michael@0: /*
michael@0:  * Copyright 2012 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 GrBackendEffectFactory_DEFINED
michael@0: #define GrBackendEffectFactory_DEFINED
michael@0: 
michael@0: #include "GrTypes.h"
michael@0: #include "SkTemplates.h"
michael@0: #include "SkThread.h"
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: /** Given a GrEffect of a particular type, creates the corresponding graphics-backend-specific
michael@0:     effect object. Also tracks equivalence of shaders generated via a key. Each factory instance
michael@0:     is assigned a generation ID at construction. The ID of the return of GrEffect::getFactory()
michael@0:     is used as a type identifier. Thus a GrEffect subclass must return a singleton from
michael@0:     getFactory(). GrEffect subclasses should use the derived class GrTBackendEffectFactory that is
michael@0:     templated on the GrEffect subclass as their factory object. It requires that the GrEffect
michael@0:     subclass has a nested class (or typedef) GLEffect which is its GL implementation and a subclass
michael@0:     of GrGLEffect.
michael@0:  */
michael@0: 
michael@0: class GrEffectRef;
michael@0: class GrGLEffect;
michael@0: class GrGLCaps;
michael@0: class GrDrawEffect;
michael@0: 
michael@0: class GrBackendEffectFactory : public SkNoncopyable {
michael@0: public:
michael@0:     typedef uint32_t EffectKey;
michael@0:     enum {
michael@0:         kNoEffectKey = 0,
michael@0:         kEffectKeyBits = 10,
michael@0:         /**
michael@0:          * The framework automatically includes coord transforms and texture accesses in their
michael@0:          * effect's EffectKey, so effects don't need to account for them in GenKey().
michael@0:          */
michael@0:         kTextureKeyBits = 4,
michael@0:         kTransformKeyBits = 6,
michael@0:         kAttribKeyBits = 6,
michael@0:         kClassIDBits = 6
michael@0:     };
michael@0: 
michael@0:     virtual EffectKey glEffectKey(const GrDrawEffect&, const GrGLCaps&) const = 0;
michael@0:     virtual GrGLEffect* createGLInstance(const GrDrawEffect&) const = 0;
michael@0: 
michael@0:     bool operator ==(const GrBackendEffectFactory& b) const {
michael@0:         return fEffectClassID == b.fEffectClassID;
michael@0:     }
michael@0:     bool operator !=(const GrBackendEffectFactory& b) const {
michael@0:         return !(*this == b);
michael@0:     }
michael@0: 
michael@0:     virtual const char* name() const = 0;
michael@0: 
michael@0:     static EffectKey GetTransformKey(EffectKey key) {
michael@0:         return key >> (kEffectKeyBits + kTextureKeyBits) & ((1U << kTransformKeyBits) - 1);
michael@0:     }
michael@0: 
michael@0: protected:
michael@0:     enum {
michael@0:         kIllegalEffectClassID = 0,
michael@0:     };
michael@0: 
michael@0:     GrBackendEffectFactory() {
michael@0:         fEffectClassID = kIllegalEffectClassID;
michael@0:     }
michael@0:     virtual ~GrBackendEffectFactory() {}
michael@0: 
michael@0:     static EffectKey GenID() {
michael@0:         SkDEBUGCODE(static const int32_t kClassIDBits = 8 * sizeof(EffectKey) -
michael@0:                            kTextureKeyBits - kEffectKeyBits - kAttribKeyBits);
michael@0:         // fCurrEffectClassID has been initialized to kIllegalEffectClassID. The
michael@0:         // atomic inc returns the old value not the incremented value. So we add
michael@0:         // 1 to the returned value.
michael@0:         int32_t id = sk_atomic_inc(&fCurrEffectClassID) + 1;
michael@0:         SkASSERT(id < (1 << kClassIDBits));
michael@0:         return static_cast<EffectKey>(id);
michael@0:     }
michael@0: 
michael@0:     EffectKey fEffectClassID;
michael@0: 
michael@0: private:
michael@0:     static int32_t fCurrEffectClassID;
michael@0: };
michael@0: 
michael@0: #endif