API Reference > imodeljs-frontend > Rendering > ScreenSpaceEffectSource > vertex vertex vertex: string The GLSL implementation of the vertex shader. Instead of main, it implements void effectMain(vec4 position) where position is the vertex position in normalized device coordinates ([-1..1]). effectMain should compute whatever information is required by the fragment shader. It should not assign to gl_Position. Defined in core/frontend/src/render/ScreenSpaceEffectBuilder.ts Line 112 Last Updated: 11 June, 2024