Vertex Formats

The format of a vertex attribute indicates how data in a vertex buffer is laid out, and how it will exposed to the shader. Each format has a name that encodes

• the order of components
• bits per component
• and vertex data type for the component.

The VertexFormat type is a string union of all the defined vertex formats.

Vertex Format	Availability Check	WGSL types	GLSL Types	Notes
uint8	N/A	u32	uint	Chrome v133+
uint8x2	N/A	vec2<u32>	uvec2
uint8x4	N/A	vec2<u32>	uvec4
sint8	N/A	i32	int	Chrome v133+
sint8x2	N/A	vec2<i32>	ivec2
sint8x4	N/A	vec2<i32>	ivec4
unorm8	N/A	f16, f32	float	Chrome v133+
unorm8x2	N/A	vec2<f16>, vec2<f32>	vec2
unorm8x4	N/A	vec2<f16>, vec2<f32>	vec4
unorm8x4-bgra	N/A	vec4<f16>, vec4<f32>	❌	Chrome v133+
unorm10-10-10-2	N/A	vec4<f16>, vec4<f32>	❌	Chrome v119+
snorm8	N/A	f16, f32	float	Chrome v133+
snorm8x2	N/A	vec2<f16>, vec2<f32>	vec2
snorm8x4	N/A	vec2<f16>, vec2<f32>	vec4
uint16	N/A	u32	uint	Chrome v133+
uint16x2	N/A	vec2<u32>	ivec2
uint16x4	N/A	vec3<u32>	ivec4
sint16	N/A	i32	int	Chrome v133+
sint16x2	N/A	vec2<i32>	ivec2
sint16x4	N/A	vec2<i32>	ivec4
unorm16	N/A	f16, f32	float	Chrome v133+
unorm16x2	N/A	vec2<f16>, vec2<f32>	vec2
unorm16x4	N/A	vec3<f16>, vec4<f32>	vec4
snorm16	N/A	f16, f32	float	Chrome v133+
snorm16x2	N/A	vec2<f16>, vec2<f32>	vec2
snorm16x4	N/A	vec4<f16>, vec4<f32>	vec4
float16	N/A	f16, f32	❌	Chrome v133+
float16x2	N/A	vec2<f16>, vec2<f32>	❌
float16x4	N/A	vec4<f16>, vec4<f32>	❌
float32	N/A	f32	float
float32x2	N/A	vec2<f32	vec2
float32x3	N/A	vec3<f32	vec3
float32x4	N/A	vec4<f32	`vec4
uint32	N/A	u32	uint
uint32x2	N/A	vec2<u32>	uvec2
uint32x3	N/A	vec3<u32>	uvec3
uint32x4	N/A	vec4<u32>	uvec4
sint32	N/A	i32	int
sint32x2	N/A	vec2<i32>	ivec2
sint32x3	N/A	vec3<i32>	ivec3
sint32x4	N/A	vec4<i32>	ivec4

Shader Type mappings

Each vertex data type can map to any WGSL scalar type of the same base type, regardless of the bits per component:

Vertex format prefix	Vertex data type	Compatible WGSL types	Compatible GLSL types
uint	unsigned int	u32	uint, uvec2, uvec3, uvec4
sint	signed int	i32	int, ivec2, ivec3, ivec4
unorm	unsigned normalized	f16, f32	float, vec2, vec3, vec4
snorm	signed normalized	f16, f32	float, vec2, vec3, vec4
float16	floating point	f16, f32	float, vec2, vec3, vec4
float32	floating point	f32	float, vec2, vec3, vec4

GPU Backend Differences

luma.gl attempts to provide a consistent API across WebGPU and WebGL, but there are significant differences in vertex format supported across the two APIs.

• The multi-component formats specify the number of components after "x".
• Mismatches in the number of components between the vertex format and shader type are allowed, with components being either dropped or filled with default values to compensate.

When it comes to attributes, WebGPU is significantly more restrictive than WebGL:

Feature	WebGL	WebGPU	Comment
8-bit x1 alignment	✅	(✅)	WebGPU 8 bit integers must be aligned to 16, 32 bits (uint8x1, uint8x3, unorm8x1, unorm8x3 etc` are not supported)
8-bit x3 alignment	✅	❌	WebGPU 8 bit integers must be aligned to 8, 16, 32 bits (uint8x1, uint8x3, unorm8x1, unorm8x3 etc` are not supported)
16-bit x1 alignment	✅	(✅)	WebGPU 16 bit integers must be aligned to 32 bits (uint16x1, uint16x3, unorm16x1, unorm16x3 etc` are not supported)
16-bit x3 alignment	✅	❌	WebGPU 16 bit integers must be aligned to 32 bits (uint16x1, uint16x3, unorm16x1, unorm16x3 etc` are not supported)
Component mismatch	✅	(✅)	Use buffers with more or fewer components than expected by the shader (missing values will be filled with [0, 0, 0, 1]).
Normalized 32-bit integers	✅	❌	WebGPU 32 bit integer formats cannot be normalized
Per-attributestepMode	✅	❌	stepMode (WebGL: divisor, controls whether an attribute is instanced) can be set per-attribute, even when multiple attributes bind to the same buffer.
Per-attributebyteStride	✅	❌	byteStride (controls byte distance between two successive values in memory) can be set per-attribute, even when multiple attributes bind to the same buffer.
Dynamic VertexFormat	✅	❌	Buffers with different structure (different BufferLayout) can be provided without relinking the RenderPipeline
Constant attributes	✅	❌	(attribute locations can be disabled in which case a constant value is read from the WebGLRenderingContext)
Non-normalized integers	✅	❌	Non-normalized integer attributes can be assigned to floating point GLSL shader variables (e.g. vec4).

Presumably, the heavy restrictions in WebGPU are motivated by:

• portability across Vulkan/Metal/D3D12.
• additional optimizations during shader compilation
• reduced run-time validation overhead

In general, an argument can be made that in WebGPU / WGLS, attributes are less important since storage buffers are much more flexible, allowing arbitrary memory layouts, random access, and less limitations on number of bindings etc. Attributes may be faster than storage bindings, but at the moment there is no clear evidence that this is the case.

Notes:

• WebGPU: 8 and 16 bit formats only support 1, 2 or 4 components (only 2 or 4 components pre Chrome c133).
• WebGL: GLSL supports bool and bvec* but these are not portable to WebGPU and are not included by luma.gl.
• WebGL: GLSL types double and dvec* are not supported in any WebGL version (nor is f64 supported in WebGPU).