precision specified for (float)
ERROR: 0:11: '' : No precision specified for (float)
ERROR: 0:12: '' : No precision specified for (float)
ERROR: 0:13: '' : No precision specified for (float)
ERROR: 0:16: 'out' : storage qualifier supported in GLSL ES 3.00 and above only
ERROR: 0:16: '' : No precision specified for (float)
ERROR: 0:20: '' : No precision specified for (float)
ERROR: 0:20: 'texture' : no matching overloaded function found
ERROR: 0:20: '=' : dimension mismatch
ERROR: 0:20: '=' : cannot convert from 'const mediump float' to '4-component vector of float'
ERROR: 0:21: '' : No precision specified for (float)
ERROR: 0:26: '' : No precision specified for (float)
ERROR: 0:27: 'texture' : no matching overloaded function found
ERROR: 0:27: 'a' :  field selection requires structure or vector on left hand side
ERROR: 0:28: 'texture' : no matching overloaded function found
ERROR: 0:28: 'a' :  field selection requires structure or vector on left hand side
ERROR: 0:29: 'texture' : no matching overloaded function found
ERROR: 0:29: 'a' :  field selection requires structure or vector on left hand side
ERROR: 0:30: 'texture' : no matching overloaded function found
ERROR: 0:30: 'a' :  field selection requires structure or vector on left hand side
ERROR: 0:32: '' : No precision specified for (float)
ERROR: 0:33: '' : No precision specified for (float)

INFO: TEXTURE: [ID 13] Unloaded texture data from VRAM (GPU)
INFO: TEXTURE: [ID 12] Unloaded texture data from VRAM (GPU)
INFO: SHADER: [ID 5] Default shader unloaded successfully
INFO: TEXTURE: [ID 2] Default texture unloaded successfully
INFO: Window closed successfully
error: LoadShader
texture_outline
└─ run /Users/nii236/gamedev/emsdk/upstream/emscripten/emrun failure
error: the following command exited with error code 1:
/Users/nii236/gamedev/emsdk/upstream/emscripten/emrun zig-out/htmlout/index.html
Build Summary: 6/8 steps succeeded; 1 failed
texture_outline transitive failure
└─ run /Users/nii236/gamedev/emsdk/upstream/emscripten/emrun failure
error: the following build command failed with exit code 1:
/Users/nii236/gamedev/raylib-zig/.zig-cache/o/02825d3c8f32fd5ebe923c456607d91f/build /Users/nii236/.zvm/0.14.0/zig /Users/nii236/.zvm/0.14.0/lib /Users/nii236/gamedev/raylib-zig /Users/nii236/gamedev/raylib-zig/.zig-cache /Users/nii236/.cache/zig --seed 0x9ed2576c -Z4640f493333c3707 texture_outline -Dtarget=wasm32-emscripten --sysroot /Users/nii236/gamedev/emsdk/upstream/emscripten