Separate GL path rendering state from GrGpuGL to GrGLPathRendering

Separate GL path rendering state from GrGpuGL to GrGLPathRendering. This
makes GrGpuGL code simpler.

The intention is that while GrGpuGL represents the global environment for GL,
the GrGLPathRendering represents the global environment for path rendering
extension.

Add GrPathRendering, a base class for path rendering, and inherit
GrGLPathRendering from that. Move the path rendering virtual functions from
GrGpu to GrPathRendering.

R=bsalomon@google.com, cdalton@nvidia.com

Author: kkinnunen@nvidia.com

Review URL: https://codereview.chromium.org/452823002

1 files changed, 75 insertions, 0 deletions

diff --git a/src/gpu/GrPathRendering.h b/src/gpu/GrPathRendering.h
new file mode 100644
index 0000000000..863da270c7
--- /dev/null
+++ b/src/gpu/GrPathRendering.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrPathRendering_DEFINED
+#define GrPathRendering_DEFINED
+
+#include "SkPath.h"
+
+class SkStrokeRec;
+class GrPath;
+class GrPathRange;
+class GrGpu;
+
+/**
+ * Abstract class wrapping HW path rendering API.
+ *
+ * The subclasses of this class use the possible HW API to render paths (as opposed to path
+ * rendering implemented in Skia on top of a "3d" HW API).
+ * The subclasses hold the global state needed to render paths, including shadow of the global HW
+ * API state. Similar to GrGpu.
+ *
+ * It is expected that the lifetimes of GrGpuXX and GrXXPathRendering are the same. The call context
+ * interface (eg.  * the concrete instance of GrGpu subclass) should be provided to the instance
+ * during construction.
+ */
+class GrPathRendering {
+public:
+    virtual ~GrPathRendering() { }
+
+    enum PathTransformType {
+        kNone_PathTransformType,        //!< []
+        kTranslateX_PathTransformType,  //!< [kMTransX]
+        kTranslateY_PathTransformType,  //!< [kMTransY]
+        kTranslate_PathTransformType,   //!< [kMTransX, kMTransY]
+        kAffine_PathTransformType,      //!< [kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY]
+
+        kLast_PathTransformType = kAffine_PathTransformType
+    };
+
+    static inline int PathTransformSize(PathTransformType type) {
+        switch (type) {
+            case kNone_PathTransformType:
+                return 0;
+            case kTranslateX_PathTransformType:
+            case kTranslateY_PathTransformType:
+                return 1;
+            case kTranslate_PathTransformType:
+                return 2;
+            case kAffine_PathTransformType:
+                return 6;
+
+            default:
+                SkFAIL("Unknown path transform type");
+                return 0;
+        }
+    }
+
+    virtual GrPath* createPath(const SkPath&, const SkStrokeRec&) = 0;
+    virtual GrPathRange* createPathRange(size_t size, const SkStrokeRec&) = 0;
+    virtual void stencilPath(const GrPath*, SkPath::FillType) = 0;
+    virtual void drawPath(const GrPath*, SkPath::FillType) = 0;
+    virtual void drawPaths(const GrPathRange*, const uint32_t indices[], int count,
+                           const float transforms[], PathTransformType, SkPath::FillType) = 0;
+protected:
+    GrPathRendering() { }
+
+private:
+    GrPathRendering& operator=(const GrPathRendering&);
+};
+
+#endif