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Re: [Public WebGL] ESSL 3.5 Comments Compliance



On Fri, Jan 14, 2011 at 7:04 PM, Vladimir Vukicevic
<vladimir@mozilla.com> wrote:
>
>
> ----- Original Message -----
>> On Thu, Jan 13, 2011 at 5:35 PM, Kenneth Russell <kbr@google.com>
>> wrote:
>> > I agree with you. With a little preprocessing at the browser layer
>> > before handing down a const char* to the OpenGL layer (be it the
>> > ANGLE
>> > shader translator or OpenGL directly), a WebGL implementation should
>> > be able to allow the entire Unicode character range to be used in
>> > comments by stripping them completely. I don't think we need to
>> > reference UTF-8, since DOMStrings come in in (not necessarily valid)
>> > UTF-16. See http://dev.w3.org/2006/webapi/WebIDL/#idl-DOMString .
>> >
>> > Can you either propose some spec text or just edit the spec
>> > directly?
>>
>> I've gone ahead and updated the WebGL spec to require that the full
>> Unicode character set can be used in comments in shaders, and updated
>> the glsl-conformance.html test to ensure both this and that non-ASCII
>> characters in the actual shader text is rejected. Please send any
>> comments to the list.
>
> Sounds great to me -- Ken, is the plan to have ANGLE just strip comments and verify that the remainder is ASCII (or the limited subset thereof)?  Or would we have to do that at a level before the shader translator?

I believe the removal of comments must be done at a level above the
shader translator. The browser takes in DOMStrings containing
potentially invalid UTF-16 data, and before the conversion to either
ASCII or UTF-8 it needs to strip the comments potentially containing
non-ASCII characters. We should modify ANGLE to enforce that the
incoming const char* is not only ASCII but also fully ESSL compliant,
though in the WebKit implementation that is currently being done at
the browser level.

I'm about to upload a patch for
https://bugs.webkit.org/show_bug.cgi?id=52390 implementing the removal
of comments. The WebGL conformance suite has already been updated for
the new rules.

-Ken

>    - Vlad
>
>> > On Thu, Jan 13, 2011 at 4:49 PM, Gregg Tavares (wrk)
>> > <gman@google.com> wrote:
>> >> I really want to emphasize that it would be really insensitive to
>> >> make WebGL
>> >> only support ASCII in comments in shaders. It's called WebGL
>> >> because it's on
>> >> the WEB and the WEB is not ASCII. I know the OpenGL spec says
>> >> ASCII. I have
>> >> a feeling though few if any drivers enforce that and like I
>> >> mentioned
>> >> before, even if they do enforce it WebGL implementations can work
>> >> around it
>> >> by stripping the comments.
>> >> Imagine someone told you couldn't document your code in a language
>> >> you
>> >> understand. How would you feel? Imagine if you couldn't even write
>> >> a blog
>> >> post that showed sample code with inline comments or that if you
>> >> put inline
>> >> comments in users trying to copy and paste snippets from your
>> >> tutorial had
>> >> to manually remove all the inline comments.
>> >> Seriously, it seems morally wrong in 2011 to force programmers the
>> >> world
>> >> over to ASCII only for their shader comments.
>> >> Here's a shader from this page
>> >> WebGL MQO Loader
>> >> Are we really going to tell that guy he has to learn English if he
>> >> wants to
>> >> document his code?
>> >> I think we should diverge from the OpenGL ES spec here in the
>> >> interest of
>> >> the needs of the Web and the world at large. Checking for valid
>> >> UTF8 is easy
>> >> if we want to validate input and workarounds past that are probably
>> >> not
>> >> needed and even if they are probably very easy. The ANGLE
>> >> translator already
>> >> strips comments as far as I know so just validating UTF8 and
>> >> calling the
>> >> translator is enough to allow WebGL to be an international
>> >> developer
>> >> friendly standard.
>> >>
>> >> ---------------------------
>> >> #ifdef GL_ES
>> >> precision highp float;
>> >> #endif
>> >> //VertexShader
>> >> //入力パラメータ
>> >> attribute vec3 aVertexPosition; //入力位置
>> >> attribute vec3 aVertexNormal; //入力法線
>> >> attribute vec3 aVertexTangent; //入力法線
>> >> attribute vec3 aVertexBinormal; //入力法線
>> >> attribute vec4 aVertexColor; //入力カラー
>> >> attribute vec2 aTextureCoord; //入力UV
>> >> //出力パラメータ
>> >> varying vec4 vColor; //出力カラー
>> >> varying vec2 vTextureCoord; //出力UV
>> >> varying vec3 vNormal; //出力法線
>> >> varying vec3 vTangent; //出力接線
>> >> varying vec3 vBinormal; //出力従法線
>> >> varying vec3 vLightDir; //出力ライト
>> >> varying vec3 vEyeDir; //出力視線
>> >> varying vec4 vShadowMap; //出力シャドウマップ位置
>> >> //固定パラメータ
>> >> uniform mat4 WorldMatrix; //ワールドマトリクス
>> >> uniform mat4 ViewMatrix; //ビューマトリクス
>> >> uniform mat4 ProjMatrix; //プロジェクションマトリクス
>> >> uniform mat4 SMapLightMatrix; //シャドウマップライトマトリクス
>> >> //
>> >> uniform bool use_dif_texture; //ディフューズテクスチャ使用
>> >> uniform bool use_alpha_texture; //アルファテクスチャ使用
>> >> uniform bool use_celsdif_texture; //ディフューズセルシェーダテクスチャ使用
>> >> uniform bool use_celsspc_texture; //スペキュラセルシェーダテクスチャ使用
>> >> uniform bool use_reflec_texture; //リフレクションテクスチャ使用
>> >> uniform bool use_bump_texture; //バンプテクスチャ使用
>> >> uniform bool use_smap_texture; //シャドウマップテクスチャ使用
>> >> uniform bool use_light; //ライティング使用
>> >> uniform bool use_edge; //エッジ使用
>> >> uniform bool draw_smap_flg; //シャドウマップ描画
>> >> //
>> >> uniform vec3 light_dir; //ライト方向
>> >> uniform vec3 g_ViewDir; //エッジ色
>> >> uniform float edge_scale; //エッジスケール
>> >> mat3 transpose_mat3(mat3 mt){
>> >> mat3 mt2;
>> >> mt2[0][0]=mt[0][0];
>> >> mt2[0][1]=mt[1][0];
>> >> mt2[0][2]=mt[2][0];
>> >> mt2[1][0]=mt[0][1];
>> >> mt2[1][1]=mt[1][1];
>> >> mt2[1][2]=mt[2][1];
>> >> mt2[2][0]=mt[0][2];
>> >> mt2[2][1]=mt[1][2];
>> >> mt2[2][2]=mt[2][2];
>> >> return mt2;
>> >> }
>> >> void main(void) {
>> >> vec3 now_pos=aVertexPosition;
>> >> if(use_edge){
>> >> now_pos+=(aVertexNormal*edge_scale);
>> >> }
>> >> mat4 WorldMatrixView=ViewMatrix * WorldMatrix;
>> >> vec3 dpos2 =(WorldMatrixView * vec4(now_pos,1.0)).xyz;
>> >> gl_Position = ProjMatrix * vec4(dpos2,1.0);
>> >> if(use_dif_texture || use_alpha_texture || use_bump_texture){
>> >> vTextureCoord = aTextureCoord;
>> >> }else{
>> >> vTextureCoord = vec2(0.0,0.0);
>> >> }
>> >> if(draw_smap_flg){
>> >> vShadowMap=vec4(gl_Position);
>> >> }else{
>> >> if(use_smap_texture){
>> >> vShadowMap=SMapLightMatrix * vec4(dpos2,1.0);
>> >> }
>> >> }
>> >> //
>> >> vColor = aVertexColor;
>> >> //
>> >> mat3 nmt=mat3(WorldMatrix);
>> >> vec3 norm=normalize(nmt*aVertexNormal);
>> >> vNormal=norm;
>> >> //
>> >> if(use_bump_texture){
>> >> vec3 tangent=normalize(nmt*aVertexTangent);
>> >> vec3 binorm =normalize(nmt*aVertexBinormal);
>> >> mat3 tan_mt=mat3(tangent,binorm,norm);
>> >> // tan_mt=transpose(tan_mt);
>> >> tan_mt=transpose_mat3(tan_mt);
>> >> vTangent =tangent;
>> >> vBinormal=binorm;
>> >> vLightDir=tan_mt*light_dir;
>> >> vEyeDir =tan_mt*g_ViewDir;
>> >> }else{
>> >> vLightDir=light_dir;
>> >> vEyeDir =g_ViewDir;
>> >> }
>> >> }
>> >>
>> >
>
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