private void Draw()
{
// update instance data
// NOTE: this is called here instead of in `Update` because buffers can only be updated once per frame
_instanceBuffer.Update(_positions.AsMemory().Slice(0, _currentParticleCount));
// begin a frame buffer render pass
var pass = BeginDefaultPass(Rgba32F.Black);
// describe the binding of the buffers
var resourceBindings = default(ResourceBindings);
resourceBindings.VertexBuffer() = _vertexBuffer;
resourceBindings.VertexBuffer(1) = _instanceBuffer;
resourceBindings.IndexBuffer = _indexBuffer;
// apply the render pipeline and bindings for the render pass
pass.ApplyPipeline(_pipeline);
pass.ApplyBindings(ref resourceBindings);
// apply the mvp matrix to the vertex shader
pass.ApplyShaderUniforms(ShaderStageType.VertexStage, ref _modelViewProjectionMatrix);
// draw the particles into the target of the render pass
pass.DrawElements(24, instanceCount: _currentParticleCount);
// end frame buffer render pass
pass.End();
}
