Added documentation of stage/TU allocation
http://codereview.appspot.com/6199058/
git-svn-id: http://skia.googlecode.com/svn/trunk@3888 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrTextContext.h b/include/gpu/GrTextContext.h
index 588ae6e..ab1a344 100644
--- a/include/gpu/GrTextContext.h
+++ b/include/gpu/GrTextContext.h
@@ -22,6 +22,11 @@
class SkGpuDevice;
class SkPaint;
+/**
+ * Derived classes can use stages GrPaint::kTotalStages through
+ * GrDrawState::kNumStages-1. The stages before GrPaint::kTotalStages
+ * are reserved for setting up the draw (i.e., textures and filter masks).
+ */
class GrTextContext: public GrRefCnt {
protected:
GrContext* fContext;
diff --git a/src/gpu/GrDrawState.h b/src/gpu/GrDrawState.h
index 386aebd..357f864 100644
--- a/src/gpu/GrDrawState.h
+++ b/src/gpu/GrDrawState.h
@@ -36,6 +36,11 @@
* the last enabled stage. The presence or absence of texture coordinates
* for each stage in the vertex layout indicates whether a stage is enabled
* or not.
+ *
+ * Stages 0 through GrPaint::kTotalStages-1 are reserved for setting up
+ * the draw (i.e., textures and filter masks). Stages GrPaint::kTotalStages
+ * through kNumStages-1 are earmarked for use by GrTextContext and
+ * GrPathRenderer-derived classes.
*/
enum {
kNumStages = 4,
diff --git a/src/gpu/GrPathRenderer.h b/src/gpu/GrPathRenderer.h
index 6a6cea6..ff9fdbb 100644
--- a/src/gpu/GrPathRenderer.h
+++ b/src/gpu/GrPathRenderer.h
@@ -21,6 +21,10 @@
/**
* Base class for drawing paths into a GrDrawTarget.
+ *
+ * Derived classes can use stages GrPaint::kTotalStages through
+ * GrDrawState::kNumStages-1. The stages before GrPaint::kTotalStages
+ * are reserved for setting up the draw (i.e., textures and filter masks).
*/
class GR_API GrPathRenderer : public GrRefCnt {
public: