read/write m44

Inspired by https://skia-review.googlesource.com/c/skia/+/303271

Change-Id: I64816f8db1742d263c8f668a7b44a08f20d82f5e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/304065
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

include/core/SkM44.h

@@ -111,6 +111,15 @@ struct SkV4 {
 
     const float* ptr() const { return &x; }
     float* ptr() { return &x; }
+
+    float operator[](int i) const {
+        SkASSERT(i >= 0 && i < 4);
+        return this->ptr()[i];
+    }
+    float& operator[](int i) {
+        SkASSERT(i >= 0 && i < 4);
+        return this->ptr()[i];
+    }
 };
 
 /**

src/core/SkReadBuffer.cpp

@@ -165,6 +165,17 @@ void SkReadBuffer::readPoint3(SkPoint3* point) {
     this->readPad32(point, sizeof(SkPoint3));
 }
 
+void SkReadBuffer::read(SkM44* matrix) {
+    if (this->isValid()) {
+        if (const float* m = (const float*)this->skip(sizeof(float) * 16)) {
+            *matrix = SkM44::ColMajor(m);
+        }
+    }
+    if (!this->isValid()) {
+        *matrix = SkM44();
+    }
+}
+
 void SkReadBuffer::readMatrix(SkMatrix* matrix) {
     size_t size = 0;
     if (this->isValid()) {

src/core/SkReadBuffer.h

@@ -92,6 +92,7 @@ public:
     void readPoint(SkPoint* point);
     SkPoint readPoint() { SkPoint p; this->readPoint(&p); return p; }
     void readPoint3(SkPoint3* point);
+    void read(SkM44*);
     void readMatrix(SkMatrix* matrix);
     void readIRect(SkIRect* rect);
     void readRect(SkRect* rect);

src/core/SkWriteBuffer.cpp

@@ -9,10 +9,12 @@
 
 #include "include/core/SkBitmap.h"
 #include "include/core/SkData.h"
+#include "include/core/SkM44.h"
 #include "include/core/SkStream.h"
 #include "include/core/SkTypeface.h"
 #include "include/private/SkTo.h"
 #include "src/core/SkImagePriv.h"
+#include "src/core/SkMatrixPriv.h"
 #include "src/core/SkPaintPriv.h"
 #include "src/core/SkPtrRecorder.h"
 
@@ -102,6 +104,10 @@ void SkBinaryWriteBuffer::writePointArray(const SkPoint* point, uint32_t count)
     fWriter.write(point, count * sizeof(SkPoint));
 }
 
+void SkBinaryWriteBuffer::write(const SkM44& matrix) {
+    fWriter.write(SkMatrixPriv::M44ColMajor(matrix), sizeof(float) * 16);
+}
+
 void SkBinaryWriteBuffer::writeMatrix(const SkMatrix& matrix) {
     fWriter.writeMatrix(matrix);
 }

src/core/SkWriteBuffer.h

@@ -16,6 +16,7 @@
 
 class SkFactorySet;
 class SkImage;
+class SkM44;
 class SkPath;
 class SkRefCntSet;
 
@@ -54,6 +55,7 @@ public:
     virtual void writePoint(const SkPoint& point) = 0;
     virtual void writePointArray(const SkPoint* point, uint32_t count) = 0;
     virtual void writePoint3(const SkPoint3& point) = 0;
+    virtual void write(const SkM44&) = 0;
     virtual void writeMatrix(const SkMatrix& matrix) = 0;
     virtual void writeIRect(const SkIRect& rect) = 0;
     virtual void writeRect(const SkRect& rect) = 0;
@@ -115,6 +117,7 @@ public:
     void writePoint(const SkPoint& point) override;
     void writePointArray(const SkPoint* point, uint32_t count) override;
     void writePoint3(const SkPoint3& point) override;
+    void write(const SkM44&) override;
     void writeMatrix(const SkMatrix& matrix) override;
     void writeIRect(const SkIRect& rect) override;
     void writeRect(const SkRect& rect) override;

tools/debugger/JsonWriteBuffer.cpp

@@ -139,6 +139,20 @@ void JsonWriteBuffer::writePointArray(const SkPoint* point, uint32_t count) {
     fWriter->endArray();
 }
 
+void JsonWriteBuffer::write(const SkM44& matrix) {
+    this->append("matrix");
+    fWriter->beginArray();
+    for (int r = 0; r < 4; ++r) {
+        fWriter->beginArray(nullptr, false);
+        SkV4 v = matrix.row(r);
+        for (int c = 0; c < 4; ++c) {
+            fWriter->appendFloat(v[c]);
+        }
+        fWriter->endArray();
+    }
+    fWriter->endArray();
+}
+
 void JsonWriteBuffer::writeMatrix(const SkMatrix& matrix) {
     this->append("matrix");
     DrawCommand::MakeJsonMatrix(*fWriter, matrix);

tools/debugger/JsonWriteBuffer.h

@@ -37,6 +37,7 @@ public:
     void   writePoint(const SkPoint& point) override;
     void   writePointArray(const SkPoint* point, uint32_t count) override;
     void   writePoint3(const SkPoint3& point) override;
+    void   write(const SkM44&) override;
     void   writeMatrix(const SkMatrix& matrix) override;
     void   writeIRect(const SkIRect& rect) override;
     void   writeRect(const SkRect& rect) override;