BabylonJS/Babylon.js · error · Error

"The glsl file must contain a header comment with a smartFil

Error message

"The glsl file must contain a header comment with a smartFilterBlockType value"

What it means

ConvertGlslIntoBlock requires every block .glsl fragment shader to carry a header comment declaring a smartFilterBlockType value, which the build tool uses to name/generate the block class. If ExtractShaderProgramFromGlsl finds no blockType in the header, conversion fails with this error.

Source

Thrown at packages/dev/smartFilters/src/utils/buildTools/convertGlslIntoBlock.ts:165

}

`;

/**
 * Converts a single shader to a .ts file which exports a Smart Filter block
 * @param fragmentShaderPath - The path to the fragment file for the shader
 * @param smartFiltersCorePath - The path to import the Smart Filters core from
 * @param babylonCorePath - The path to import the Babylon core from (optional)

 */
export function ConvertGlslIntoBlock(fragmentShaderPath: string, smartFiltersCorePath: string, babylonCorePath?: string): void {
    const extraImports: string[] = [];

    const { shaderProgramCode, fragmentShaderInfo } = ExtractShaderProgramFromGlsl(fragmentShaderPath, smartFiltersCorePath, false, false);

    // Validation
    if (!fragmentShaderInfo.blockType) {
        throw new Error("The glsl file must contain a header comment with a smartFilterBlockType value");
    }

    // Generate shader binding private variables
    const shaderBindingPrivateVariables = fragmentShaderInfo.uniforms
        .map((uniform) => {
            return uniform.properties?.autoBind
                ? null
                : ShaderBindingPrivateVariablesTemplate.replace(CAMEL_CASE_UNIFORM, uniform.name).replace(CONNECTION_POINT_TYPE, GetConnectionPointTypeString(uniform.type));
        })
        .filter((line) => line !== null);

    // Generate the shader binding constructor docstring params
    const shaderBindingCtorDocstringParams = fragmentShaderInfo.uniforms
        .map((uniform) => {
            return uniform.properties?.autoBind ? null : ShaderBindingCtorDocstringParams.replace(new RegExp(CAMEL_CASE_UNIFORM, "g"), uniform.name);
        })
        .filter((param) => param !== null);

View on GitHub (pinned to 0592b347b8)

Solutions

1. Add a header comment with smartFilterBlockType at the top of the glsl file.
2. Check spelling/case of smartFilterBlockType in the header comment.
3. Verify the file is the fragment shader and was parsed by ExtractShaderProgramFromGlsl (correct path passed).

Example fix

// before
// A simple blur block
uniform float textureWidth;
// after
// smartFilterBlockType: blur
// A simple blur block
uniform float textureWidth;

/^\s*\/\/\s*smartFilterBlockType:\s*[\w-]+/m.test(fs.readFileSync(glslPath, 'utf8')) || console.error(`${glslPath} missing smartFilterBlockType header`);

try { await ConvertShader(path, ...); } catch (e) { if (e.message.includes('smartFilterBlockType')) { fixShaderHeader(path); } else { throw e; } }

When it happens

Trigger: Converting a .fragment.glsl / .block.glsl file whose header comment lacks the smartFilterBlockType annotation (e.g. a header comment like '// smartFilterBlockType: myBlock').

Common situations: Hand-written glsl files created without the required header; header removed during editing; typo in the annotation name; third-party shader converted without adding the header.

Related errors

• "A block that uses a BlockDisableStrategy other than Manual
• "The shader file must end with .fragment.glsl or .block.glsl
• "Const line not found"
• VERTEX SHADER ${log}
• FRAGMENT SHADER ${log}

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/1eff954c844870b1. Report an issue: GitHub.