Re-adding analytical GeoProc for rectangles

src/gpu/batches/GrAnalyticRectBatch.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrAnalyticRectBatch.h"
+
+#include "GrBatchFlushState.h"
+#include "GrBatchTest.h"
+#include "GrGeometryProcessor.h"
+#include "GrInvariantOutput.h"
+#include "GrProcessor.h"
+#include "GrResourceProvider.h"
+#include "SkRRect.h"
+#include "SkStrokeRec.h"
+#include "batches/GrVertexBatch.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
+#include "glsl/GrGLSLGeometryProcessor.h"
+#include "glsl/GrGLSLProgramDataManager.h"
+#include "glsl/GrGLSLVarying.h"
+#include "glsl/GrGLSLVertexShaderBuilder.h"
+#include "glsl/GrGLSLUniformHandler.h"
+#include "glsl/GrGLSLUtil.h"
+
+namespace {
+
+struct RectVertex {
+    SkPoint  fPos;
+    GrColor  fColor;
+    SkPoint  fCenter;
+    SkVector fDownDir;
+    SkScalar fHalfWidth;
+    SkScalar fHalfHeight;
+};
+
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/**
+ * The output of this effect is the input color and coverage for an arbitrarily oriented rect. The
+ * rect is specified as:
+ *      Center of the rect
+ *      Unit vector point down the height of the rect
+ *      Half width + 0.5
+ *      Half height + 0.5
+ * The center and vector are stored in a vec4 varying ("RectEdge") with the
+ * center in the xy components and the vector in the zw components.
+ * The munged width and height are stored in a vec2 varying ("WidthHeight")
+ * with the width in x and the height in y.
+ */
+class RectGeometryProcessor : public GrGeometryProcessor {
+public:
+    RectGeometryProcessor(const SkMatrix& localMatrix) : fLocalMatrix(localMatrix) {
+        this->initClassID<RectGeometryProcessor>();
+        fInPosition    = &this->addVertexAttrib(Attribute("inPosition", kVec2f_GrVertexAttribType,
+                                                          kHigh_GrSLPrecision));
+        fInColor       = &this->addVertexAttrib(Attribute("inColor", kVec4ub_GrVertexAttribType));
+        fInRectEdge    = &this->addVertexAttrib(Attribute("inRectEdge", kVec4f_GrVertexAttribType));
+        fInWidthHeight = &this->addVertexAttrib(Attribute("inWidthHeight",
+                                                          kVec2f_GrVertexAttribType));
+    }
+
+    bool implementsDistanceVector() const override { return true; };
+
+    const Attribute* inPosition()    const { return fInPosition; }
+    const Attribute* inColor()       const { return fInColor; }
+    const Attribute* inRectEdge()    const { return fInRectEdge;    }
+    const Attribute* inWidthHeight() const { return fInWidthHeight; }
+
+    const SkMatrix& localMatrix() const { return fLocalMatrix; }
+
+    virtual ~RectGeometryProcessor() {}
+
+    const char* name() const override { return "RectEdge"; }
+
+    class GLSLProcessor : public GrGLSLGeometryProcessor {
+    public:
+        GLSLProcessor() {}
+
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) override{
+            const RectGeometryProcessor& rgp = args.fGP.cast<RectGeometryProcessor>();
+            GrGLSLVertexBuilder* vertBuilder = args.fVertBuilder;
+            GrGLSLVaryingHandler* varyingHandler = args.fVaryingHandler;
+            GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
+
+            // emit attributes
+            varyingHandler->emitAttributes(rgp);
+
+            // setup the varying for the position
+            GrGLSLVertToFrag positionVary(kVec2f_GrSLType);
+            varyingHandler->addVarying("Position", &positionVary);
+            vertBuilder->codeAppendf("%s = %s;", positionVary.vsOut(), rgp.inPosition()->fName);
+
+            // setup the varying for the center point and the unit vector that points down the
+            // height of the rect
+            GrGLSLVertToFrag rectEdgeVary(kVec4f_GrSLType);
+            varyingHandler->addVarying("RectEdge", &rectEdgeVary);
+            vertBuilder->codeAppendf("%s = %s;", rectEdgeVary.vsOut(), rgp.inRectEdge()->fName);
+
+            // setup the varying for the width/2+.5 and height/2+.5
+            GrGLSLVertToFrag widthHeightVary(kVec2f_GrSLType);
+            varyingHandler->addVarying("WidthHeight", &widthHeightVary);
+            vertBuilder->codeAppendf("%s = %s;",
+                                     widthHeightVary.vsOut(), rgp.inWidthHeight()->fName);
+
+            GrGLSLPPFragmentBuilder* fragBuilder = args.fFragBuilder;
+
+            // setup pass through color
+            varyingHandler->addPassThroughAttribute(rgp.inColor(), args.fOutputColor);
+
+            // Setup position
+            this->setupPosition(vertBuilder, gpArgs, rgp.inPosition()->fName);
+
+            // emit transforms
+            this->emitTransforms(vertBuilder,
+                                 varyingHandler,
+                                 uniformHandler,
+                                 gpArgs->fPositionVar,
+                                 rgp.inPosition()->fName,
+                                 rgp.localMatrix(),
+                                 args.fTransformsIn,
+                                 args.fTransformsOut);
+
+            // TODO: compute all these offsets, spans, and scales in the VS
+            fragBuilder->codeAppendf("float insetW = min(1.0, %s.x) - 0.5;",
+                                     widthHeightVary.fsIn());
+            fragBuilder->codeAppendf("float insetH = min(1.0, %s.y) - 0.5;",
+                                     widthHeightVary.fsIn());
+            fragBuilder->codeAppend("float outset = 0.5;");
+            // For rects > 1 pixel wide and tall the span's are noops (i.e., 1.0). For rects
+            // < 1 pixel wide or tall they serve to normalize the < 1 ramp to a 0 .. 1 range.
+            fragBuilder->codeAppend("float spanW = insetW + outset;");
+            fragBuilder->codeAppend("float spanH = insetH + outset;");
+            // For rects < 1 pixel wide or tall, these scale factors are used to cap the maximum
+            // value of coverage that is used. In other words it is the coverage that is
+            // used in the interior of the rect after the ramp.
+            fragBuilder->codeAppend("float scaleW = min(1.0, 2.0*insetW/spanW);");
+            fragBuilder->codeAppend("float scaleH = min(1.0, 2.0*insetH/spanH);");
+            // Compute the coverage for the rect's width
+            fragBuilder->codeAppendf("vec2 offset = %s.xy - %s.xy;",
+                                     positionVary.fsIn(), rectEdgeVary.fsIn());
+            fragBuilder->codeAppendf("float perpDot = abs(offset.x * %s.w - offset.y * %s.z);",
+                                     rectEdgeVary.fsIn(), rectEdgeVary.fsIn());
+
+            if (args.fDistanceVectorName) {
+                fragBuilder->codeAppendf("float widthDistance = %s.x - perpDot;",
+                                         widthHeightVary.fsIn());
+            }
+
+            fragBuilder->codeAppendf(
+                    "float coverage = scaleW*clamp((%s.x-perpDot)/spanW, 0.0, 1.0);",
+                    widthHeightVary.fsIn());
+            // Compute the coverage for the rect's height and merge with the width
+            fragBuilder->codeAppendf("perpDot = abs(dot(offset, %s.zw));",
+                                   rectEdgeVary.fsIn());
+
+            if (args.fDistanceVectorName) {
+                fragBuilder->codeAppendf("float heightDistance = %s.y - perpDot;",
+                                         widthHeightVary.fsIn());
+            }
+
+            fragBuilder->codeAppendf(
+                    "coverage = coverage*scaleH*clamp((%s.y-perpDot)/spanH, 0.0, 1.0);",
+                    widthHeightVary.fsIn());
+
+            fragBuilder->codeAppendf("%s = vec4(coverage);", args.fOutputCoverage);
+
+            if (args.fDistanceVectorName) {
+                fragBuilder->codeAppend( "// Calculating distance vector\n");
+                fragBuilder->codeAppend( "vec2 dvAxis;");
+                fragBuilder->codeAppend( "float dvLength;");
+
+                fragBuilder->codeAppend( "if (heightDistance < widthDistance) {");
+                fragBuilder->codeAppendf("    dvAxis = %s.zw;", rectEdgeVary.fsIn());
+                fragBuilder->codeAppend( "    dvLength = heightDistance;");
+                fragBuilder->codeAppend( "} else {");
+                fragBuilder->codeAppendf("    dvAxis = vec2(-%s.w, %s.z);",
+                                         rectEdgeVary.fsIn(), rectEdgeVary.fsIn());
+                fragBuilder->codeAppend( "    dvLength = widthDistance;");
+                fragBuilder->codeAppend( "}");
+
+                fragBuilder->codeAppend( "float dvSign = sign(dot(offset, dvAxis));");
+                fragBuilder->codeAppendf("%s = vec3(dvSign * dvAxis, dvLength);",
+                                         args.fDistanceVectorName);
+
+            }
+        }
+
+        static void GenKey(const GrGeometryProcessor& gp,
+                           const GrGLSLCaps&,
+                           GrProcessorKeyBuilder* b) {
+            b->add32(0x0);
+        }
+
+        void setData(const GrGLSLProgramDataManager& pdman,
+                     const GrPrimitiveProcessor& gp) override {}
+
+        void setTransformData(const GrPrimitiveProcessor& primProc,
+                              const GrGLSLProgramDataManager& pdman,
+                              int index,
+                              const SkTArray<const GrCoordTransform*, true>& transforms) override {
+            this->setTransformDataHelper<RectGeometryProcessor>(primProc, pdman, index, transforms);
+        }
+
+    private:
+        typedef GrGLSLGeometryProcessor INHERITED;
+    };
+
+    void getGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override {
+        GLSLProcessor::GenKey(*this, caps, b);
+    }
+
+    GrGLSLPrimitiveProcessor* createGLSLInstance(const GrGLSLCaps&) const override {
+        return new GLSLProcessor();
+    }
+
+private:
+    SkMatrix         fLocalMatrix;
+
+    const Attribute* fInPosition;
+    const Attribute* fInColor;
+    const Attribute* fInRectEdge;
+    const Attribute* fInWidthHeight;
+
+    GR_DECLARE_GEOMETRY_PROCESSOR_TEST;
+
+    typedef GrGeometryProcessor INHERITED;
+};
+
+GR_DEFINE_GEOMETRY_PROCESSOR_TEST(RectGeometryProcessor);
+
+sk_sp<GrGeometryProcessor> RectGeometryProcessor::TestCreate(GrProcessorTestData* d) {
+    return sk_sp<GrGeometryProcessor>(
+        new RectGeometryProcessor(GrTest::TestMatrix(d->fRandom)));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+class AnalyticRectBatch : public GrVertexBatch {
+public:
+    DEFINE_BATCH_CLASS_ID
+
+    AnalyticRectBatch(GrColor color, const SkMatrix& viewMatrix, const SkRect& rect,
+                      const SkRect& croppedRect, const SkRect& bounds)
+        : INHERITED(ClassID())
+        , fViewMatrixIfUsingLocalCoords(viewMatrix) {
+        SkPoint center = SkPoint::Make(rect.centerX(), rect.centerY());
+        viewMatrix.mapPoints(&center, 1);
+        SkScalar halfWidth = viewMatrix.mapRadius(SkScalarHalf(rect.width()));
+        SkScalar halfHeight = viewMatrix.mapRadius(SkScalarHalf(rect.height()));
+        SkVector downDir = viewMatrix.mapVector(0.0f, 1.0f);
+        downDir.normalize();
+
+        SkRect deviceSpaceCroppedRect = croppedRect;
+        viewMatrix.mapRect(&deviceSpaceCroppedRect);
+
+        fGeoData.emplace_back(Geometry {color, center, downDir, halfWidth, halfHeight,
+                                        deviceSpaceCroppedRect});
+
+        this->setBounds(bounds, HasAABloat::kYes, IsZeroArea::kNo);
+    }
+
+    const char* name() const override { return "AnalyticRectBatch"; }
+
+    SkString dumpInfo() const override {
+        SkString string;
+        for (int i = 0; i < fGeoData.count(); ++i) {
+            string.appendf("Color: 0x%08x Rect [C:(%.2f, %.2f) D:<%.2f,%.3f> W/2:%.2f H/2:%.2f]\n",
+                           fGeoData[i].fColor,
+                           fGeoData[i].fCenter.x(), fGeoData[i].fCenter.y(),
+                           fGeoData[i].fDownDir.x(), fGeoData[i].fDownDir.y(),
+                           fGeoData[i].fHalfWidth,
+                           fGeoData[i].fHalfHeight);
+        }
+        string.append(INHERITED::dumpInfo());
+        return string;
+    }
+
+    void computePipelineOptimizations(GrInitInvariantOutput* color,
+                                      GrInitInvariantOutput* coverage,
+                                      GrBatchToXPOverrides* overrides) const override {
+        // When this is called on a batch, there is only one geometry bundle
+        color->setKnownFourComponents(fGeoData[0].fColor);
+        coverage->setUnknownSingleComponent();
+    }
+
+private:
+    void initBatchTracker(const GrXPOverridesForBatch& overrides) override {
+        // Handle any overrides that affect our GP.
+        overrides.getOverrideColorIfSet(&fGeoData[0].fColor);
+        if (!overrides.readsLocalCoords()) {
+            fViewMatrixIfUsingLocalCoords.reset();
+        }
+    }
+
+    void onPrepareDraws(Target* target) const override {
+        SkMatrix localMatrix;
+        if (!fViewMatrixIfUsingLocalCoords.invert(&localMatrix)) {
+            return;
+        }
+
+        // Setup geometry processor
+        SkAutoTUnref<GrGeometryProcessor> gp(new RectGeometryProcessor(localMatrix));
+
+        int instanceCount = fGeoData.count();
+        size_t vertexStride = gp->getVertexStride();
+        SkASSERT(vertexStride == sizeof(RectVertex));
+        QuadHelper helper;
+        RectVertex* verts = reinterpret_cast<RectVertex*>(helper.init(target, vertexStride,
+                                                                      instanceCount));
+        if (!verts) {
+            return;
+        }
+
+        for (int i = 0; i < instanceCount; i++) {
+            const Geometry& geom = fGeoData[i];
+
+            GrColor  color       = geom.fColor;
+            SkPoint  center      = geom.fCenter;
+            SkVector downDir     = geom.fDownDir;
+            SkScalar halfWidth   = geom.fHalfWidth;
+            SkScalar halfHeight  = geom.fHalfHeight;
+            SkRect   croppedRect = geom.fCroppedRect;
+
+            SkVector rightDir;
+            downDir.rotateCCW(&rightDir);
+
+            verts[0].fPos = {croppedRect.fLeft, croppedRect.fTop};
+            verts[0].fColor = color;
+            verts[0].fCenter = center;
+            verts[0].fDownDir = downDir;
+            verts[0].fHalfWidth = halfWidth;
+            verts[0].fHalfHeight = halfHeight;
+
+            verts[1].fPos = {croppedRect.fRight, croppedRect.fTop};
+            verts[1].fColor = color;
+            verts[1].fCenter = center;
+            verts[1].fDownDir = downDir;
+            verts[1].fHalfWidth = halfWidth;
+            verts[1].fHalfHeight = halfHeight;
+
+            verts[2].fPos = {croppedRect.fRight, croppedRect.fBottom};
+            verts[2].fColor = color;
+            verts[2].fCenter = center;
+            verts[2].fDownDir = downDir;
+            verts[2].fHalfWidth = halfWidth;
+            verts[2].fHalfHeight = halfHeight;
+
+            verts[3].fPos = {croppedRect.fLeft, croppedRect.fBottom};
+            verts[3].fColor = color;
+            verts[3].fCenter = center;
+            verts[3].fDownDir = downDir;
+            verts[3].fHalfWidth = halfWidth;
+            verts[3].fHalfHeight = halfHeight;
+
+            verts += kVerticesPerQuad;
+        }
+        helper.recordDraw(target, gp);
+    }
+
+    bool onCombineIfPossible(GrBatch* t, const GrCaps& caps) override {
+        AnalyticRectBatch* that = t->cast<AnalyticRectBatch>();
+        if (!GrPipeline::CanCombine(*this->pipeline(), this->bounds(), *that->pipeline(),
+                                    that->bounds(), caps)) {
+            return false;
+        }
+
+        if (!fViewMatrixIfUsingLocalCoords.cheapEqualTo(that->fViewMatrixIfUsingLocalCoords)) {
+            return false;
+        }
+
+        fGeoData.push_back_n(that->fGeoData.count(), that->fGeoData.begin());
+        this->joinBounds(*that);
+        return true;
+    }
+
+    struct Geometry {
+        GrColor  fColor;
+        SkPoint  fCenter;
+        SkVector fDownDir;
+        SkScalar fHalfWidth;
+        SkScalar fHalfHeight;
+        SkRect   fCroppedRect;
+    };
+
+    SkMatrix                     fViewMatrixIfUsingLocalCoords;
+    SkSTArray<1, Geometry, true> fGeoData;
+
+    typedef GrVertexBatch INHERITED;
+};
+
+GrDrawBatch* GrAnalyticRectBatch::CreateAnalyticRectBatch(GrColor color,
+                                                          const SkMatrix& viewMatrix,
+                                                          const SkRect& rect,
+                                                          const SkRect& croppedRect,
+                                                          const SkRect& bounds) {
+    return new AnalyticRectBatch(color, viewMatrix, rect, croppedRect, bounds);
+}
+
+#ifdef GR_TEST_UTILS
+
+DRAW_BATCH_TEST_DEFINE(AnalyticRectBatch) {
+    SkMatrix viewMatrix = GrTest::TestMatrix(random);
+    GrColor color = GrRandomColor(random);
+    SkRect rect = GrTest::TestSquare(random);
+    SkRect croppedRect = GrTest::TestSquare(random);
+    SkRect bounds = GrTest::TestSquare(random);
+    return new AnalyticRectBatch(color, viewMatrix, rect, croppedRect, bounds);
+}
+
+#endif