Revert "Revert "move homogenous with stride to matrixpriv""

This reverts commit de71572f650005e36d4fc2fe95fb5677a25ae4f6.

Revert "Revert "Transform vertices for distance field glyphs on CPU.""

This reverts commit f226e66d75374e370f3ae2c6895bc689670e9e18.

Change-Id: I2545afae3beb1d6b14bba056853ed826ae7a4679
Reviewed-on: https://skia-review.googlesource.com/86603
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

4 files changed, 61 insertions, 58 deletions

diff --git a/src/gpu/text/GrAtlasTextBlob.cpp b/src/gpu/text/GrAtlasTextBlob.cpp
index 0b25a34ed1..02f3ab0a21 100644
--- a/src/gpu/text/GrAtlasTextBlob.cpp
+++ b/src/gpu/text/GrAtlasTextBlob.cpp
@@ -96,7 +96,13 @@ void GrAtlasTextBlob::appendGlyph(int runIndex,
 
     run.fInitialized = true;
 
-    size_t vertexStride = GetVertexStride(format);
+    bool hasW = subRun->hasWCoord();
+    // DF glyphs drawn in perspective must always have a w coord.
+    SkASSERT(hasW || !subRun->drawAsDistanceFields() || !fInitialViewMatrix.hasPerspective());
+    // Non-DF glyphs should never have a w coord.
+    SkASSERT(!hasW || subRun->drawAsDistanceFields());
+
+    size_t vertexStride = GetVertexStride(format, hasW);
 
     subRun->setMaskFormat(format);
 
@@ -105,53 +111,29 @@ void GrAtlasTextBlob::appendGlyph(int runIndex,
 
     intptr_t vertex = reinterpret_cast<intptr_t>(this->fVertices + subRun->vertexEndIndex());
 
-    if (kARGB_GrMaskFormat != glyph->fMaskFormat) {
-        // V0
-        SkPoint* position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fLeft, positions.fTop);
-        SkColor* colorPtr = reinterpret_cast<SkColor*>(vertex + sizeof(SkPoint));
-        *colorPtr = color;
-        vertex += vertexStride;
-
-        // V1
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fLeft, positions.fBottom);
-        colorPtr = reinterpret_cast<SkColor*>(vertex + sizeof(SkPoint));
-        *colorPtr = color;
-        vertex += vertexStride;
-
-        // V2
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fRight, positions.fTop);
-        colorPtr = reinterpret_cast<SkColor*>(vertex + sizeof(SkPoint));
-        *colorPtr = color;
-        vertex += vertexStride;
-
-        // V3
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fRight, positions.fBottom);
-        colorPtr = reinterpret_cast<SkColor*>(vertex + sizeof(SkPoint));
-        *colorPtr = color;
-    } else {
-        // V0
-        SkPoint* position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fLeft, positions.fTop);
-        vertex += vertexStride;
-
-        // V1
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fLeft, positions.fBottom);
-        vertex += vertexStride;
-
-        // V2
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fRight, positions.fTop);
-        vertex += vertexStride;
-
-        // V3
-        position = reinterpret_cast<SkPoint*>(vertex);
-        position->set(positions.fRight, positions.fBottom);
-    }
+    // We always write the third position component used by SDFs. If it is unused it gets
+    // overwritten. Similarly, we always write the color and the blob will later overwrite it
+    // with texture coords if it is unused.
+    size_t colorOffset = hasW ? sizeof(SkPoint3) : sizeof(SkPoint);
+    // V0
+    *reinterpret_cast<SkPoint3*>(vertex) = {positions.fLeft, positions.fTop, 1.f};
+    *reinterpret_cast<GrColor*>(vertex + colorOffset) = color;
+    vertex += vertexStride;
+
+    // V1
+    *reinterpret_cast<SkPoint3*>(vertex) = {positions.fLeft, positions.fBottom, 1.f};
+    *reinterpret_cast<GrColor*>(vertex + colorOffset) = color;
+    vertex += vertexStride;
+
+    // V2
+    *reinterpret_cast<SkPoint3*>(vertex) = {positions.fRight, positions.fTop, 1.f};
+    *reinterpret_cast<GrColor*>(vertex + colorOffset) = color;
+    vertex += vertexStride;
+
+    // V3
+    *reinterpret_cast<SkPoint3*>(vertex) = {positions.fRight, positions.fBottom, 1.f};
+    *reinterpret_cast<GrColor*>(vertex + colorOffset) = color;
+
     subRun->appendVertices(vertexStride);
     fGlyphs[subRun->glyphEndIndex()] = glyph;
     subRun->glyphAppended();
@@ -185,6 +167,7 @@ bool GrAtlasTextBlob::mustRegenerate(const GrTextUtils::Paint& paint,
         return true;
     }
 
+    /** This could be relaxed for blobs with only distance field glyphs. */
     if (fInitialViewMatrix.hasPerspective() && !fInitialViewMatrix.cheapEqualTo(viewMatrix)) {
         return true;
     }
diff --git a/src/gpu/text/GrAtlasTextBlob.h b/src/gpu/text/GrAtlasTextBlob.h
index 450e256d38..282fa98141 100644
--- a/src/gpu/text/GrAtlasTextBlob.h
+++ b/src/gpu/text/GrAtlasTextBlob.h
@@ -17,6 +17,7 @@
 #include "SkMaskFilter.h"
 #include "SkOpts.h"
 #include "SkPathEffect.h"
+#include "SkPoint3.h"
 #include "SkRasterizer.h"
 #include "SkSurfaceProps.h"
 #include "SkTInternalLList.h"
@@ -53,6 +54,12 @@ public:
 
     static sk_sp<GrAtlasTextBlob> Make(GrMemoryPool* pool, int glyphCount, int runCount);
 
+    /**
+     * We currently force regeneration of a blob if old or new matrix differ in having perspective.
+     * If we ever change that then the key must contain the perspectiveness when there are distance
+     * fields as perspective distance field use 3 component vertex positions and non-perspective
+     * uses 2.
+     */
     struct Key {
         Key() {
             sk_bzero(this, sizeof(Key));
@@ -126,12 +133,13 @@ public:
     }
 
     // sets the last subrun of runIndex to use distance field text
-    void setSubRunHasDistanceFields(int runIndex, bool hasLCD, bool isAntiAlias) {
+    void setSubRunHasDistanceFields(int runIndex, bool hasLCD, bool isAntiAlias, bool hasWCoord) {
         Run& run = fRuns[runIndex];
         Run::SubRunInfo& subRun = run.fSubRunInfo.back();
         subRun.setUseLCDText(hasLCD);
         subRun.setAntiAliased(isAntiAlias);
         subRun.setDrawAsDistanceFields();
+        subRun.setHasWCoord(hasWCoord);
     }
 
     void setRunDrawAsPaths(int runIndex) {
@@ -169,13 +177,15 @@ public:
                      SkGlyphCache*, const SkGlyph& skGlyph,
                      SkScalar x, SkScalar y, SkScalar scale, bool treatAsBMP);
 
-    static size_t GetVertexStride(GrMaskFormat maskFormat) {
+    static size_t GetVertexStride(GrMaskFormat maskFormat, bool isDistanceFieldWithWCoord) {
         switch (maskFormat) {
             case kA8_GrMaskFormat:
-                return kGrayTextVASize;
+                return isDistanceFieldWithWCoord ? kGrayTextDFPerspectiveVASize : kGrayTextVASize;
             case kARGB_GrMaskFormat:
+                SkASSERT(!isDistanceFieldWithWCoord);
                 return kColorTextVASize;
             default:
+                SkASSERT(!isDistanceFieldWithWCoord);
                 return kLCDTextVASize;
         }
     }
@@ -232,8 +242,10 @@ public:
     // position + local coord
     static const size_t kColorTextVASize = sizeof(SkPoint) + sizeof(SkIPoint16);
     static const size_t kGrayTextVASize = sizeof(SkPoint) + sizeof(GrColor) + sizeof(SkIPoint16);
+    static const size_t kGrayTextDFPerspectiveVASize =
+            sizeof(SkPoint3) + sizeof(GrColor) + sizeof(SkIPoint16);
     static const size_t kLCDTextVASize = kGrayTextVASize;
-    static const size_t kMaxVASize = kGrayTextVASize;
+    static const size_t kMaxVASize = kGrayTextDFPerspectiveVASize;
     static const int kVerticesPerGlyph = 4;
 
     static void AssertEqual(const GrAtlasTextBlob&, const GrAtlasTextBlob&);
@@ -419,7 +431,7 @@ private:
 
             // This function assumes the translation will be applied before it is called again
             void computeTranslation(const SkMatrix& viewMatrix, SkScalar x, SkScalar y,
-                                    SkScalar*transX, SkScalar* transY);
+                                    SkScalar* transX, SkScalar* transY);
 
             // df properties
             void setDrawAsDistanceFields() { fFlags |= kDrawAsSDF_Flag; }
@@ -432,12 +444,17 @@ private:
                 fFlags = antiAliased ? fFlags | kAntiAliased_Flag : fFlags & ~kAntiAliased_Flag;
             }
             bool isAntiAliased() const { return SkToBool(fFlags & kAntiAliased_Flag); }
+            void setHasWCoord(bool hasW) {
+                fFlags  = hasW ? (fFlags | kHasWCoord_Flag) : fFlags & ~kHasWCoord_Flag;
+            }
+            bool hasWCoord() const { return SkToBool(fFlags & kHasWCoord_Flag); }
 
         private:
             enum Flag {
                 kDrawAsSDF_Flag = 0x1,
                 kUseLCDText_Flag = 0x2,
-                kAntiAliased_Flag = 0x4
+                kAntiAliased_Flag = 0x4,
+                kHasWCoord_Flag = 0x8
             };
 
             GrDrawOpAtlas::BulkUseTokenUpdater fBulkUseToken;
diff --git a/src/gpu/text/GrAtlasTextBlobVertexRegenerator.cpp b/src/gpu/text/GrAtlasTextBlobVertexRegenerator.cpp
index 28b2e0f0c0..1be5ae330c 100644
--- a/src/gpu/text/GrAtlasTextBlobVertexRegenerator.cpp
+++ b/src/gpu/text/GrAtlasTextBlobVertexRegenerator.cpp
@@ -71,8 +71,8 @@ inline void regen_vertices(char* vertex, const GrGlyph* glyph, size_t vertexStri
 
     // This is a bit wonky, but sometimes we have LCD text, in which case we won't have color
     // vertices, hence vertexStride - sizeof(SkIPoint16)
-    intptr_t colorOffset = sizeof(SkPoint);
     intptr_t texCoordOffset = vertexStride - sizeof(SkIPoint16);
+    intptr_t colorOffset = texCoordOffset - sizeof(GrColor);
 
     // V0
     if (regenPos) {
@@ -211,8 +211,9 @@ Regenerator::Result Regenerator::doRegen() {
         }
     }
 
+    bool hasW = fSubRun->hasWCoord();
     Result result;
-    auto vertexStride = GetVertexStride(fSubRun->maskFormat());
+    auto vertexStride = GetVertexStride(fSubRun->maskFormat(), hasW);
     char* currVertex = fBlob->fVertices + fSubRun->vertexStartIndex() +
                        fCurrGlyph * kVerticesPerGlyph * vertexStride;
     result.fFirstVertex = currVertex;
@@ -300,7 +301,8 @@ Regenerator::Result Regenerator::regenerate() {
             return this->doRegen<false, true, true, true>();
         case kNoRegen: {
             Result result;
-            auto vertexStride = GetVertexStride(fSubRun->maskFormat());
+            bool hasW = fSubRun->hasWCoord();
+            auto vertexStride = GetVertexStride(fSubRun->maskFormat(), hasW);
             result.fGlyphsRegenerated = fSubRun->glyphCount() - fCurrGlyph;
             result.fFirstVertex = fBlob->fVertices + fSubRun->vertexStartIndex() +
                                   fCurrGlyph * kVerticesPerGlyph * vertexStride;
diff --git a/src/gpu/text/GrAtlasTextContext.cpp b/src/gpu/text/GrAtlasTextContext.cpp
index d617786944..3faa0f7b87 100644
--- a/src/gpu/text/GrAtlasTextContext.cpp
+++ b/src/gpu/text/GrAtlasTextContext.cpp
@@ -646,13 +646,14 @@ void GrAtlasTextContext::drawDFPosText(GrAtlasTextBlob* blob, int runIndex,
     SkTDArray<char> fallbackTxt;
     SkTDArray<SkScalar> fallbackPos;
 
+    bool hasWCoord = viewMatrix.hasPerspective();
     // Setup distance field paint and text ratio
     SkScalar textRatio;
     SkPaint dfPaint(paint);
     this->initDistanceFieldPaint(blob, &dfPaint, &textRatio, viewMatrix);
     blob->setHasDistanceField();
     blob->setSubRunHasDistanceFields(runIndex, paint.skPaint().isLCDRenderText(),
-                                     paint.skPaint().isAntiAlias());
+                                     paint.skPaint().isAntiAlias(), hasWCoord);
 
     GrAtlasTextStrike* currStrike = nullptr;