Making a sample for shadow maps for more intensive development

samplecode/SampleShadowing.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 "gm.h"
+#include "SampleCode.h"

[robertphillips, 2016/08/02 16:05:06]

Do we need SkDrawFilter.h ?

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+#include "SkDrawFilter.h"
+#include "SkNormalSource.h"

[robertphillips, 2016/08/02 16:05:06]

Same for SkPathEffect.h

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+#include "SkPathEffect.h"
+#include "SkPictureRecorder.h"
+#include "SkSurface.h"
+#include "SkShadowPaintFilterCanvas.h"
+#include "SkShadowShader.h"
+
+#ifdef SK_EXPERIMENTAL_SHADOWING
+
+constexpr int NUM_TEST_RECTS = 3;
+
+static sk_sp<SkShader> make_shadow_shader(sk_sp<SkImage> povDepth,
+                                          sk_sp<SkImage> diffuse,
+                                          sk_sp<SkLights> lights) {
+
+    sk_sp<SkShader> povDepthShader = povDepth->makeShader(SkShader::kClamp_TileMode,
+                                                          SkShader::kClamp_TileMode);
+
+    sk_sp<SkShader> diffuseShader = diffuse->makeShader(SkShader::kClamp_TileMode,
+                                                        SkShader::kClamp_TileMode);
+
+    return SkShadowShader::Make(std::move(povDepthShader),
+                                std::move(diffuseShader),
+                                std::move(lights),
+                                diffuse->width(), diffuse->height());
+}
+
+
+class IndexClick : public SkView::Click {
+    int fIndex;
+public:

[robertphillips, 2016/08/02 16:05:06]

add INHERITED and use it here

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+    IndexClick(SkView* v, int index) : SkView::Click(v), fIndex(index) {}
+
+    static int GetIndex(SkView::Click* click) {
+        return ((IndexClick*)click)->fIndex;
+    }
+};
+
+class ShadowingView : public SampleView {
+    enum {
+        kZoom = 96
+    };
+
+public:
+    ShadowingView() {
+
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));
+        SkLights::Builder builder;
+        builder.add(SkLights::Light(SkColor3f::Make(0.1f, 0.2f, 0.3f),
+                                    SkVector3::Make(0.27f, 0.07f, 1.0f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.3f, 0.2f, 0.1f),
+                                    SkVector3::Make(0.03f, 0.27f, 1.0f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.2f, 0.15f, 0.1f),
+                                    SkVector3::Make(0.21f, 0.21f, 1.0f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.1f, 0.15f, 0.2f),
+                                    SkVector3::Make(0.09f, 0.09f, 1.0f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.3f, 0.3f, 0.3f)));
+        this->fLights = builder.finish();
+

[robertphillips, 2016/08/02 16:05:07]

don't need this-> on member variables

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+        this->fColors[0] = 0xFFEE8888;
+        this->fDepths[0] = 80;
+        this->fRects[0] = SkRect::MakeLTRB(200,150,350,300);
+
+        this->fColors[1] = 0xFF88EE88;
+        this->fDepths[1] = 160;
+        this->fRects[1] = SkRect::MakeLTRB(150,200,300,350);
+
+        this->fColors[2] = 0xFF8888EE;
+        this->fDepths[2] = 240;
+        this->fRects[2] = SkRect::MakeLTRB(100,100,250,250);
+    }
+
+protected:
+    static const int kWidth = 400;
+    static const int kHeight = 400;
+    SkRect fRects[NUM_TEST_RECTS];
+    int fDepths[NUM_TEST_RECTS];
+    SkColor fColors[NUM_TEST_RECTS];
+    int fSelectedRect = -1;
+    bool fMoveLight = false;
+
+    bool onQuery(SkEvent *evt) override {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "shadowing");
+            return true;
+        }
+
+        SkUnichar uni;
+        if (SampleCode::CharQ(*evt, &uni)) {
+            switch (uni) {
+                case 'L':
+                    fMoveLight = !fMoveLight;
+                    break;
+                default:
+                    break;
+            }
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+

[robertphillips, 2016/08/02 16:05:06]

This is file static naming. You either need to make it file static or change the
style.

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+    sk_sp<SkPicture> make_test_picture(int width, int height) {
+        SkPictureRecorder recorder;
+
+        // LONG RANGE TODO: eventually add SkBBHFactory (bounding box factory)
+        SkCanvas* canvas = recorder.beginRecording(SkRect::MakeIWH(width, height));
+
+        SkASSERT(canvas->getTotalMatrix().isIdentity());
+        SkPaint paint;
+        paint.setColor(SK_ColorGRAY);
+
+        // LONG RANGE TODO: tag occluders
+        // LONG RANGE TODO: track number of IDs we need (hopefully less than 256)
+        //                  and determinate the mapping from z to id
+
+        // universal receiver, "ground"
+        canvas->drawRect(SkRect::MakeIWH(width, height), paint);
+
+        for (int i = 0; i < NUM_TEST_RECTS; i++) {
+            paint.setColor(fColors[i]);
+            if (i == 0) {
+                canvas->translateZ(fDepths[0]);
+            } else {
+                canvas->translateZ(fDepths[i] - fDepths[i-1]);
+            }
+            canvas->drawRect(fRects[i], paint);
+        }
+
+        return recorder.finishRecordingAsPicture();
+    }
+

[robertphillips, 2016/08/02 16:05:07]

SkTMin ?

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+#define MIN(x,y) ((x) > (y) ? (y) : (x))
+    void onDrawContent(SkCanvas *canvas) override {
+        // This picture stores the picture of the scene.
+        // It's used to generate the depth maps.

[robertphillips, 2016/08/02 16:05:06]

Do you need to recreate this every time ?

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+        sk_sp<SkPicture> pic(make_test_picture(kWidth, kHeight));
+

[robertphillips, 2016/08/02 16:05:07]

Don't you only need to recreate the shadow map if a light or part of the scene
moves ?

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+        for (int i = 0; i < fLights->numLights(); ++i) {
+            // skip over ambient lights; they don't cast shadows
+            if (SkLights::Light::kAmbient_LightType == fLights->light(i).type()) {
+                continue;
+            }
+
+            // TODO: maybe add a kDepth_8_SkColorType when vertices have depth
+
+            SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
+                                                 kBGRA_8888_SkColorType,
+                                                 kOpaque_SkAlphaType);
+
+            // Create a new surface (that matches the backend of canvas)
+            // for each shadow map
+            sk_sp<SkSurface> surf(canvas->makeSurface(info));
+
+            // Wrap another SPFCanvas around the surface
+            sk_sp<SkShadowPaintFilterCanvas> depthMapCanvas =
+                    sk_make_sp<SkShadowPaintFilterCanvas>(surf->getCanvas());
+
+            // set the depth map canvas to have the light we're drawing.
+            SkLights::Builder builder;
+            builder.add(fLights->light(i));
+            sk_sp<SkLights> curLight = builder.finish();
+
+            depthMapCanvas->setLights(std::move(curLight));
+            depthMapCanvas->drawPicture(pic);
+
+            fLights->light(i).setShadowMap(surf->makeImageSnapshot());
+        }
+
+        sk_sp<SkImage> povDepthMap;
+        sk_sp<SkImage> diffuseMap;
+
+        // TODO: pass the depth to the shader in vertices, or uniforms
+        //       so we don't have to render depth and color separately
+
+        // povDepthMap
+        {
+            SkLights::Builder builder;
+            builder.add(SkLights::Light(SkColor3f::Make(1.0f, 1.0f, 1.0f),
+                                        SkVector3::Make(0.0f, 0.0f, 1.0f)));
+            sk_sp<SkLights> povLight = builder.finish();
+
+            SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
+                                                 kBGRA_8888_SkColorType,
+                                                 kOpaque_SkAlphaType);
+
+            // Create a new surface (that matches the backend of canvas)
+            // to create the povDepthMap
+            sk_sp<SkSurface> surf(canvas->makeSurface(info));
+
+            // Wrap another SPFCanvas around the surface
+            sk_sp<SkShadowPaintFilterCanvas> depthMapCanvas =
+                    sk_make_sp<SkShadowPaintFilterCanvas>(surf->getCanvas());
+
+            // set the depth map canvas to have the light as the user's POV
+            depthMapCanvas->setLights(std::move(povLight));
+
+            depthMapCanvas->drawPicture(pic);
+
+            povDepthMap = surf->makeImageSnapshot();
+        }
+
+        // diffuseMap
+        {
+            SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
+                                                 kBGRA_8888_SkColorType,
+                                                 kOpaque_SkAlphaType);
+
+            sk_sp<SkSurface> surf(canvas->makeSurface(info));
+            surf->getCanvas()->drawPicture(pic);
+
+            diffuseMap = surf->makeImageSnapshot();
+        }
+
+        SkPaint paint;
+        paint.setShader(make_shadow_shader(std::move(povDepthMap),
+                                           std::move(diffuseMap),
+                                           fLights));
+
+        canvas->drawRect(SkRect::MakeIWH(kWidth, kHeight), paint);
+    }
+
+    SkView::Click* onFindClickHandler(SkScalar x, SkScalar y, unsigned modi) override {
+        int index = 0;
+
+        return new IndexClick(this, index);
+    }
+
+    bool onClick(Click *click) override {
+        SkScalar x = click->fCurr.fX;
+        SkScalar y = click->fCurr.fY;
+
+        SkScalar dx = x - click->fPrev.fX;
+        SkScalar dy = y - click->fPrev.fY;
+
+        if (fMoveLight) {

[robertphillips, 2016/08/02 16:05:07]

Rebuild the object here ...

[vjiaoblack, 2016/08/03 14:04:21]

Done.

+            fLights->light(0).setDir(SkVector3::Make( 0.12f + (200.0f - x) / 400.0f,
+                                                     -0.08f + (200.0f - y) / 400.0f, 1.0f));
+            fLights->light(1).setDir(SkVector3::Make(-0.12f + (200.0f - x) / 400.0f,
+                                                      0.12f + (200.0f - y) / 400.0f, 1.0f));
+            fLights->light(2).setDir(SkVector3::Make( 0.06f + (200.0f - x) / 400.0f,
+                                                      0.06f + (200.0f - y) / 400.0f, 1.0f));
+            fLights->light(3).setDir(SkVector3::Make(-0.06f + (200.0f - x) / 400.0f,
+                                                     -0.06f + (200.0f - y) / 400.0f, 1.0f));
+            return true;
+        }
+
+        if (click->fState == Click::State::kUp_State) {
+            fSelectedRect = -1;
+            return true;
+        }
+
+        if (fSelectedRect > -1) {
+            SkScalar x = click->fCurr.fX;
+            SkScalar y = click->fCurr.fY;
+
+            SkScalar dx = x - click->fPrev.fX;
+            SkScalar dy = y - click->fPrev.fY;
+
+            fRects[fSelectedRect].fLeft += dx;
+            fRects[fSelectedRect].fRight += dx;
+            fRects[fSelectedRect].fTop += dy;
+            fRects[fSelectedRect].fBottom += dy;
+
+            return true;
+        }
+
+        // assume last elements are highest
+        for (int i = NUM_TEST_RECTS - 1; i >= 0; i--) {
+            if (fRects[i].contains(SkRect::MakeXYWH(x, y, 1, 1))) {
+                fSelectedRect = i;
+                fRects[i].fLeft += dx;
+                fRects[i].fRight += dx;
+                fRects[i].fTop += dy;
+                fRects[i].fBottom += dy;
+
+                break;
+            }
+        }
+
+        return true;
+    }
+
+
+private:
+    sk_sp<SkLights> fLights;
+
+    typedef SampleView INHERITED;
+};
+
+
+//////////////////////////////////////////////////////////////////////////////
+static SkView* MyFactory() { return new ShadowingView; }
+static SkViewRegister reg(MyFactory);
+
+#endif