gm/beziereffects.cpp

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

// This test only works with the GPU backend.

#include "gm.h"

#if SK_SUPPORT_GPU

#include "GrContext.h"
#include "GrPathUtils.h"
#include "GrTest.h"
#include "SkColorPriv.h"
#include "SkDevice.h"
#include "SkGeometry.h"

#include "effects/GrBezierEffect.h"

// Position & KLM line eq values. These are the vertex attributes for Bezier curves. The last value
// of the Vec4f is ignored.
namespace {
extern const GrVertexAttrib kAttribs[] = {
    {kVec2f_GrVertexAttribType, 0, kPosition_GrVertexAttribBinding},
    {kVec4f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding}
};
}

static inline SkScalar eval_line(const SkPoint& p, const SkScalar lineEq[3], SkScalar sign) {
    return sign * (lineEq[0] * p.fX + lineEq[1] * p.fY + lineEq[2]);
}

namespace skiagm {
/**
 * This GM directly exercises effects that draw Bezier curves in the GPU backend.
 */
class BezierCubicEffects : public GM {
public:
    BezierCubicEffects() {
        this->setBGColor(0xFFFFFFFF);
    }

protected:
    virtual SkString onShortName() SK_OVERRIDE {
        return SkString("bezier_cubic_effects");
    }

    virtual SkISize onISize() SK_OVERRIDE {
        return make_isize(800, 800);
    }

    virtual uint32_t onGetFlags() const SK_OVERRIDE {
        // This is a GPU-specific GM.
        return kGPUOnly_Flag;
    }


    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
        SkBaseDevice* device = canvas->getTopDevice();
        GrRenderTarget* rt = device->accessRenderTarget();
        if (NULL == rt) {
            return;
        }
        GrContext* context = rt->getContext();
        if (NULL == context) {
            return;
        }

        struct Vertex {
            SkPoint fPosition;
            float   fKLM[4]; // The last value is ignored. The effect expects a vec4f.
        };

        static const int kNumCubics = 15;
        SkRandom rand;

        // Mult by 3 for each edge effect type
        int numCols = SkScalarCeilToInt(SkScalarSqrt(SkIntToScalar(kNumCubics*3)));
        int numRows = SkScalarCeilToInt(SkIntToScalar(kNumCubics*3) / numCols);
        SkScalar w = SkIntToScalar(rt->width()) / numCols;
        SkScalar h = SkIntToScalar(rt->height()) / numRows;
        int row = 0;
        int col = 0;

        for (int i = 0; i < kNumCubics; ++i) {
            SkPoint baseControlPts[] = {
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)}
            };
            for(int edgeType = kFillAA_GrBezierEdgeType; edgeType < 3; ++edgeType) {
                SkScalar x = SkScalarMul(col, w);
                SkScalar y = SkScalarMul(row, h);
                SkPoint controlPts[] = {
                    {x + baseControlPts[0].fX, y + baseControlPts[0].fY},
                    {x + baseControlPts[1].fX, y + baseControlPts[1].fY},
                    {x + baseControlPts[2].fX, y + baseControlPts[2].fY},
                    {x + baseControlPts[3].fX, y + baseControlPts[3].fY}
                };
                SkPoint chopped[10];
                SkScalar klmEqs[9];
                SkScalar klmSigns[3];
                int cnt = GrPathUtils::chopCubicAtLoopIntersection(controlPts,
                                                                   chopped,
                                                                   klmEqs,
                                                                   klmSigns);

                SkPaint ctrlPtPaint;
                ctrlPtPaint.setColor(rand.nextU() | 0xFF000000);
                for (int i = 0; i < 4; ++i) {
                    canvas->drawCircle(controlPts[i].fX, controlPts[i].fY, 6.f, ctrlPtPaint);
                }

                SkPaint polyPaint;
                polyPaint.setColor(0xffA0A0A0);
                polyPaint.setStrokeWidth(0);
                polyPaint.setStyle(SkPaint::kStroke_Style);
                canvas->drawPoints(SkCanvas::kPolygon_PointMode, 4, controlPts, polyPaint);

                SkPaint choppedPtPaint;
                choppedPtPaint.setColor(~ctrlPtPaint.getColor() | 0xFF000000);

                for (int c = 0; c < cnt; ++c) {
                    SkPoint* pts = chopped + 3 * c;

                    for (int i = 0; i < 4; ++i) {
                        canvas->drawCircle(pts[i].fX, pts[i].fY, 3.f, choppedPtPaint);
                    }

                    SkRect bounds;
                    bounds.set(pts, 4);

                    SkPaint boundsPaint;
                    boundsPaint.setColor(0xff808080);
                    boundsPaint.setStrokeWidth(0);
                    boundsPaint.setStyle(SkPaint::kStroke_Style);
                    canvas->drawRect(bounds, boundsPaint);

                    Vertex verts[4];
                    verts[0].fPosition.setRectFan(bounds.fLeft, bounds.fTop,
                                                  bounds.fRight, bounds.fBottom,
                                                  sizeof(Vertex));
                    for (int v = 0; v < 4; ++v) {
                        verts[v].fKLM[0] = eval_line(verts[v].fPosition, klmEqs + 0, klmSigns[c]);
                        verts[v].fKLM[1] = eval_line(verts[v].fPosition, klmEqs + 3, klmSigns[c]);
                        verts[v].fKLM[2] = eval_line(verts[v].fPosition, klmEqs + 6, 1.f);
                    }

                    GrTestTarget tt;
                    context->getTestTarget(&tt);
                    if (NULL == tt.target()) {
                        continue;
                    }
                    GrDrawState* drawState = tt.target()->drawState();
                    drawState->setVertexAttribs<kAttribs>(2);

                    SkAutoTUnref<GrEffectRef> effect(GrCubicEffect::Create(
                            GrBezierEdgeType(edgeType), *tt.target()->caps()));
                    if (!effect) {
                        continue;
                    }
                    drawState->addCoverageEffect(effect, 1);
                    drawState->setRenderTarget(rt);
                    drawState->setColor(0xff000000);

                    tt.target()->setVertexSourceToArray(verts, 4);
                    tt.target()->setIndexSourceToBuffer(context->getQuadIndexBuffer());
                    tt.target()->drawIndexed(kTriangleFan_GrPrimitiveType, 0, 0, 4, 6);
                }
                ++col;
                if (numCols == col) {
                    col = 0;
                    ++row;
                }
            }
        }
    }

private:
    typedef GM INHERITED;
};

//////////////////////////////////////////////////////////////////////////////

/**
 * This GM directly exercises effects that draw Bezier curves in the GPU backend.
 */
class BezierConicEffects : public GM {
public:
    BezierConicEffects() {
        this->setBGColor(0xFFFFFFFF);
    }

protected:
    virtual SkString onShortName() SK_OVERRIDE {
        return SkString("bezier_conic_effects");
    }

    virtual SkISize onISize() SK_OVERRIDE {
        return make_isize(800, 800);
    }

    virtual uint32_t onGetFlags() const SK_OVERRIDE {
        // This is a GPU-specific GM.
        return kGPUOnly_Flag;
    }


    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
        SkBaseDevice* device = canvas->getTopDevice();
        GrRenderTarget* rt = device->accessRenderTarget();
        if (NULL == rt) {
            return;
        }
        GrContext* context = rt->getContext();
        if (NULL == context) {
            return;
        }

        struct Vertex {
            SkPoint fPosition;
            float   fKLM[4]; // The last value is ignored. The effect expects a vec4f.
        };

        static const int kNumConics = 10;
        SkRandom rand;

        // Mult by 3 for each edge effect type
        int numCols = SkScalarCeilToInt(SkScalarSqrt(SkIntToScalar(kNumConics*3)));
        int numRows = SkScalarCeilToInt(SkIntToScalar(kNumConics*3) / numCols);
        SkScalar w = SkIntToScalar(rt->width()) / numCols;
        SkScalar h = SkIntToScalar(rt->height()) / numRows;
        int row = 0;
        int col = 0;

        for (int i = 0; i < kNumConics; ++i) {
            SkPoint baseControlPts[] = {
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)}
            };
            SkScalar weight = rand.nextRangeF(0.f, 2.f);
            for(int edgeType = kFillAA_GrBezierEdgeType; edgeType < 3; ++edgeType) {
                SkScalar x = SkScalarMul(col, w);
                SkScalar y = SkScalarMul(row, h);
                SkPoint controlPts[] = {
                    {x + baseControlPts[0].fX, y + baseControlPts[0].fY},
                    {x + baseControlPts[1].fX, y + baseControlPts[1].fY},
                    {x + baseControlPts[2].fX, y + baseControlPts[2].fY}
                };
                SkConic dst[4];
                SkScalar klmEqs[9];
                int cnt = chop_conic(controlPts, dst, weight);
                GrPathUtils::getConicKLM(controlPts, weight, klmEqs);

                SkPaint ctrlPtPaint;
                ctrlPtPaint.setColor(rand.nextU() | 0xFF000000);
                for (int i = 0; i < 3; ++i) {
                    canvas->drawCircle(controlPts[i].fX, controlPts[i].fY, 6.f, ctrlPtPaint);
                }

                SkPaint polyPaint;
                polyPaint.setColor(0xffA0A0A0);
                polyPaint.setStrokeWidth(0);
                polyPaint.setStyle(SkPaint::kStroke_Style);
                canvas->drawPoints(SkCanvas::kPolygon_PointMode, 3, controlPts, polyPaint);

                SkPaint choppedPtPaint;
                choppedPtPaint.setColor(~ctrlPtPaint.getColor() | 0xFF000000);

                for (int c = 0; c < cnt; ++c) {
                    SkPoint* pts = dst[c].fPts;
                    for (int i = 0; i < 3; ++i) {
                        canvas->drawCircle(pts[i].fX, pts[i].fY, 3.f, choppedPtPaint);
                    }

                    SkRect bounds;
                    //SkPoint bPts[] = {{0.f, 0.f}, {800.f, 800.f}};
                    //bounds.set(bPts, 2);
                    bounds.set(pts, 3);

                    SkPaint boundsPaint;
                    boundsPaint.setColor(0xff808080);
                    boundsPaint.setStrokeWidth(0);
                    boundsPaint.setStyle(SkPaint::kStroke_Style);
                    canvas->drawRect(bounds, boundsPaint);

                    Vertex verts[4];
                    verts[0].fPosition.setRectFan(bounds.fLeft, bounds.fTop,
                                                  bounds.fRight, bounds.fBottom,
                                                  sizeof(Vertex));
                    for (int v = 0; v < 4; ++v) {
                        verts[v].fKLM[0] = eval_line(verts[v].fPosition, klmEqs + 0, 1.f);
                        verts[v].fKLM[1] = eval_line(verts[v].fPosition, klmEqs + 3, 1.f);
                        verts[v].fKLM[2] = eval_line(verts[v].fPosition, klmEqs + 6, 1.f);
                    }

                    GrTestTarget tt;
                    context->getTestTarget(&tt);
                    if (NULL == tt.target()) {
                        continue;
                    }
                    GrDrawState* drawState = tt.target()->drawState();
                    drawState->setVertexAttribs<kAttribs>(2);

                    SkAutoTUnref<GrEffectRef> effect(GrConicEffect::Create(
                            GrBezierEdgeType(edgeType), *tt.target()->caps()));
                    if (!effect) {
                        continue;
                    }
                    drawState->addCoverageEffect(effect, 1);
                    drawState->setRenderTarget(rt);
                    drawState->setColor(0xff000000);

                    tt.target()->setVertexSourceToArray(verts, 4);
                    tt.target()->setIndexSourceToBuffer(context->getQuadIndexBuffer());
                    tt.target()->drawIndexed(kTriangleFan_GrPrimitiveType, 0, 0, 4, 6);
                }
                ++col;
                if (numCols == col) {
                    col = 0;
                    ++row;
                }
            }
        }
    }

private:
    // Uses the max curvature function for quads to estimate
    // where to chop the conic. If the max curvature is not
    // found along the curve segment it will return 1 and
    // dst[0] is the original conic. If it returns 2 the dst[0]
    // and dst[1] are the two new conics.
    int split_conic(const SkPoint src[3], SkConic dst[2], const SkScalar weight) {
        SkScalar t = SkFindQuadMaxCurvature(src);
        if (t == 0) {
            if (dst) {
                dst[0].set(src, weight);
            }
            return 1;
        } else {
            if (dst) {
                SkConic conic;
                conic.set(src, weight);
                conic.chopAt(t, dst);
            }
            return 2;
        }
    }

    // Calls split_conic on the entire conic and then once more on each subsection.
    // Most cases will result in either 1 conic (chop point is not within t range)
    // or 3 points (split once and then one subsection is split again).
    int chop_conic(const SkPoint src[3], SkConic dst[4], const SkScalar weight) {
        SkConic dstTemp[2];
        int conicCnt = split_conic(src, dstTemp, weight);
        if (2 == conicCnt) {
            int conicCnt2 = split_conic(dstTemp[0].fPts, dst, dstTemp[0].fW);
            conicCnt = conicCnt2 + split_conic(dstTemp[1].fPts, &dst[conicCnt2], dstTemp[1].fW);
        } else {
            dst[0] = dstTemp[0];
        }
        return conicCnt;
    }

    typedef GM INHERITED;
};

//////////////////////////////////////////////////////////////////////////////
/**
 * This GM directly exercises effects that draw Bezier quad curves in the GPU backend.
 */
class BezierQuadEffects : public GM {
public:
    BezierQuadEffects() {
        this->setBGColor(0xFFFFFFFF);
    }

protected:
    virtual SkString onShortName() SK_OVERRIDE {
        return SkString("bezier_quad_effects");
    }

    virtual SkISize onISize() SK_OVERRIDE {
        return make_isize(800, 800);
    }

    virtual uint32_t onGetFlags() const SK_OVERRIDE {
        // This is a GPU-specific GM.
        return kGPUOnly_Flag;
    }


    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
        SkBaseDevice* device = canvas->getTopDevice();
        GrRenderTarget* rt = device->accessRenderTarget();
        if (NULL == rt) {
            return;
        }
        GrContext* context = rt->getContext();
        if (NULL == context) {
            return;
        }

        struct Vertex {
            SkPoint fPosition;
            float   fUV[4]; // The last two values are ignored. The effect expects a vec4f.
        };

        static const int kNumQuads = 5;
        SkRandom rand;

        int numCols = SkScalarCeilToInt(SkScalarSqrt(SkIntToScalar(kNumQuads*3)));
        int numRows = SkScalarCeilToInt(SkIntToScalar(kNumQuads*3) / numCols);
        SkScalar w = SkIntToScalar(rt->width()) / numCols;
        SkScalar h = SkIntToScalar(rt->height()) / numRows;
        int row = 0;
        int col = 0;

        for (int i = 0; i < kNumQuads; ++i) {
            SkPoint baseControlPts[] = {
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)},
                {rand.nextRangeF(0.f, w), rand.nextRangeF(0.f, h)}
            };
            for(int edgeType = kFillAA_GrBezierEdgeType; edgeType < 3; ++edgeType) {
                SkScalar x = SkScalarMul(col, w);
                SkScalar y = SkScalarMul(row, h);
                SkPoint controlPts[] = {
                    {x + baseControlPts[0].fX, y + baseControlPts[0].fY},
                    {x + baseControlPts[1].fX, y + baseControlPts[1].fY},
                    {x + baseControlPts[2].fX, y + baseControlPts[2].fY}
                };
                SkPoint chopped[5];
                int cnt = SkChopQuadAtMaxCurvature(controlPts, chopped);

                SkPaint ctrlPtPaint;
                ctrlPtPaint.setColor(rand.nextU() | 0xFF000000);
                for (int i = 0; i < 3; ++i) {
                    canvas->drawCircle(controlPts[i].fX, controlPts[i].fY, 6.f, ctrlPtPaint);
                }

                SkPaint polyPaint;
                polyPaint.setColor(0xffA0A0A0);
                polyPaint.setStrokeWidth(0);
                polyPaint.setStyle(SkPaint::kStroke_Style);
                canvas->drawPoints(SkCanvas::kPolygon_PointMode, 3, controlPts, polyPaint);

                SkPaint choppedPtPaint;
                choppedPtPaint.setColor(~ctrlPtPaint.getColor() | 0xFF000000);

                for (int c = 0; c < cnt; ++c) {
                    SkPoint* pts = chopped + 2 * c;

                    for (int i = 0; i < 3; ++i) {
                        canvas->drawCircle(pts[i].fX, pts[i].fY, 3.f, choppedPtPaint);
                    }

                    SkRect bounds;
                    bounds.set(pts, 3);

                    SkPaint boundsPaint;
                    boundsPaint.setColor(0xff808080);
                    boundsPaint.setStrokeWidth(0);
                    boundsPaint.setStyle(SkPaint::kStroke_Style);
                    canvas->drawRect(bounds, boundsPaint);

                    Vertex verts[4];
                    verts[0].fPosition.setRectFan(bounds.fLeft, bounds.fTop,
                                                  bounds.fRight, bounds.fBottom,
                                                  sizeof(Vertex));

                    GrPathUtils::QuadUVMatrix DevToUV(pts);
                    DevToUV.apply<4, sizeof(Vertex), sizeof(GrPoint)>(verts);

                    GrTestTarget tt;
                    context->getTestTarget(&tt);
                    if (NULL == tt.target()) {
                        continue;
                    }
                    GrDrawState* drawState = tt.target()->drawState();
                    drawState->setVertexAttribs<kAttribs>(2);
                    SkAutoTUnref<GrEffectRef> effect(GrQuadEffect::Create(
                            GrBezierEdgeType(edgeType), *tt.target()->caps()));
                    if (!effect) {
                        continue;
                    }
                    drawState->addCoverageEffect(effect, 1);
                    drawState->setRenderTarget(rt);
                    drawState->setColor(0xff000000);

                    tt.target()->setVertexSourceToArray(verts, 4);
                    tt.target()->setIndexSourceToBuffer(context->getQuadIndexBuffer());
                    tt.target()->drawIndexed(kTriangles_GrPrimitiveType, 0, 0, 4, 6);
                }
                ++col;
                if (numCols == col) {
                    col = 0;
                    ++row;
                }
            }
        }
    }

private:
    typedef GM INHERITED;
};

DEF_GM( return SkNEW(BezierCubicEffects); )
DEF_GM( return SkNEW(BezierConicEffects); )
DEF_GM( return SkNEW(BezierQuadEffects); )

}

#endif