[Bf-committers] GSOC Project: Real-time compositing / SSAO / Cavityshading

[Matthias Fauconneau]

my patch implements "a node that has an editable (text) property "GLSL code".
On the other hand, SSAO need a lot more work because it needs a depth
buffer. so you need to modify the GL rendering pipeline to allow
deferred shading.


On 3/20/10, Remo Pini <remo.pini at avexys.com> wrote:
> Would it be possible/feasible to extend this to support "GLSL Shader Nodes"?
> I.e. a node that has an editable (text) property "GLSL code"?
>
> I'm asking because I need to solve the problem of replicating the following
> GLSL logic in Blender and it seems a "GLSL Node" would do this nicely:
>
> ----------------------------
> uniform sampler2D Layer0;
> uniform sampler2D Layer1;
> uniform sampler2D Layer2;
> uniform sampler2D Layer3;
> uniform sampler2D Alpha1;
> uniform sampler2D Alpha2;
> uniform sampler2D Alpha3;
> varying vec4 texCoord;
>
> void main (void)
> {
>    vec4 l0 = texture2D( Layer0, texCoord.xy * 8);
>    vec4 l1 = texture2D( Layer1, texCoord.xy * 8);
>    vec4 l2 = texture2D( Layer2, texCoord.xy * 8);
>    vec4 l3 = texture2D( Layer3, texCoord.xy * 8);
>    vec4 a1 = texture2D( Alpha1, texCoord.xy);
>    vec4 a2 = texture2D( Alpha2, texCoord.xy);
>    vec4 a3 = texture2D( Alpha3, texCoord.xy);
>    gl_FragColor = l0 * (1 - a1.a - a2.a - a3.a) + l1 * a1.a + l2 * a2.a + l3
> * a3.a;
> }
>
> -----------------------------
>
> Of course a lot cooler features would be possible... the SSAO would then
> just be a more generic GLSL shader node with predefined code (I'm dreaming
> of a drop down of predefined GLSL fragment shader types that would populate
> the GLSL code text).
>
> Wishfull thinking?
>
> Cheers
>
> Remo
>
>> -----Original Message-----
>> From: bf-committers-bounces at blender.org [mailto:bf-committers-
>> bounces at blender.org] On Behalf Of Matthias Fauconneau
>> Sent: Samstag, 20. März 2010 3:24
>> To: bf-committers at blender.org
>> Subject: [Bf-committers] GSOC Project: Real-time compositing / SSAO /
>> Cavityshading
>>
>> Synopsis:
>> Cavity shading is an effect which allows artists to better perceive
>> bump and valleys on their objects. This effect can be computed in
>> real-time using Screen-Space Ambient Occlusion.
>> By extending the existing compositing nodes to support GLSL
>> compositing in the viewport, Blender could win three features in one.
>>
>> Benefits to Blender:
>> Cavity shading is requested by blender sculptors and modelers on
>> blenderartists.org and IRC. It is also on the Durian wishlist.
>> SSAO can also be used as an approximate AO for rendering and in game
>> engine.
>> GLSL compositing would help preview compositing effects and may
>> eventually be used to accelerate render.
>>
>> Deliverables:
>> 3D View will support compositing effect.
>> Compositing node will be translated to GLSL.
>> A custom compositing node will compute SSAO.
>> Deferred material like Cavity shading will become possible.
>>
>> Project Details:
>> The first step is to interface with the 3D View to create a
>> framebuffer and render with effects applied.
>> Building upon the GLSL material nodes (in blender/gpu/), It is
>> possible to translate the compositing node graphs into GLSL code.
>> The SSAO shader was already implemented as a compositing node[1]. It
>> was translated to C from a GLSL implementation. with GLSL compositing
>> nodes, the original shader can be used.
>> Finally, the cavity shader is simply a mapping of AO values to a color
>> ramp. Some work will have to be done to support multiple materials.
>>
>> Bio:
>> I'm a 18 year old student in my 1st licence year in physics, at
>> Université Paris-Sud 11
>> My main interest is real-time computer graphics.
>> I know how to use blender but I am no 3D artist.
>> I coded small projects like a quake3 .map renderer, a 2D platformer
>> with softbody physics and a comic coloring software.
>>
>> Patch:
>> I implemented a GLSL material node allowing the user to write it's own
>> GLSL shader.
>> This allowed me to get to know part of blender architecture.
>> screenshot -> http://imagebin.org/89652
>> patch -> http://pastebin.com/Q07TQn3F
>>
>> PS: I'll be on #blendercoders as "Matthias-" for the Sunday IRC Meeting
>>
>> [1] CPU SSAO compositing node by arkano22:
>>        thread: http://blenderartists.org/forum/showthread.php?t=175863
>>        patch: http://www.thehiddenfactory.com/arkano/cavityao.patch
>> _______________________________________________
>> Bf-committers mailing list
>> Bf-committers at blender.org
>> http://lists.blender.org/mailman/listinfo/bf-committers
> _______________________________________________
> Bf-committers mailing list
> Bf-committers at blender.org
> http://lists.blender.org/mailman/listinfo/bf-committers
>