files/en-us/web/api/gpurenderpassencoder/setblendconstant/index.md
{{APIRef("WebGPU API")}}{{SecureContext_Header}}{{AvailableInWorkers}}
The setBlendConstant() method of the
{{domxref("GPURenderPassEncoder")}} interface sets the constant blend color and alpha values used with "constant" and "one-minus-constant" blend factors (as set in the descriptor of the {{domxref("GPUDevice.createRenderPipeline()")}} method, in the blend property).
setBlendConstant(color)
color
: An object or array representing the color to use when blending — the r, g, b, and a components are represented as floating point numbers between 0.0 and 1.0.
What follows is an object example:
const color = { r: 0.0, g: 0.5, b: 1.0, a: 1.0 };
The array equivalent would look like this:
const color = [0.0, 0.5, 1.0, 1.0];
[!NOTE] If a
setBlendConstant()call is not made, the blend constant color value defaults to(0, 0, 0, 0)for each render pass.
None ({{jsxref("Undefined")}}).
// …
const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);
passEncoder.setPipeline(renderPipeline);
passEncoder.setVertexBuffer(0, vertexBuffer);
passEncoder.setBlendConstant([1.0, 0.0, 0.0, 1.0]);
passEncoder.draw(3);
passEncoder.end();
// …
{{Specifications}}
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