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Re: [Public WebGL] ESSL 3.5 Comments Compliance



I believe the validation also has to happen above ANGLE translator, as
we should raise an error in shaderSource(), whereas ANGLE translator
is only called in compileShader().

2011/1/14 Kenneth Russell <kbr@google.com>:
>
> 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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