first cut at HQ GPU scaling; refactored existing bicubic scaler

src/gpu/effects/GrHQScaleTextureEffect.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-#ifndef GrSimpleTextureEffect_DEFINED
-#define GrSimpleTextureEffect_DEFINED
+#ifndef GrHQScaleTextureEffect_DEFINED

[bsalomon, 2013/09/03 20:55:17]

Is this file and the cpp actually used? It looks like you're using the bicubic
effect.

[humper, 2013/09/03 21:45:53]

Nope, this was an unintentional addition.

+#define GrHQScaleTextureEffect_DEFINED
 
 #include "GrSingleTextureEffect.h"
 
-class GrGLSimpleTextureEffect;
+class GrGLHQScaleTextureEffect;
 
 /**
- * The output color of this effect is a modulation of the input color and a sample from a texture.
+ * The output color of this effect is a modulation of the input color and the filtered average of
+ * several samples from a texture.  It is based on Justin Novosad's GPU texture filtering code
+ * from GPU Gems 2.
+ *
  * It allows explicit specification of the filtering and wrap modes (GrTextureParams). It can use
  * local coords, positions, or a custom vertex attribute as input texture coords. The input coords
  * can have a matrix applied in the VS in both the local and position cases but not with a custom
  * attribute coords at this time. It will add a varying to input interpolate texture coords to the
  * FS.
  */
-class GrSimpleTextureEffect : public GrSingleTextureEffect {
+class GrHQScaleTextureEffect : public GrSingleTextureEffect {
 public:
     /* unfiltered, clamp mode */
     static GrEffectRef* Create(GrTexture* tex,
                                const SkMatrix& matrix,
                                CoordsType coordsType = kLocal_CoordsType) {
         SkASSERT(kLocal_CoordsType == coordsType || kPosition_CoordsType == coordsType);
-        AutoEffectUnref effect(SkNEW_ARGS(GrSimpleTextureEffect, (tex, matrix, GrTextureParams::kNone_FilterMode, coordsType)));
+        AutoEffectUnref effect(SkNEW_ARGS(GrHQScaleTextureEffect, (tex, matrix, GrTextureParams::kNone_FilterMode, coordsType)));
         return CreateEffectRef(effect);
     }
 
     /* clamp mode */
     static GrEffectRef* Create(GrTexture* tex,
                                const SkMatrix& matrix,
                                GrTextureParams::FilterMode filterMode,
                                CoordsType coordsType = kLocal_CoordsType) {
         SkASSERT(kLocal_CoordsType == coordsType || kPosition_CoordsType == coordsType);
         AutoEffectUnref effect(
-            SkNEW_ARGS(GrSimpleTextureEffect, (tex, matrix, filterMode, coordsType)));
+            SkNEW_ARGS(GrHQScaleTextureEffect, (tex, matrix, filterMode, coordsType)));
         return CreateEffectRef(effect);
     }
 
     static GrEffectRef* Create(GrTexture* tex,
                                const SkMatrix& matrix,
                                const GrTextureParams& p,
                                CoordsType coordsType = kLocal_CoordsType) {
         SkASSERT(kLocal_CoordsType == coordsType || kPosition_CoordsType == coordsType);
-        AutoEffectUnref effect(SkNEW_ARGS(GrSimpleTextureEffect, (tex, matrix, p, coordsType)));
+        AutoEffectUnref effect(SkNEW_ARGS(GrHQScaleTextureEffect, (tex, matrix, p, coordsType)));
         return CreateEffectRef(effect);
     }
 
     /** Variant that requires the client to install a custom kVec2 vertex attribute that will be
         the source of the coords. No matrix is allowed in this mode. */
     static GrEffectRef* CreateWithCustomCoords(GrTexture* tex, const GrTextureParams& p) {
-        AutoEffectUnref effect(SkNEW_ARGS(GrSimpleTextureEffect, (tex,
+        AutoEffectUnref effect(SkNEW_ARGS(GrHQScaleTextureEffect, (tex,
                                                                   SkMatrix::I(),
                                                                   p,
                                                                   kCustom_CoordsType)));
         return CreateEffectRef(effect);
     }
 
-    virtual ~GrSimpleTextureEffect() {}
+    virtual ~GrHQScaleTextureEffect() {}
 
-    static const char* Name() { return "Texture"; }
+    static const char* Name() { return "ScaledTexture"; }
 
     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
 
-    typedef GrGLSimpleTextureEffect GLEffect;
+    typedef GrGLHQScaleTextureEffect GLEffect;
 
     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
 
 private:
-    GrSimpleTextureEffect(GrTexture* texture,
+    GrHQScaleTextureEffect(GrTexture* texture,
                           const SkMatrix& matrix,
                           GrTextureParams::FilterMode filterMode,
                           CoordsType coordsType)
         : GrSingleTextureEffect(texture, matrix, filterMode, coordsType) {
         SkASSERT(kLocal_CoordsType == coordsType || kPosition_CoordsType == coordsType);
     }
 
-    GrSimpleTextureEffect(GrTexture* texture,
+    GrHQScaleTextureEffect(GrTexture* texture,
                           const SkMatrix& matrix,
                           const GrTextureParams& params,
                           CoordsType coordsType)
         : GrSingleTextureEffect(texture, matrix, params, coordsType) {
         if (kCustom_CoordsType == coordsType) {
             SkASSERT(matrix.isIdentity());
             this->addVertexAttrib(kVec2f_GrSLType);
         }
     }
 
     virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
-        const GrSimpleTextureEffect& ste = CastEffect<GrSimpleTextureEffect>(other);
+        const GrHQScaleTextureEffect& ste = CastEffect<GrHQScaleTextureEffect>(other);
         return this->hasSameTextureParamsMatrixAndCoordsType(ste);
     }
 
     GR_DECLARE_EFFECT_TEST;
 
     typedef GrSingleTextureEffect INHERITED;
 };
 
 #endif