Revert "Implement EXT_shader_texture_lod"

extensions/EXT_shader_texture_lod.txt

-Name
-
-    EXT_shader_texture_lod
-
-Name Strings
-
-    GL_EXT_shader_texture_lod
-
-Contributors
-
-    Benj Lipchak
-    Ben Bowman
-
-    and contributors to the ARB_shader_texture_lod spec, 
-    which provided the basis for this spec.
-
-Contact
-
-    Benj Lipchak, Apple (lipchak 'at' apple.com)
-
-IP Status
-
-    No known IP issues.
-
-Status
-
-    Draft
-
-Version
-
-    Last Modified Date: February 24, 2011
-    Revision: 3
-
-Number
-
-    OpenGL ES Extension #77
-
-Dependencies
-
-    This extension is written against the OpenGL ES 2.0 Specification.
-
-    This extension is written against The OpenGL ES Shading Language,
-    Language Version 1.00, Document Revision 17.
-
-    This extension interacts with EXT_texture_filter_anisotropic.
-
-Overview
-
-    This extension adds additional texture functions to the
-    OpenGL ES Shading Language which provide the shader writer
-    with explicit control of LOD.
-
-    Mipmap texture fetches and anisotropic texture fetches
-    require implicit derivatives to calculate rho, lambda
-    and/or the line of anisotropy.  These implicit derivatives
-    will be undefined for texture fetches occurring inside
-    non-uniform control flow or for vertex shader texture
-    fetches, resulting in undefined texels.
-
-    The additional texture functions introduced with
-    this extension provide explicit control of LOD
-    (isotropic texture functions) or provide explicit
-    derivatives (anisotropic texture functions).
-
-    Anisotropic texture functions return defined texels
-    for mipmap texture fetches or anisotropic texture fetches,
-    even inside non-uniform control flow.  Isotropic texture
-    functions return defined texels for mipmap texture fetches,
-    even inside non-uniform control flow.  However, isotropic
-    texture functions return undefined texels for anisotropic
-    texture fetches.
-
-    The existing isotropic vertex texture functions:
-
-        vec4 texture2DLodEXT(sampler2D sampler,
-                             vec2 coord, 
-                             float lod);
-        vec4 texture2DProjLodEXT(sampler2D sampler,
-                                 vec3 coord, 
-                                 float lod);
-        vec4 texture2DProjLodEXT(sampler2D sampler,
-                                 vec4 coord, 
-                                 float lod);
-
-        vec4 textureCubeLodEXT(samplerCube sampler,
-                               vec3 coord,
-                               float lod);
-
-    are added to the built-in functions for fragment shaders
-    with "EXT" suffix appended.
-
-    New anisotropic texture functions, providing explicit
-    derivatives:
-
-        vec4 texture2DGradEXT(sampler2D sampler,
-                              vec2 P, 
-                              vec2 dPdx, 
-                              vec2  dPdy);
-        vec4 texture2DProjGradEXT(sampler2D sampler,
-                                  vec3 P, 
-                                  vec2 dPdx, 
-                                  vec2 dPdy);
-        vec4 texture2DProjGradEXT(sampler2D sampler,
-                                  vec4 P,
-                                  vec2 dPdx, 
-                                  vec2 dPdy);
-
-        vec4 textureCubeGradEXT(samplerCube sampler,
-                                vec3 P,
-                                vec3 dPdx, 
-                                vec3 dPdy);
-
-     are added to the built-in functions for vertex shaders
-     and fragment shaders.
-
-New Procedures and Functions
-
-    None
-
-New Tokens
-
-    None
-
-Additions to Chapter 2 of the OpenGL ES 2.0 Specification (OpenGL Operation)
-
-    None
-
-Additions to Chapter 3 of the OpenGL ES 2.0 Specification (Rasterization)
-
-    In Section 3.7.7, replace the final paragraph on p. 76 with:
-
-    "Let s(x, y) be the function that associates an s texture coordinate
-    with each set of window coordinates (x, y) that lie within a
-    primitive;  define t(x, y) analogously.  Let u(x, y) = wt * s(x, y) and 
-    v(x, y) = ht * t(x, y), where wt and ht are equal to the width and height 
-    of the level zero array.
-
-    Let
-        dUdx = wt*dSdx; dUdy = wt*dSdy;
-        dVdx = ht*dTdx; dVdy = ht*dTdy;                       (3.12a)
-
-    where dSdx indicates the derivative of s with respect to window x,
-    and similarly for dTdx.
-
-    For a polygon, rho is given at a fragment with window coordinates
-    (x, y) by
-
-        rho = max (
-              sqrt(dUdx*dUdx + dVdx*dVdx),
-              sqrt(dUdy*dUdy + dVdy*dVdy)
-              );                                              (3.12b)"
-
-Additions to Chapter 4 of the OpenGL ES 2.0 Specification (Per-Fragment Operations and the Frame Buffer)
-
-    None
-
-Additions to Chapter 5 of the OpenGL ES 2.0 Specification (Special Functions)
-
-    None
-
-Additions to Chapter 6 of the OpenGL ES 2.0 Specification (State and State
-Requests)
-
-    None
-
-Additions to Appendix A of the OpenGL ES 2.0 Specification (Invariance)
-
-    None
-
-Additions to version 1.00.17 of the OpenGL ES Shading Language Specification
-
-    "A new preprocessor #define is added to the OpenGL Shading Language:
-
-        #define GL_EXT_shader_texture_lod 1
-
-    Including the following line in a shader can be used to control the
-    language features described in this extension:
-
-        #extension GL_EXT_shader_texture_lod : <behavior>
-
-    Where <behavior> is as specified in section 3.3."
-
-
-Additions to Chapter 8 of version 1.00.17 of the OpenGL ES Shading Language
-Specification
-
-
-    8.7  Texture Lookup Functions
-
-    Delete the last paragraph, and replace with:
-
-    "For the "Lod" functions, lod specifies lambda_base (see equation 3.11 in
-    The OpenGL ES 2.0 Specification) and specifies dSdx, dTdx = 0 and
-    dSdy, dTdy = 0 (see equation 3.12a in The OpenGL ES 2.0 Specification).
-    The "Lod" functions are allowed in a vertex shader.  If enabled by the 
-    preprocessor directive #extension, the "Lod" functions are also allowed in 
-    a fragment shader.
-
-    For the "Grad" functions, dPdx is the explicit derivative of P with respect
-    to window x, and similarly dPdy with respect to window y. For the "ProjGrad"
-    functions, dPdx is the explicit derivative of the projected P with respect
-    to window x, and similarly for dPdy with respect to window y.  For a two-
-    dimensional texture, dPdx and dPdy are vec2.  For a cube map texture, 
-    dPdx and dPdy are vec3.
-
-    Let
-
-        dSdx = dPdx.s;
-        dSdy = dPdy.s;
-        dTdx = dPdx.t;
-        dTdy = dPdy.t;
-
-    and
-
-                / 0.0;    for two-dimensional texture
-        dRdx = (
-                \ dPdx.p; for cube map texture
-
-                / 0.0;    for two-dimensional texture
-        dRdy = (
-                \ dPdy.p; for cube map texture
-
-    (See equation 3.12a in The OpenGL ES 2.0 Specification.)
-
-    If enabled by the preprocessor directive #extension, the "Grad" functions
-    are allowed in vertex and fragment shaders.
-
-    All other texture functions may require implicit derivatives.  Implicit
-    derivatives are undefined within non-uniform control flow or for vertex
-    shader texture fetches."
-
-    Add the following entries to the texture function table:
-
-        vec4 texture2DGradEXT(sampler2D sampler,
-                              vec2 P, 
-                              vec2 dPdx, 
-                              vec2  dPdy);
-        vec4 texture2DProjGradEXT(sampler2D sampler,
-                                  vec3 P, 
-                                  vec2 dPdx, 
-                                  vec2 dPdy);
-        vec4 texture2DProjGradEXT(sampler2D sampler,
-                                  vec4 P,
-                                  vec2 dPdx, 
-                                  vec2 dPdy);
-
-        vec4 textureCubeGradEXT(samplerCube sampler,
-                                vec3 P,
-                                vec3 dPdx, 
-                                vec3 dPdy);
-
-Interactions with EXT_texture_anisotropic
-
-    The Lod functions set the derivatives ds/dx, dt/dx, dr/dx,
-    dx/dy, dt/dy, and dr/dy = 0.  Therefore Rhox and Rhoy = 0
-    0, Rhomax and Rhomin = 0.
-
-Revision History:
-
-3 - 2011-02-24
-    * Assign extension number
-
-2 - 2010-01-20
-    * Naming updates
-
-1 - 2010-01-19
-    * Initial ES version

include/GLSLANG/ShaderLang.h

@@ -256,7 +256,6 @@ typedef struct
     int ARB_texture_rectangle;
     int EXT_draw_buffers;
     int EXT_frag_depth;
-    int EXT_shader_texture_lod;
 
     // Set to 1 if highp precision is supported in the fragment language.
     // Default is 0.

samples/translator/translator.cpp

@@ -126,7 +126,6 @@ int main(int argc, char* argv[])
                     case 'i': resources.OES_EGL_image_external = 1; break;
                     case 'd': resources.OES_standard_derivatives = 1; break;
                     case 'r': resources.ARB_texture_rectangle = 1; break;
-                    case 'l': resources.EXT_shader_texture_lod = 1; break;
                     default: failCode = EFailUsage;
                     }
                 } else {
@@ -232,8 +231,7 @@ void usage()
         "       -b=h11   : output HLSL11 code\n"
         "       -x=i     : enable GL_OES_EGL_image_external\n"
         "       -x=d     : enable GL_OES_EGL_standard_derivatives\n"
-        "       -x=r     : enable ARB_texture_rectangle\n"
-        "       -x=l     : enable EXT_shader_texture_lod\n");
+        "       -x=r     : enable ARB_texture_rectangle\n");
 }
 
 //

src/compiler/translator/Initialize.cpp

@@ -350,22 +350,6 @@ void InsertBuiltInFunctions(ShShaderType type, ShShaderSpec spec, const ShBuiltI
         symbolTable.insertBuiltIn(float4, "texture2DRectProj", sampler2DRect, float4);
     }
 
-    if (resources.EXT_shader_texture_lod)
-    {
-        /* The *Grad* variants are new to both vertex and fragment shaders; the fragment
-         * shader specific pieces are added separately belyw
-         * added separately below.
-         */
-        symbolTable.insertBuiltIn(float4, "texture2DGradEXT", sampler2D, float2, float2, float2);
-        symbolTable.insertBuiltIn(float4, "texture2DProjGradEXT", sampler2D, float3, float2, float2);
-        symbolTable.insertBuiltIn(float4, "texture2DProjGradEXT", sampler2D, float4, float2, float2);
-        symbolTable.insertBuiltIn(float4, "textureCubeGradEXT", samplerCube, float3, float3, float3);
-
-        symbolTable.relateToExtension("texture2DGradEXT", "GL_EXT_shader_texture_lod");
-        symbolTable.relateToExtension("texture2DProjGradEXT", "GL_EXT_shader_texture_lod");
-        symbolTable.relateToExtension("textureCubeGradEXT", "GL_EXT_shader_texture_lod");
-    }
-
     if (type == SH_FRAGMENT_SHADER)
     {
         symbolTable.insertBuiltIn(float4, "texture2D", sampler2D, float2, float1);
@@ -390,21 +374,9 @@ void InsertBuiltInFunctions(ShShaderType type, ShShaderSpec spec, const ShBuiltI
             symbolTable.insertBuiltIn(float3, "fwidth", float3);
             symbolTable.insertBuiltIn(float4, "fwidth", float4);
         }
-
-        if (resources.EXT_shader_texture_lod)
-        {
-            symbolTable.insertBuiltIn(float4, "texture2DLodEXT", sampler2D, float2, float1);
-            symbolTable.insertBuiltIn(float4, "texture2DProjLodEXT", sampler2D, float3, float1);
-            symbolTable.insertBuiltIn(float4, "texture2DProjLodEXT", sampler2D, float4, float1);
-            symbolTable.insertBuiltIn(float4, "textureCubeLodEXT", samplerCube, float3, float1);
-
-            symbolTable.relateToExtension("texture2DLodEXT", "GL_EXT_shader_texture_lod");
-            symbolTable.relateToExtension("texture2DProjLodEXT", "GL_EXT_shader_texture_lod");
-            symbolTable.relateToExtension("textureCubeLodEXT", "GL_EXT_shader_texture_lod");
-        }
     }
 
-    if (type == SH_VERTEX_SHADER)
+    if(type == SH_VERTEX_SHADER)
     {
         symbolTable.insertBuiltIn(float4, "texture2DLod", sampler2D, float2, float1);
         symbolTable.insertBuiltIn(float4, "texture2DProjLod", sampler2D, float3, float1);
@@ -589,6 +561,4 @@ void InitExtensionBehavior(const ShBuiltInResources& resources,
         extBehavior["GL_EXT_draw_buffers"] = EBhUndefined;
     if (resources.EXT_frag_depth)
         extBehavior["GL_EXT_frag_depth"] = EBhUndefined;
-    if (resources.EXT_shader_texture_lod)
-        extBehavior["GL_EXT_shader_texture_lod"] = EBhUndefined;
 }

src/compiler/translator/OutputGLSL.cpp

@@ -33,24 +33,3 @@ void TOutputGLSL::visitSymbol(TIntermSymbol* node)
         TOutputGLSLBase::visitSymbol(node);
     }
 }
-
-TString TOutputGLSL::translateTextureFunction(TString& name)
-{
-    static const char *simpleRename[] = {
-        "texture2DLodEXT", "texture2DLod",
-        "texture2DProjLodEXT", "texture2DProjLod",
-        "textureCubeLodEXT", "textureCubeLod",
-        "texture2DGradEXT", "texture2DGradARB",
-        "texture2DProjGradEXT", "texture2DProjGradARB",
-        "textureCubeGradEXT", "textureCubeGradARB",
-        NULL, NULL
-    };
-
-    for (int i = 0; simpleRename[i] != NULL; i += 2) {
-        if (name == simpleRename[i]) {
-            return simpleRename[i+1];
-        }
-    }
-
-    return name;
-}

src/compiler/translator/OutputGLSL.h

@@ -21,7 +21,6 @@ public:
 protected:
     virtual bool writeVariablePrecision(TPrecision);
     virtual void visitSymbol(TIntermSymbol* node);
-    virtual TString translateTextureFunction(TString& name);
 };
 
 #endif  // CROSSCOMPILERGLSL_OUTPUTGLSL_H_

src/compiler/translator/OutputGLSLBase.cpp

@@ -798,9 +798,8 @@ TString TOutputGLSLBase::hashVariableName(const TString& name)
 TString TOutputGLSLBase::hashFunctionName(const TString& mangled_name)
 {
     TString name = TFunction::unmangleName(mangled_name);
-    if (mSymbolTable.findBuiltIn(mangled_name) != NULL || name == "main") {
-        return translateTextureFunction(name);
-    }
+    if (mSymbolTable.findBuiltIn(mangled_name) != NULL || name == "main")
+        return name;
     return hashName(name);
 }
 

src/compiler/translator/OutputGLSLBase.h

@@ -50,8 +50,6 @@ protected:
     TString hashVariableName(const TString& name);
     // Same as hashName(), but without hashing built-in functions.
     TString hashFunctionName(const TString& mangled_name);
-    // Used to translate function names for differences between ESSL and GLSL
-    virtual TString translateTextureFunction(TString& name) { return name; }
 
 private:
     bool structDeclared(const TStructure* structure) const;

src/compiler/translator/OutputHLSL.h

@@ -93,12 +93,9 @@ class OutputHLSL : public TIntermTraverser
     bool mUsesTexture2DProj;
     bool mUsesTexture2DProj_bias;
     bool mUsesTexture2DProjLod;
-    bool mUsesTexture2DGrad;
-    bool mUsesTexture2DProjGrad;
     bool mUsesTextureCube;
     bool mUsesTextureCube_bias;
     bool mUsesTextureCubeLod;
-    bool mUsesTextureCubeGrad;
     bool mUsesTexture2DLod0;
     bool mUsesTexture2DLod0_bias;
     bool mUsesTexture2DProjLod0;

src/compiler/translator/ShaderLang.cpp

@@ -89,7 +89,6 @@ void ShInitBuiltInResources(ShBuiltInResources* resources)
     resources->ARB_texture_rectangle = 0;
     resources->EXT_draw_buffers = 0;
     resources->EXT_frag_depth = 0;
-    resources->EXT_shader_texture_lod = 0;
 
     // Disable highp precision in fragment shader by default.
     resources->FragmentPrecisionHigh = 0;

src/compiler/translator/SymbolTable.h

@@ -280,7 +280,7 @@ public:
         return insert(*constant);
     }
 
-    bool insertBuiltIn(TType *rvalue, const char *name, TType *ptype1, TType *ptype2 = 0, TType *ptype3 = 0, TType *ptype4 = 0)
+    bool insertBuiltIn(TType *rvalue, const char *name, TType *ptype1, TType *ptype2 = 0, TType *ptype3 = 0)
     {
         TFunction *function = new TFunction(NewPoolTString(name), *rvalue);
 
@@ -299,12 +299,6 @@ public:
             function->addParameter(param3);
         }
 
-        if(ptype4)
-        {
-            TParameter param4 = {NULL, ptype4};
-            function->addParameter(param4);
-        }
-
         return insert(*function);
     }
 

src/compiler/translator/TranslatorGLSL.cpp

@@ -31,9 +31,6 @@ void TranslatorGLSL::translate(TIntermNode* root) {
     // Write GLSL version.
     writeVersion(getShaderType(), root, sink);
 
-    // Write extension behaviour as needed
-    writeExtensionBehavior();
-
     // Write emulated built-in functions if needed.
     getBuiltInFunctionEmulator().OutputEmulatedFunctionDefinition(
         sink, false);
@@ -45,20 +42,3 @@ void TranslatorGLSL::translate(TIntermNode* root) {
     TOutputGLSL outputGLSL(sink, getArrayIndexClampingStrategy(), getHashFunction(), getNameMap(), getSymbolTable());
     root->traverse(&outputGLSL);
 }
-
-void TranslatorGLSL::writeExtensionBehavior() {
-    TInfoSinkBase& sink = getInfoSink().obj;
-    const TExtensionBehavior& extensionBehavior = getExtensionBehavior();
-    for (TExtensionBehavior::const_iterator iter = extensionBehavior.begin();
-         iter != extensionBehavior.end(); ++iter) {
-        if (iter->second == EBhUndefined)
-            continue;
-
-        // For GLSL output, we don't need to emit most extensions explicitly,
-        // but some we need to translate.
-        if (iter->first == "GL_EXT_shader_texture_lod") {
-            sink << "#extension GL_ARB_shader_texture_lod : "
-                 << getBehaviorString(iter->second) << "\n";
-        }
-    }
-}

src/compiler/translator/TranslatorGLSL.h

@@ -15,9 +15,6 @@ public:
 
 protected:
     virtual void translate(TIntermNode* root);
-
-private:
-    void writeExtensionBehavior();
 };
 
 #endif  // COMPILER_TRANSLATORGLSL_H_

src/libGLESv2/Context.cpp

@@ -2568,7 +2568,6 @@ void Context::initExtensionString()
 
     extensionString += "GL_EXT_read_format_bgra ";
     extensionString += "GL_EXT_robustness ";
-    extensionString += "GL_EXT_shader_texture_lod ";
 
     if (supportsDXT1Textures())
     {

src/libGLESv2/Shader.cpp

@@ -245,7 +245,6 @@ void Shader::initializeCompiler()
             resources.MaxDrawBuffers = mRenderer->getMaxRenderTargets();
             resources.OES_standard_derivatives = mRenderer->getDerivativeInstructionSupport();
             resources.EXT_draw_buffers = mRenderer->getMaxRenderTargets() > 1;
-            resources.EXT_shader_texture_lod = 1;
             // resources.OES_EGL_image_external = mRenderer->getShareHandleSupport() ? 1 : 0; // TODO: commented out until the extension is actually supported.
             resources.FragmentPrecisionHigh = 1;   // Shader Model 2+ always supports FP24 (s16e7) which corresponds to highp
             resources.EXT_frag_depth = 1; // Shader Model 2+ always supports explicit depth output