michael@0: /*
michael@0:  * Copyright 2011 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef GrGLShaderVar_DEFINED
michael@0: #define GrGLShaderVar_DEFINED
michael@0: 
michael@0: #include "GrGLContext.h"
michael@0: #include "GrGLSL.h"
michael@0: #include "SkString.h"
michael@0: 
michael@0: #define USE_UNIFORM_FLOAT_ARRAYS true
michael@0: 
michael@0: /**
michael@0:  * Represents a variable in a shader
michael@0:  */
michael@0: class GrGLShaderVar {
michael@0: public:
michael@0: 
michael@0:     /**
michael@0:      * Early versions of GLSL have Varying and Attribute; those are later
michael@0:      * deprecated, but we still need to know whether a Varying variable
michael@0:      * should be treated as In or Out.
michael@0:      */
michael@0:     enum TypeModifier {
michael@0:         kNone_TypeModifier,
michael@0:         kOut_TypeModifier,
michael@0:         kIn_TypeModifier,
michael@0:         kInOut_TypeModifier,
michael@0:         kUniform_TypeModifier,
michael@0:         kAttribute_TypeModifier,
michael@0:         kVaryingIn_TypeModifier,
michael@0:         kVaryingOut_TypeModifier
michael@0:     };
michael@0: 
michael@0:     enum Precision {
michael@0:         kLow_Precision,         // lowp
michael@0:         kMedium_Precision,      // mediump
michael@0:         kHigh_Precision,        // highp
michael@0:         kDefault_Precision,     // Default for the current context. We make
michael@0:                                 // fragment shaders default to mediump on ES2
michael@0:                                 // because highp support is not guaranteed (and
michael@0:                                 // we haven't been motivated to test for it).
michael@0:                                 // Otherwise, highp.
michael@0:     };
michael@0: 
michael@0:     /**
michael@0:      * See GL_ARB_fragment_coord_conventions.
michael@0:      */
michael@0:     enum Origin {
michael@0:         kDefault_Origin,        // when set to kDefault the origin field is ignored.
michael@0:         kUpperLeft_Origin,      // only used to declare vec4 in gl_FragCoord.
michael@0:     };
michael@0: 
michael@0:     /**
michael@0:      * Defaults to a float with no precision specifier
michael@0:      */
michael@0:     GrGLShaderVar() {
michael@0:         fType = kFloat_GrSLType;
michael@0:         fTypeModifier = kNone_TypeModifier;
michael@0:         fCount = kNonArray;
michael@0:         fPrecision = kDefault_Precision;
michael@0:         fOrigin = kDefault_Origin;
michael@0:         fUseUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS;
michael@0:     }
michael@0: 
michael@0:     GrGLShaderVar(const char* name, GrSLType type, int arrayCount = kNonArray,
michael@0:                   Precision precision = kDefault_Precision) {
michael@0:         SkASSERT(kVoid_GrSLType != type);
michael@0:         fType = type;
michael@0:         fTypeModifier = kNone_TypeModifier;
michael@0:         fCount = arrayCount;
michael@0:         fPrecision = precision;
michael@0:         fOrigin = kDefault_Origin;
michael@0:         fUseUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS;
michael@0:         fName = name;
michael@0:     }
michael@0: 
michael@0:     GrGLShaderVar(const GrGLShaderVar& var)
michael@0:         : fType(var.fType)
michael@0:         , fTypeModifier(var.fTypeModifier)
michael@0:         , fName(var.fName)
michael@0:         , fCount(var.fCount)
michael@0:         , fPrecision(var.fPrecision)
michael@0:         , fOrigin(var.fOrigin)
michael@0:         , fUseUniformFloatArrays(var.fUseUniformFloatArrays) {
michael@0:         SkASSERT(kVoid_GrSLType != var.fType);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Values for array count that have special meaning. We allow 1-sized arrays.
michael@0:      */
michael@0:     enum {
michael@0:         kNonArray     =  0, // not an array
michael@0:         kUnsizedArray = -1, // an unsized array (declared with [])
michael@0:     };
michael@0: 
michael@0:     /**
michael@0:      * Sets as a non-array.
michael@0:      */
michael@0:     void set(GrSLType type,
michael@0:              TypeModifier typeModifier,
michael@0:              const SkString& name,
michael@0:              Precision precision = kDefault_Precision,
michael@0:              Origin origin = kDefault_Origin,
michael@0:              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
michael@0:         SkASSERT(kVoid_GrSLType != type);
michael@0:         fType = type;
michael@0:         fTypeModifier = typeModifier;
michael@0:         fName = name;
michael@0:         fCount = kNonArray;
michael@0:         fPrecision = precision;
michael@0:         fOrigin = origin;
michael@0:         fUseUniformFloatArrays = useUniformFloatArrays;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Sets as a non-array.
michael@0:      */
michael@0:     void set(GrSLType type,
michael@0:              TypeModifier typeModifier,
michael@0:              const char* name,
michael@0:              Precision precision = kDefault_Precision,
michael@0:              Origin origin = kDefault_Origin,
michael@0:              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
michael@0:         SkASSERT(kVoid_GrSLType != type);
michael@0:         fType = type;
michael@0:         fTypeModifier = typeModifier;
michael@0:         fName = name;
michael@0:         fCount = kNonArray;
michael@0:         fPrecision = precision;
michael@0:         fOrigin = origin;
michael@0:         fUseUniformFloatArrays = useUniformFloatArrays;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Set all var options
michael@0:      */
michael@0:     void set(GrSLType type,
michael@0:              TypeModifier typeModifier,
michael@0:              const SkString& name,
michael@0:              int count,
michael@0:              Precision precision = kDefault_Precision,
michael@0:              Origin origin = kDefault_Origin,
michael@0:              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
michael@0:         SkASSERT(kVoid_GrSLType != type);
michael@0:         fType = type;
michael@0:         fTypeModifier = typeModifier;
michael@0:         fName = name;
michael@0:         fCount = count;
michael@0:         fPrecision = precision;
michael@0:         fOrigin = origin;
michael@0:         fUseUniformFloatArrays = useUniformFloatArrays;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Set all var options
michael@0:      */
michael@0:     void set(GrSLType type,
michael@0:              TypeModifier typeModifier,
michael@0:              const char* name,
michael@0:              int count,
michael@0:              Precision precision = kDefault_Precision,
michael@0:              Origin origin = kDefault_Origin,
michael@0:              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
michael@0:         SkASSERT(kVoid_GrSLType != type);
michael@0:         fType = type;
michael@0:         fTypeModifier = typeModifier;
michael@0:         fName = name;
michael@0:         fCount = count;
michael@0:         fPrecision = precision;
michael@0:         fOrigin = origin;
michael@0:         fUseUniformFloatArrays = useUniformFloatArrays;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Is the var an array.
michael@0:      */
michael@0:     bool isArray() const { return kNonArray != fCount; }
michael@0:     /**
michael@0:      * Is this an unsized array, (i.e. declared with []).
michael@0:      */
michael@0:     bool isUnsizedArray() const { return kUnsizedArray == fCount; }
michael@0:     /**
michael@0:      * Get the array length of the var.
michael@0:      */
michael@0:     int getArrayCount() const { return fCount; }
michael@0:     /**
michael@0:      * Set the array length of the var
michael@0:      */
michael@0:     void setArrayCount(int count) { fCount = count; }
michael@0:     /**
michael@0:      * Set to be a non-array.
michael@0:      */
michael@0:     void setNonArray() { fCount = kNonArray; }
michael@0:     /**
michael@0:      * Set to be an unsized array.
michael@0:      */
michael@0:     void setUnsizedArray() { fCount = kUnsizedArray; }
michael@0: 
michael@0:     /**
michael@0:      * Access the var name as a writable string
michael@0:      */
michael@0:     SkString* accessName() { return &fName; }
michael@0:     /**
michael@0:      * Set the var name
michael@0:      */
michael@0:     void setName(const SkString& n) { fName = n; }
michael@0:     void setName(const char* n) { fName = n; }
michael@0: 
michael@0:     /**
michael@0:      * Get the var name.
michael@0:      */
michael@0:     const SkString& getName() const { return fName; }
michael@0: 
michael@0:     /**
michael@0:      * Shortcut for this->getName().c_str();
michael@0:      */
michael@0:     const char* c_str() const { return this->getName().c_str(); }
michael@0: 
michael@0:     /**
michael@0:      * Get the type of the var
michael@0:      */
michael@0:     GrSLType getType() const { return fType; }
michael@0:     /**
michael@0:      * Set the type of the var
michael@0:      */
michael@0:     void setType(GrSLType type) { fType = type; }
michael@0: 
michael@0:     TypeModifier getTypeModifier() const { return fTypeModifier; }
michael@0:     void setTypeModifier(TypeModifier type) { fTypeModifier = type; }
michael@0: 
michael@0:     /**
michael@0:      * Get the precision of the var
michael@0:      */
michael@0:     Precision getPrecision() const { return fPrecision; }
michael@0: 
michael@0:     /**
michael@0:      * Set the precision of the var
michael@0:      */
michael@0:     void setPrecision(Precision p) { fPrecision = p; }
michael@0: 
michael@0:     /**
michael@0:      * Get the origin of the var
michael@0:      */
michael@0:     Origin getOrigin() const { return fOrigin; }
michael@0: 
michael@0:     /**
michael@0:      * Set the origin of the var
michael@0:      */
michael@0:     void setOrigin(Origin origin) { fOrigin = origin; }
michael@0: 
michael@0:     /**
michael@0:      * Write a declaration of this variable to out.
michael@0:      */
michael@0:     void appendDecl(const GrGLContextInfo& ctxInfo, SkString* out) const {
michael@0:         if (kUpperLeft_Origin == fOrigin) {
michael@0:             // this is the only place where we specify a layout modifier. If we use other layout
michael@0:             // modifiers in the future then they should be placed in a list.
michael@0:             out->append("layout(origin_upper_left) ");
michael@0:         }
michael@0:         if (this->getTypeModifier() != kNone_TypeModifier) {
michael@0:            out->append(TypeModifierString(this->getTypeModifier(),
michael@0:                                           ctxInfo.glslGeneration()));
michael@0:            out->append(" ");
michael@0:         }
michael@0:         out->append(PrecisionString(fPrecision, ctxInfo.standard()));
michael@0:         GrSLType effectiveType = this->getType();
michael@0:         if (this->isArray()) {
michael@0:             if (this->isUnsizedArray()) {
michael@0:                 out->appendf("%s %s[]",
michael@0:                              GrGLSLTypeString(effectiveType),
michael@0:                              this->getName().c_str());
michael@0:             } else {
michael@0:                 SkASSERT(this->getArrayCount() > 0);
michael@0:                 out->appendf("%s %s[%d]",
michael@0:                              GrGLSLTypeString(effectiveType),
michael@0:                              this->getName().c_str(),
michael@0:                              this->getArrayCount());
michael@0:             }
michael@0:         } else {
michael@0:             out->appendf("%s %s",
michael@0:                          GrGLSLTypeString(effectiveType),
michael@0:                          this->getName().c_str());
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     void appendArrayAccess(int index, SkString* out) const {
michael@0:         out->appendf("%s[%d]%s",
michael@0:                      this->getName().c_str(),
michael@0:                      index,
michael@0:                      fUseUniformFloatArrays ? "" : ".x");
michael@0:     }
michael@0: 
michael@0:     void appendArrayAccess(const char* indexName, SkString* out) const {
michael@0:         out->appendf("%s[%s]%s",
michael@0:                      this->getName().c_str(),
michael@0:                      indexName,
michael@0:                      fUseUniformFloatArrays ? "" : ".x");
michael@0:     }
michael@0: 
michael@0:     static const char* PrecisionString(Precision p, GrGLStandard standard) {
michael@0:         // Desktop GLSL has added precision qualifiers but they don't do anything.
michael@0:         if (kGLES_GrGLStandard == standard) {
michael@0:             switch (p) {
michael@0:                 case kLow_Precision:
michael@0:                     return "lowp ";
michael@0:                 case kMedium_Precision:
michael@0:                     return "mediump ";
michael@0:                 case kHigh_Precision:
michael@0:                     return "highp ";
michael@0:                 case kDefault_Precision:
michael@0:                     return "";
michael@0:                 default:
michael@0:                     GrCrash("Unexpected precision type.");
michael@0:             }
michael@0:         }
michael@0:         return "";
michael@0:     }
michael@0: 
michael@0: private:
michael@0:     static const char* TypeModifierString(TypeModifier t, GrGLSLGeneration gen) {
michael@0:         switch (t) {
michael@0:             case kNone_TypeModifier:
michael@0:                 return "";
michael@0:             case kIn_TypeModifier:
michael@0:                 return "in";
michael@0:             case kInOut_TypeModifier:
michael@0:                 return "inout";
michael@0:             case kOut_TypeModifier:
michael@0:                 return "out";
michael@0:             case kUniform_TypeModifier:
michael@0:                 return "uniform";
michael@0:             case kAttribute_TypeModifier:
michael@0:                 return k110_GrGLSLGeneration == gen ? "attribute" : "in";
michael@0:             case kVaryingIn_TypeModifier:
michael@0:                 return k110_GrGLSLGeneration == gen ? "varying" : "in";
michael@0:             case kVaryingOut_TypeModifier:
michael@0:                 return k110_GrGLSLGeneration == gen ? "varying" : "out";
michael@0:             default:
michael@0:                 GrCrash("Unknown shader variable type modifier.");
michael@0:                 return ""; // suppress warning
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     GrSLType        fType;
michael@0:     TypeModifier    fTypeModifier;
michael@0:     SkString        fName;
michael@0:     int             fCount;
michael@0:     Precision       fPrecision;
michael@0:     Origin          fOrigin;
michael@0:     /// Work around driver bugs on some hardware that don't correctly
michael@0:     /// support uniform float []
michael@0:     bool            fUseUniformFloatArrays;
michael@0: };
michael@0: 
michael@0: #endif