samplecode/SampleVertices.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "Sample.h"
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkGradientShader.h"
#include "SkGraphics.h"
#include "SkPath.h"
#include "SkRandom.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkUTF.h"
#include "SkColorPriv.h"
#include "SkColorFilter.h"
#include "SkTime.h"
#include "SkTypeface.h"
#include "SkVertices.h"

#include "SkOSFile.h"
#include "SkStream.h"

static sk_sp<SkShader> make_shader0(SkIPoint* size) {
    SkBitmap    bm;
    size->set(2, 2);
    SkPMColor color0 = SkPreMultiplyARGB(0x80, 0x80, 0xff, 0x80);
    SkPMColor color1 = SkPreMultiplyARGB(0x40, 0xff, 0x00, 0xff);
    bm.allocN32Pixels(size->fX, size->fY);
    bm.eraseColor(color0);
    uint32_t* pixels = (uint32_t*) bm.getPixels();
    pixels[0] = pixels[2] = color0;
    pixels[1] = pixels[3] = color1;

    return SkShader::MakeBitmapShader(bm, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
}

static sk_sp<SkShader> make_shader1(const SkIPoint& size) {
    SkPoint pts[] = { { 0, 0 },
                      { SkIntToScalar(size.fX), SkIntToScalar(size.fY) } };
    SkColor colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorRED };
    return SkGradientShader::MakeLinear(pts, colors, nullptr,
                    SK_ARRAY_COUNT(colors), SkShader::kMirror_TileMode);
}

class VerticesView : public Sample {
    sk_sp<SkShader> fShader0;
    sk_sp<SkShader> fShader1;

public:
    VerticesView() {
        SkIPoint    size;

        fShader0 = make_shader0(&size);
        fShader1 = make_shader1(size);

        make_strip(&fRecs[0], size.fX, size.fY);
        make_fan(&fRecs[1], size.fX, size.fY);
        make_tris(&fRecs[2]);

        fScale = SK_Scalar1;

        this->setBGColor(SK_ColorGRAY);
    }

protected:
    bool onQuery(Sample::Event* evt) override {
        if (Sample::TitleQ(*evt)) {
            Sample::TitleR(evt, "Vertices");
            return true;
        }
        return this->INHERITED::onQuery(evt);
    }

    SkScalar fScale;

    void onDrawContent(SkCanvas* canvas) override {
        SkPaint paint;
        paint.setDither(true);
        paint.setFilterQuality(kLow_SkFilterQuality);

        for (size_t i = 0; i < SK_ARRAY_COUNT(fRecs); i++) {
            auto verts = SkVertices::MakeCopy(fRecs[i].fMode, fRecs[i].fCount,
                                              fRecs[i].fVerts, fRecs[i].fTexs,
                                              nullptr);
            canvas->save();

            paint.setShader(nullptr);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader0);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader1);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);
            canvas->restore();

            canvas->translate(0, SkIntToScalar(250));
        }
    }

    Sample::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned) override {
        return new Click(this);
    }

    bool onClick(Click* click) override {
    //    fCurrX = click->fICurr.fX;
    //    fCurrY = click->fICurr.fY;
        return true;
    }

private:
    struct Rec {
        SkVertices::VertexMode  fMode;
        int                     fCount;
        SkPoint*                fVerts;
        SkPoint*                fTexs;

        Rec() : fCount(0), fVerts(nullptr), fTexs(nullptr) {}
        ~Rec() { delete[] fVerts; delete[] fTexs; }
    };

    void make_tris(Rec* rec) {
        int n = 10;
        SkRandom    rand;

        rec->fMode = SkVertices::kTriangles_VertexMode;
        rec->fCount = n * 3;
        rec->fVerts = new SkPoint[rec->fCount];

        for (int i = 0; i < n; i++) {
            SkPoint* v = &rec->fVerts[i*3];
            for (int j = 0; j < 3; j++) {
                v[j].set(rand.nextUScalar1() * 250, rand.nextUScalar1() * 250);
            }
        }
    }

    void make_fan(Rec* rec, int texWidth, int texHeight) {
        const SkScalar tx = SkIntToScalar(texWidth);
        const SkScalar ty = SkIntToScalar(texHeight);
        const int n = 24;

        rec->fMode = SkVertices::kTriangleFan_VertexMode;
        rec->fCount = n + 2;
        rec->fVerts = new SkPoint[rec->fCount];
        rec->fTexs  = new SkPoint[rec->fCount];

        SkPoint* v = rec->fVerts;
        SkPoint* t = rec->fTexs;

        v[0].set(0, 0);
        t[0].set(0, 0);
        for (int i = 0; i < n; i++) {
            SkScalar cos;
            SkScalar sin = SkScalarSinCos(SK_ScalarPI * 2 * i / n, &cos);
            v[i+1].set(cos, sin);
            t[i+1].set(i*tx/n, ty);
        }
        v[n+1] = v[1];
        t[n+1].set(tx, ty);

        SkMatrix m;
        m.setScale(SkIntToScalar(100), SkIntToScalar(100));
        m.postTranslate(SkIntToScalar(110), SkIntToScalar(110));
        m.mapPoints(v, rec->fCount);
    }

    void make_strip(Rec* rec, int texWidth, int texHeight) {
        const SkScalar tx = SkIntToScalar(texWidth);
        const SkScalar ty = SkIntToScalar(texHeight);
        const int n = 24;

        rec->fMode = SkVertices::kTriangleStrip_VertexMode;
        rec->fCount = 2 * (n + 1);
        rec->fVerts = new SkPoint[rec->fCount];
        rec->fTexs  = new SkPoint[rec->fCount];

        SkPoint* v = rec->fVerts;
        SkPoint* t = rec->fTexs;

        for (int i = 0; i < n; i++) {
            SkScalar cos;
            SkScalar sin = SkScalarSinCos(SK_ScalarPI * 2 * i / n, &cos);
            v[i*2 + 0].set(cos/2, sin/2);
            v[i*2 + 1].set(cos, sin);

            t[i*2 + 0].set(tx * i / n, ty);
            t[i*2 + 1].set(tx * i / n, 0);
        }
        v[2*n + 0] = v[0];
        v[2*n + 1] = v[1];

        t[2*n + 0].set(tx, ty);
        t[2*n + 1].set(tx, 0);

        SkMatrix m;
        m.setScale(SkIntToScalar(100), SkIntToScalar(100));
        m.postTranslate(SkIntToScalar(110), SkIntToScalar(110));
        m.mapPoints(v, rec->fCount);
    }

    Rec fRecs[3];

    typedef Sample INHERITED;
};

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

DEF_SAMPLE( return new VerticesView(); )