adding new GM to demostrate new shadows

gm/victor-shadows.cpp

+/*

[jvanverth1, 2016/07/26 15:01:24]

I'd rename this to something more generic, like shadow-maps.cpp and
ShadowMapsGM.

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+ * 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"

[robertphillips, 2016/07/26 16:15:04]

Do you still need SkDrawFilter.h ?

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+#include "SkDrawFilter.h"
+#include "SkLights.h"
+#include "SkPictureRecorder.h"
+#include "SkSurface.h"
+#include "SkPaintFilterCanvas.h"
+#include "SkMatrix.h"
+#include "SkShadowShader.h"
+#include "SkBitmapProcShader.h"
+#include "SkNormalSource.h"
+

[robertphillips, 2016/07/26 16:15:04]

overlength line
file static methods are make_shadow_shader formatted

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+static sk_sp<SkShader> makeShadowShader(sk_sp<SkImage> povDepth, sk_sp<SkImage> diffuse, sk_sp<SkLights> lights) {
+    // TODO: Victor continues to figure this out
+    SkMatrix matrix1 = SkMatrix::I();
+    SkMatrix matrix2 = SkMatrix::I();
+
+    // this is the 0, 0, 1  light

[jvanverth1, 2016/07/26 15:01:24]

It's unclear based on this comment what this means. And do you need to pass in
the povDepth image and create a separate shader for this? Can't you just create
a temporary image in the SkShadowShader?

[vjiaoblack, 2016/07/27 15:26:27]

Is that necessarily better? Asking because IDK. The shader that I copied seemed
to prefer / have no problem with using shaders / normal sources.

+    sk_sp<SkShader> povDepthShader = povDepth->makeShader(
+            SkShader::kClamp_TileMode,
+            SkShader::kClamp_TileMode,
+            &matrix1);

[jvanverth1, 2016/07/26 15:01:24]

If the matrix is identity, you don't need to pass it in. 

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+
+    sk_sp<SkShader> diffuseShader = diffuse->makeShader(
+            SkShader::kClamp_TileMode,
+            SkShader::kClamp_TileMode,
+            &matrix2);
+

[robertphillips, 2016/07/26 16:15:05]

std::move(lights) ?

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+    return SkShadowShader::Make(std::move(povDepthShader), std::move(diffuseShader), lights);
+}
+

[robertphillips, 2016/07/26 16:15:05]

If it is named this way it should be file static
// add a comment

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+sk_sp<SkPicture> make_picture(int width, int height, sk_sp<SkLights> lights) {

[jvanverth1, 2016/07/26 15:01:24]

This name seems a little generic. Maybe make_test_picture? Or include it as part
of the ShadowsGM class.

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+    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);
+
+    // TODO: Maybe add the ID here along with the depth
+
+    paint.setColor(0xFFEE8888);
+
+    canvas->translateZ(80);
+    canvas->drawRect(SkRect::MakeLTRB(200,150,350,300), paint);
+
+    paint.setColor(0xFF88EE88);
+
+    canvas->translateZ(80);
+    canvas->drawRect(SkRect::MakeLTRB(150,200,300,350), paint);
+
+    paint.setColor(0xFF8888EE);
+
+    canvas->translateZ(80);
+    canvas->drawRect(SkRect::MakeLTRB(100,100,250,250), paint);
+    // TODO: Add an assert that Z order matches painter's order
+    // TODO: think about if the Z-order always matching painting order is too strict
+
+    return recorder.finishRecordingAsPicture();
+}
+
+
+namespace skiagm {
+

[robertphillips, 2016/07/26 16:15:04]

// Why does this class exist

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+class SkShadowPaintFilterCanvas : public SkPaintFilterCanvas {
+public:
+

[robertphillips, 2016/07/26 16:15:04]

Do you need to this entry point ?
It isn't virtual in the base class.

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+    sk_sp<SkLights> getLights() {
+        return INHERITED::getLights();
+    }
+

[robertphillips, 2016/07/26 16:15:05]

Can you fit this all on one line. Also no spaces in "( canvas )".

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+    SkShadowPaintFilterCanvas(SkCanvas* canvas)
+    : SkPaintFilterCanvas( canvas ) { }
+
+    bool onFilter(SkTCopyOnFirstWrite<SkPaint>* paint, Type type) const override {
+        if (*paint) {
+            uint32_t z = this->getZ();
+            SkColor color = 0xFF000000; // init color to opaque white
+            color |= z; // Put the index into the blue component
+            paint->writable()->setColor(color);
+        }
+
+        return true;
+    }
+
+    void onDrawPicture(const SkPicture* picture, const SkMatrix* matrix, const SkPaint* paint) {

[robertphillips, 2016/07/26 16:15:04]

Maybe some words here about how the updating of the matrix works within a
picture draw ?
Particularly, nested pictures.

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+        SkTCopyOnFirstWrite<SkPaint> filteredPaint(paint);

[robertphillips, 2016/07/26 16:15:05]

Calls to member functions are preceded with "this->"
Why are we explicitly filtering here - won't the base class handle that for us?

[vjiaoblack, 2016/07/27 15:26:25]

Filtering is necessary for calling onFilter, which is necessary for rendering
depths

+        if (onFilter(&filteredPaint, kPicture_Type))

[robertphillips, 2016/07/26 16:15:04]

Need {}s around this line
Not "this->INHERITED::onDrawPicture" ?

[vjiaoblack, 2016/07/27 15:26:27]

Doing that didn't work.

+            SkCanvas::onDrawPicture(picture, matrix, filteredPaint);
+    }
+
+    void updateMatrix() {

[robertphillips, 2016/07/26 16:15:04]

this->

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+        save();
+

[robertphillips, 2016/07/26 16:15:04]

Shouldn't we only ever have one light when we get here ?

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+        // TODO which light do we set?
+        SkVector3 lightDir = this->fLights->light(0).dir();

[jvanverth1, 2016/07/26 15:01:24]

Some sort of comment here that describes what you're doing would be helpful. And
I thought you had multiple lights working? 

[vjiaoblack, 2016/07/27 15:26:25]

I did! 
I can't really pass into these override-ed functions a value to tell it what
light to render the shadow map for. Thus, I simply decided to draw the shadow
map from the first light in its fLights (inherited from SkCanvas).

We go through all the lights to render shadow maps for and take turns setting
SPFCanvas's fLights equal to them.

+        SkScalar x = lightDir.fX * this->getZ();
+        SkScalar y = lightDir.fY * this->getZ();
+
+        this->translate(x, y);
+    }
+
+    void onDrawPaint(const SkPaint& paint) {

[robertphillips, 2016/07/26 16:15:05]

this-> & all following instances too

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+        updateMatrix();
+        this->INHERITED::onDrawPaint(paint);

[robertphillips, 2016/07/26 16:15:04]

this-> & all following instances too

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+        restore();
+    }
+
+    void onDrawPoints(PointMode mode, size_t count, const SkPoint pts[],

[robertphillips, 2016/07/26 16:15:05]

align the "const SkPint& paint" somehow

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+                                           const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawPoints(mode, count, pts, paint);
+        restore();
+    }
+
+    void onDrawRect(const SkRect& rect, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawRect(rect, paint);
+        restore();
+    }
+
+    void onDrawRRect(const SkRRect& rrect, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawRRect(rrect, paint);
+        restore();
+    }
+
+    void onDrawDRRect(const SkRRect& outer, const SkRRect& inner,
+                                           const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawDRRect(outer, inner, paint);
+        restore();
+    }
+
+    void onDrawOval(const SkRect& rect, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawOval(rect, paint);
+        restore();
+    }
+
+    void onDrawPath(const SkPath& path, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawPath(path, paint);
+        restore();
+    }
+
+    void onDrawBitmap(const SkBitmap& bm, SkScalar left, SkScalar top,
+                                           const SkPaint* paint) {
+        updateMatrix();
+        this->INHERITED::onDrawBitmap(bm, left, top, paint);
+        restore();
+    }
+
+    void onDrawBitmapRect(const SkBitmap& bm, const SkRect* src, const SkRect& dst,
+                                               const SkPaint* paint, SrcRectConstraint constraint) {
+        updateMatrix();
+        this->INHERITED::onDrawBitmapRect(bm, src, dst, paint, constraint);
+        restore();
+    }
+
+    void onDrawBitmapNine(const SkBitmap& bm, const SkIRect& center,
+                                               const SkRect& dst, const SkPaint* paint) {
+        updateMatrix();
+        this->INHERITED::onDrawBitmapNine(bm, center, dst, paint);
+        restore();
+    }
+
+    void onDrawImage(const SkImage* image, SkScalar left, SkScalar top,
+                                          const SkPaint* paint) {
+        updateMatrix();
+        this->INHERITED::onDrawImage(image, left, top, paint);
+        restore();
+    }
+
+    void onDrawImageRect(const SkImage* image, const SkRect* src,
+                                              const SkRect& dst, const SkPaint* paint,
+                                              SrcRectConstraint constraint) {
+        updateMatrix();
+        this->INHERITED::onDrawImageRect(image, src, dst, paint, constraint);
+        restore();
+    }
+
+    void onDrawImageNine(const SkImage* image, const SkIRect& center,
+                                              const SkRect& dst, const SkPaint* paint) {
+        updateMatrix();
+        this->INHERITED::onDrawImageNine(image, center, dst, paint);
+        restore();
+    }
+
+    void onDrawVertices(VertexMode vmode, int vertexCount,
+                                             const SkPoint vertices[], const SkPoint texs[],
+                                             const SkColor colors[], SkXfermode* xmode,
+                                             const uint16_t indices[], int indexCount,
+                                             const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawVertices(vmode, vertexCount, vertices, texs, colors,
+                                        xmode, indices, indexCount, paint);
+        restore();
+    }
+
+    void onDrawPatch(const SkPoint cubics[], const SkColor colors[],
+                                          const SkPoint texCoords[], SkXfermode* xmode,
+                                          const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawPatch(cubics, colors, texCoords, xmode, paint);
+        restore();
+    }
+
+    void onDrawText(const void* text, size_t byteLength, SkScalar x, SkScalar y,
+                                         const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawText(text, byteLength, x, y, paint);
+        restore();
+    }
+
+    void onDrawPosText(const void* text, size_t byteLength, const SkPoint pos[],
+                                            const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawPosText(text, byteLength, pos, paint);
+        restore();
+    }
+
+    void onDrawPosTextH(const void* text, size_t byteLength, const SkScalar xpos[],
+                                             SkScalar constY, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawPosTextH(text, byteLength, xpos, constY, paint);
+        restore();
+    }
+
+    void onDrawTextOnPath(const void* text, size_t byteLength, const SkPath& path,
+                                               const SkMatrix* matrix, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawTextOnPath(text, byteLength, path, matrix, paint);
+        restore();
+    }
+
+    void onDrawTextRSXform(const void* text, size_t byteLength,
+                                                const SkRSXform xform[], const SkRect* cull,
+                                                const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawTextRSXform(text, byteLength, xform, cull, paint);
+        restore();
+    }
+
+    void onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y, const SkPaint& paint) {
+        updateMatrix();
+        this->INHERITED::onDrawTextBlob(blob, x, y, paint);
+        restore();
+    }
+
+private:
+    typedef SkPaintFilterCanvas INHERITED;
+
+};
+
+class VictorShadowsGM : public GM {
+public:
+    VictorShadowsGM() {
+
+        this->setBGColor(sk_tool_utils::color_to_565(0xFFCCCCCC));

[robertphillips, 2016/07/26 16:15:04]

move the construction of the lights into onOnceBeforeDraw ?

// Create a light set consisting of greenish infinite light pointing slightly to
the right and a reddish infinite light pointing slightly down

?

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+        SkLights::Builder builder;
+        builder.add(SkLights::Light(SkColor3f::Make(0.2f, 0.3f, 0.4f),
+                                    SkVector3::Make(0.22f, 0.12f, 0.9747f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.4f, 0.3f, 0.2f),
+                                    SkVector3::Make(0.12f, 0.22f, 0.9747f)));
+        builder.add(SkLights::Light(SkColor3f::Make(0.4f, 0.4f, 0.4f)));
+        fLights = builder.finish();
+    }
+
+protected:
+    static const int kWidth = 400;
+    static const int kHeight = 400;
+
+    SkString onShortName() override {

[robertphillips, 2016/07/26 16:15:05]

Probably rename to shadowmap-shadows or something else

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+        return SkString("victor-shadows");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(kWidth, kHeight);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        // This picture stores the picture of the scene.

[robertphillips, 2016/07/26 16:15:04]

depth maps or shadow maps ?

[vjiaoblack, 2016/07/27 15:26:26]

Technically, shadow maps === depth maps, right?
(are equivalent by definition, not sure if thats the right symb)

+        // It's used to generate the depth maps.
+        sk_sp<SkPicture> pic(make_picture(kWidth, kHeight, fLights));
+

[robertphillips, 2016/07/26 16:15:04]

Unless I'm missing something this isn't a cast. Do you mean: Wrap the input
canvas in an ShadowPaintFilterCanvas ?

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+        // The general ShadowPaintFilterCanvas cast of input canvas
+        sk_sp<SkShadowPaintFilterCanvas> SPFCanvas = sk_make_sp<SkShadowPaintFilterCanvas>(canvas);
+
+        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: compute the correct size of the shadow map from the light properties
+            // TODO: maybe add a kDepth_8_SkColorType
+            // TODO: change to kIndex_8_SkColorType

[jvanverth1, 2016/07/26 15:01:24]

Or use kAlpha_8_SkColorType?

[robertphillips, 2016/07/26 16:15:04]

We should probably avoid trying to render to Index_8. As Jim mentions, kAlpha_8
is probably the way to go.

[vjiaoblack, 2016/07/27 15:26:26]

Is that possible through SkPaint?

[vjiaoblack, 2016/07/27 15:26:27]

I don't think this is actually possible with the current way we do this.

Using the SPFCanvas means that I'm whacking the paint to get the right output
into the field. Since SkPaint only has a fColor32 (right? I tried for variance
maps to use a kRGBA_16F but it wouldn't hold due to this), any change in this
doesn't really work well, right?

+
+            SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
+                                                 kBGRA_8888_SkColorType,
+                                                 kOpaque_SkAlphaType);
+
+            sk_sp<SkSurface> surf(SPFCanvas->makeSurface(info));

[robertphillips, 2016/07/26 16:15:04]

// Wrap the new canvas in a ShadowPaintFilterCanvas

only with more semantic info ?

[vjiaoblack, 2016/07/27 15:26:25]

Done.

+            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(curLight);
+            depthMapCanvas->drawPicture(pic);
+
+            fLights->light(i).setShadowMap(surf->makeImageSnapshot());
+        }
+

[robertphillips, 2016/07/26 16:15:05]

// TODO: plumb down each primitive's Z so we don't have to separately render the
depth and color for the final pass 

?

[vjiaoblack, 2016/07/27 15:26:25]

Done.

+        sk_sp<SkImage> povDepthMap;
+        sk_sp<SkImage> diffuseMap;
+
+        // 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);
+
+            sk_sp<SkSurface> surf(SPFCanvas->makeSurface(info));

[robertphillips, 2016/07/26 16:15:04]

// Wrap ...

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+            sk_sp<SkShadowPaintFilterCanvas> depthMapCanvas =
+                    sk_make_sp<SkShadowPaintFilterCanvas>(surf->getCanvas());
+
+            // set the depth map canvas to have the light we're drawing.

[robertphillips, 2016/07/26 16:15:05]

How does curLight differ from povLight ?

[vjiaoblack, 2016/07/27 15:26:27]

Done.

+            sk_sp<SkLights> curLight = builder.finish();
+            depthMapCanvas->setLights(curLight);
+
+            depthMapCanvas->drawPicture(pic);
+
+            povDepthMap = surf->makeImageSnapshot();
+        }
+
+        // diffuseMap
+        {
+            SkImageInfo info = SkImageInfo::Make(kWidth, kHeight,
+                                                 kBGRA_8888_SkColorType,
+                                                 kOpaque_SkAlphaType);
+
+            sk_sp<SkSurface> surf(SPFCanvas->makeSurface(info));
+            surf->getCanvas()->drawPicture(pic);
+
+            diffuseMap = surf->makeImageSnapshot();
+        }
+
+        sk_sp<SkShader> shadowShader = makeShadowShader(povDepthMap, diffuseMap, fLights);
+        SkPaint paint;
+        paint.setShader(shadowShader);
+
+        canvas->drawRect(SkRect::MakeIWH(400, 400), paint);

[jvanverth1, 2016/07/26 15:01:24]

kWidth, kHeight?

[vjiaoblack, 2016/07/27 15:26:26]

Done.

+    }
+
+private:
+    sk_sp<SkLights> fLights;
+
+    typedef GM INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+DEF_GM(return new VictorShadowsGM;)
+}