[Bf-viewport] OpenGL low level shader API proposal

[Jacob Merrill]

there* (sorry spelling*)

On Sat, Dec 5, 2015 at 4:38 PM, Jacob Merrill <blueprintrandom1 at gmail.com>
wrote:

> would this new viewport also modify the material system?
>
> PBR an NPR workflow?
>
> and obligatory - Will this render bge usable by the bge? will it
> boost performance their also?
>
>
> On Sat, Dec 5, 2015 at 3:34 PM, Mike Erwin <significant.bit at gmail.com>
> wrote:
>
>> Yes, thank you! Interesting stuff. Here's my first round of notes:
>>
>> +1 for immutable draw state.
>> +100 for minimizing state changes! Marry desired state to the draw call.
>>
>> Re: Uniform Buffer Objects -- Compatibility with GL 2.1 is a temporary
>> concern, so anything we do there should be minimal and marked for future
>> removal.
>>
>> For passing in the current transformation, I don't think the lowest-level
>> API should treat this or any other inputs special. Do like the convenience
>> of not having to specify CTM every time though... maybe I'm on the fence
>> about this one! Since a lot of this has to do with UI drawing, how about a
>> dedicated 2D transformation system, stack or otherwise? See bottom part of:
>> http://wiki.blender.org/index.php/Dev:2.8/Source/OpenGL/Transformations
>> 3D shaders would automatically get a 3x4 ModelView and 4x4 Projection
>> matrix, maybe a 4x4 MVP for efficiency. 2D shaders would automatically get
>> a 2x3 ModelView matrix and that's it.
>>
>>
>> Some basic assumptions, definitions, questions... please let me know if
>> any of these are way off:
>>
>> GPUShader is a compiled & linked set of Vertex shader, optional Geometry
>> shader, and Fragment shader.
>>
>> Inputs for the GPUShader are the active uniforms (which could be from any
>> of the above shader stages) and vertex attributes from the first stage.
>>
>> Uniform values are set once per draw. Attribute values are typically set
>> per vertex from data in VBOs. Attributes can also be set once per draw
>> using glVertexAttrib, acting more like uniforms from client program's point
>> of view.
>>
>> Uniforms can have default values in GLSL. Is there any way to query the
>> program to see if an input *requires* us to set a value? Beyond parsing the
>> GLSL source text.
>>
>> Anyone interested in parsing GLSL source text?
>>
>>
>> Mike Erwin
>> musician, naturalist, pixel pusher, hacker extraordinaire
>>
>> _______________________________________________
>> Bf-viewport mailing list
>> Bf-viewport at blender.org
>> http://lists.blender.org/mailman/listinfo/bf-viewport
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.blender.org/pipermail/bf-viewport/attachments/20151205/d9595700/attachment.htm