Continue making Ganesh use absolute texture coordinates - take 2

The idea here is that the GrCoordTransform will actually hold a GrTextureProxy (rather than a GrTexture) and then, in GrGLSLPrimitiveProcessor::GetTransformMatrix, use the instantiated width & height (when uploading the transform matrix)

Relanding of: https://skia-review.googlesource.com/c/6977/


Change-Id: Ibc9b9e354f7fc23b1a6e6e4fe7c9fe3cef771c02
Reviewed-on: https://skia-review.googlesource.com/7265
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

2 files changed, 51 insertions, 27 deletions

diff --git a/include/gpu/GrCoordTransform.h b/include/gpu/GrCoordTransform.h
index 1f1cac7505..5c16c89679 100644
--- a/include/gpu/GrCoordTransform.h
+++ b/include/gpu/GrCoordTransform.h
@@ -20,7 +20,11 @@
  */
 class GrCoordTransform : SkNoncopyable {
 public:
-    GrCoordTransform() { SkDEBUGCODE(fInProcessor = false); }
+    GrCoordTransform()
+        : fTexture(nullptr)
+        , fNormalize(false) {
+        SkDEBUGCODE(fInProcessor = false);
+    }
 
     /**
      * Create a transformation that maps [0, 1] to a texture's boundaries. The precision is inferred
@@ -30,7 +34,7 @@ public:
     GrCoordTransform(const GrTexture* texture, GrSamplerParams::FilterMode filter) {
         SkASSERT(texture);
         SkDEBUGCODE(fInProcessor = false);
-        this->reset(texture, filter);
+        this->reset(SkMatrix::I(), texture, filter);
     }
 
     /**
@@ -52,18 +56,23 @@ public:
         this->reset(m, precision);
     }
 
-    void reset(const GrTexture* texture, GrSamplerParams::FilterMode filter) {
+    void reset(const SkMatrix&, const GrTexture*, GrSamplerParams::FilterMode filter,
+               bool normalize = true);
+
+    void reset(const SkMatrix& m, GrSLPrecision precision = kDefault_GrSLPrecision) {
         SkASSERT(!fInProcessor);
-        SkASSERT(texture);
-        this->reset(MakeDivByTextureWHMatrix(texture), texture, filter);
+        fMatrix = m;
+        fTexture = nullptr;
+        fNormalize = false;
+        fReverseY = false;
+        fPrecision = precision;
     }
 
-    void reset(const SkMatrix&, const GrTexture*, GrSamplerParams::FilterMode filter);
-    void reset(const SkMatrix& m, GrSLPrecision precision = kDefault_GrSLPrecision);
-
     GrCoordTransform& operator= (const GrCoordTransform& that) {
         SkASSERT(!fInProcessor);
         fMatrix = that.fMatrix;
+        fTexture = that.fTexture;
+        fNormalize = that.fNormalize;
         fReverseY = that.fReverseY;
         fPrecision = that.fPrecision;
         return *this;
@@ -78,29 +87,38 @@ public:
         return &fMatrix;
     }
 
-    bool operator==(const GrCoordTransform& that) const {
-        return fMatrix.cheapEqualTo(that.fMatrix) &&
-               fReverseY == that.fReverseY &&
-               fPrecision == that.fPrecision;
+    bool hasSameEffectAs(const GrCoordTransform& that) const {
+        if (fNormalize != that.fNormalize ||
+            fReverseY != that.fReverseY ||
+            fPrecision != that.fPrecision ||
+            !fMatrix.cheapEqualTo(that.fMatrix)) {
+            return false;
+        }
+
+        if (fNormalize) {
+            SkASSERT(fTexture && that.fTexture);
+            return fTexture->width() == that.fTexture->width() &&
+                   fTexture->height() == that.fTexture->height();
+        }
+
+        return true;
     }
 
-    bool operator!=(const GrCoordTransform& that) const { return !(*this == that); }
-
     const SkMatrix& getMatrix() const { return fMatrix; }
+    const GrTexture* texture() const { return fTexture; }
+    bool normalize() const { return fNormalize; }
     bool reverseY() const { return fReverseY; }
     GrSLPrecision precision() const { return fPrecision; }
 
-    /** Useful for effects that want to insert a texture matrix that is implied by the texture
-        dimensions */
-    static inline SkMatrix MakeDivByTextureWHMatrix(const GrTexture* texture) {
-        SkASSERT(texture);
-        SkMatrix mat;
-        (void)mat.setIDiv(texture->width(), texture->height());
-        return mat;
-    }
-
 private:
+    // The textures' effect is to optionally normalize the final matrix, so a blind
+    // equality check could be misleading
+    bool operator==(const GrCoordTransform& that) const;
+    bool operator!=(const GrCoordTransform& that) const;
+
     SkMatrix                fMatrix;
+    const GrTexture*        fTexture;
+    bool                    fNormalize;
     bool                    fReverseY;
     GrSLPrecision           fPrecision;
     typedef SkNoncopyable INHERITED;
diff --git a/include/gpu/SkGr.h b/include/gpu/SkGr.h
index e2f09e5ac2..3f72fa134d 100644
--- a/include/gpu/SkGr.h
+++ b/include/gpu/SkGr.h
@@ -77,11 +77,17 @@ static inline GrColor SkPMColorToGrColor(SkPMColor c) {
 
 ////////////////////////////////////////////////////////////////////////////////
 /** Returns a texture representing the bitmap that is compatible with the GrSamplerParams. The
-    texture is inserted into the cache (unless the bitmap is marked volatile) and can be
-    retrieved again via this function. */
-GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&, const GrSamplerParams&);
+ *  texture is inserted into the cache (unless the bitmap is marked volatile) and can be
+ *  retrieved again via this function.
+ *  The 'scaleAdjust' in/out parameter will be updated to hold any rescaling that needs to be
+ *  performed on the absolute texture coordinates (e.g., if the texture is resized out to
+ *  the next power of two). It can be null if the caller is sure the bitmap won't be resized.
+ */
+GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&,
+                                    const GrSamplerParams&, SkScalar scaleAdjust[2]);
 
-sk_sp<GrTexture> GrMakeCachedBitmapTexture(GrContext*, const SkBitmap&, const GrSamplerParams&);
+sk_sp<GrTexture> GrMakeCachedBitmapTexture(GrContext*, const SkBitmap&,
+                                           const GrSamplerParams&, SkScalar scaleAdjust[2]);
 
 // TODO: Move SkImageInfo2GrPixelConfig to SkGrPriv.h (requires cleanup to SkWindow its subclasses).
 GrPixelConfig SkImageInfo2GrPixelConfig(const SkImageInfo& info, const GrCaps& caps);