Implement stroking a path with nv_path_rendering

src/gpu/gl/GrGLPath.cpp

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLPath.h"
 #include "GrGpuGL.h"
+#include "SkStrokeRec.h"
 
 #define GPUGL static_cast<GrGpuGL*>(this->getGpu())
 
 #define GL_CALL(X) GR_GL_CALL(GPUGL->glInterface(), X)
 #define GL_CALL_RET(R, X) GR_GL_CALL_RET(GPUGL->glInterface(), R, X)
 
 namespace {
-inline GrGLubyte verb_to_gl_path_cmd(const SkPath::Verb verb) {
+inline GrGLubyte verb_to_gl_path_cmd(SkPath::Verb verb) {
     static const GrGLubyte gTable[] = {
         GR_GL_MOVE_TO,
         GR_GL_LINE_TO,
         GR_GL_QUADRATIC_CURVE_TO,
         0xFF, // conic
         GR_GL_CUBIC_CURVE_TO,
         GR_GL_CLOSE_PATH,
     };
     GR_STATIC_ASSERT(0 == SkPath::kMove_Verb);
     GR_STATIC_ASSERT(1 == SkPath::kLine_Verb);
     GR_STATIC_ASSERT(2 == SkPath::kQuad_Verb);
     GR_STATIC_ASSERT(4 == SkPath::kCubic_Verb);
     GR_STATIC_ASSERT(5 == SkPath::kClose_Verb);
 
     SkASSERT(verb >= 0 && (size_t)verb < GR_ARRAY_COUNT(gTable));
     return gTable[verb];
 }
 
 #ifdef SK_DEBUG
-inline int num_pts(const SkPath::Verb verb) {
+inline int num_pts(SkPath::Verb verb) {
     static const int gTable[] = {
         1, // move
         1, // line
         2, // quad
         2, // conic
         3, // cubic
         0, // close
     };
     GR_STATIC_ASSERT(0 == SkPath::kMove_Verb);
     GR_STATIC_ASSERT(1 == SkPath::kLine_Verb);
     GR_STATIC_ASSERT(2 == SkPath::kQuad_Verb);
     GR_STATIC_ASSERT(4 == SkPath::kCubic_Verb);
     GR_STATIC_ASSERT(5 == SkPath::kClose_Verb);
 
     SkASSERT(verb >= 0 && (size_t)verb < GR_ARRAY_COUNT(gTable));
     return gTable[verb];
 }
 #endif
+
+inline GrGLenum join_to_gl_join(SkPaint::Join join) {
+    static GrGLenum gSkJoinsToGrGLJoins[] = {
+        GR_GL_MITER_REVERT,
+        GR_GL_ROUND,
+        GR_GL_BEVEL
+    };
+    return gSkJoinsToGrGLJoins[join];
+    GR_STATIC_ASSERT(0 == SkPaint::kMiter_Join);
+    GR_STATIC_ASSERT(1 == SkPaint::kRound_Join);
+    GR_STATIC_ASSERT(2 == SkPaint::kBevel_Join);
+    GR_STATIC_ASSERT(GR_ARRAY_COUNT(gSkJoinsToGrGLJoins) == SkPaint::kJoinCount);
+}
+
+inline GrGLenum cap_to_gl_cap(SkPaint::Cap cap) {
+    static GrGLenum gSkCapsToGrGLCaps[] = {
+        GR_GL_FLAT,
+        GR_GL_ROUND,
+        GR_GL_SQUARE
+    };
+    return gSkCapsToGrGLCaps[cap];
+    GR_STATIC_ASSERT(0 == SkPaint::kButt_Cap);
+    GR_STATIC_ASSERT(1 == SkPaint::kRound_Cap);
+    GR_STATIC_ASSERT(2 == SkPaint::kSquare_Cap);
+    GR_STATIC_ASSERT(GR_ARRAY_COUNT(gSkCapsToGrGLCaps) == SkPaint::kCapCount);
+}
+
 }
 
 static const bool kIsWrapped = false; // The constructor creates the GL path object.
 
-GrGLPath::GrGLPath(GrGpuGL* gpu, const SkPath& path) : INHERITED(gpu, kIsWrapped) {
+GrGLPath::GrGLPath(GrGpuGL* gpu, const SkPath& path, const SkStrokeRec& stroke)
+    : INHERITED(gpu, kIsWrapped, stroke) {
 #ifndef SK_SCALAR_IS_FLOAT
     GrCrash("Assumes scalar is float.");
 #endif
     SkASSERT(!path.isEmpty());
 
     GL_CALL_RET(fPathID, GenPaths(1));
 
     SkSTArray<16, GrGLubyte, true> pathCommands;
     SkSTArray<16, SkPoint, true> pathPoints;
 
@@ skipping 11 matching lines @@
         SkPath::Verb v = static_cast<SkPath::Verb>(pathCommands[i]);
         pathCommands[i] = verb_to_gl_path_cmd(v);
         SkDEBUGCODE(numPts += num_pts(v));
     }
     SkASSERT(pathPoints.count() == numPts);
 
     GL_CALL(PathCommands(fPathID,
                          verbCnt, &pathCommands[0],
                          2 * pointCnt, GR_GL_FLOAT, &pathPoints[0]));
     fBounds = path.getBounds();
+
+    if (stroke.needToApply()) {
+        GL_CALL(PathParameterf(fPathID, GR_GL_PATH_STROKE_WIDTH, SkScalarToFloat(stroke.getWidth())));
+        GL_CALL(PathParameterf(fPathID, GR_GL_PATH_MITER_LIMIT, SkScalarToFloat(stroke.getMiter())));
+        GrGLenum join = join_to_gl_join(stroke.getJoin());
+        GL_CALL(PathParameteri(fPathID, GR_GL_PATH_JOIN_STYLE, join));
+        GrGLenum cap = cap_to_gl_cap(stroke.getCap());
+        GL_CALL(PathParameteri(fPathID, GR_GL_PATH_INITIAL_END_CAP, cap));
+        GL_CALL(PathParameteri(fPathID, GR_GL_PATH_TERMINAL_END_CAP, cap));
+
+        // FIXME: try to account for stroking, without rasterizing the stroke.
+        fBounds.outset(SkScalarToFloat(stroke.getWidth()), SkScalarToFloat(stroke.getWidth()));
+    }
 }
 
 GrGLPath::~GrGLPath() {
     this->release();
 }
 
 void GrGLPath::onRelease() {
     if (0 != fPathID && !this->isWrapped()) {
         GL_CALL(DeletePaths(fPathID, 1));
         fPathID = 0;
     }
 
     INHERITED::onRelease();
 }
 
 void GrGLPath::onAbandon() {
     fPathID = 0;
 
     INHERITED::onAbandon();
 }