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Re: [Public WebGL] ESSL 3.5 Comments Compliance



Just a thought - is some care being taken to preserve line numbering
through this?

When errors are generated by the lower levels of
verification/compilation after comment stripping has happened, it's
important that they line up with the original code.

-- Steve


On 01/14/2011 09:45 PM, Kenneth Russell wrote:
> 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 Openshaders/cowboy_vs.glslGL 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shaders/cowboy_vs.glsl
>>>>> 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shaders/cowboy_vs.glsl
>>>>> 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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