Add a mechanism for managing webgl extensions

• Should be able to report errors when extensions are missing
• Allow users to disable extensions for testing/mocking

Doc clean up

Add more test cases for regl.read() and improve validation

Implement a standard method for handling context creation errors

Fix several bugs related to regl.frame cancellation

Allow for dynamic properties in viewport, scissor box and attributes

Switch order of arguments to dynamic functions, from (props, context) to (context, props)

• functions without a props argument become batch static

Implement non-batch constant context, framebuffer and viewport

Batched scope rendering

Switch order of props and context variables for dynamic function args

function invocation now takes batch id as separate parameter

Support directly constructing elements and attributes from arrays

Allow individual attribute properties to be dynamic (eg buffers, offsets, etc.)

Code generation rewrite

• State flag polling is now inlined
• draw and batch inlined for static shaders
• constants are inlined
• fewer arguments passed to generated code
• Stop using separate arrays for stacks to manage state, instead state is saved onto the call stack

Error reporting

• All error messages should link to command/resource declaration
• Improve validation of vertex attributes
• Improve validation of dynamic properties

Code quality and contributing

• Combined lib/state.js and lib/compile.js into lib/core.js
• Delete most of lib/attribute.js
• Update development documentation

Expose limits for shader precision

Context variables

Use this argument effectively

• Should pass this to dynamic attributes and scope

Make scopes and dynamic attributes take same argument

Combine batchId with stats argument

Pass this to draw commands so that they can be stored as members