3d

Bug: skia:
Change-Id: I10e56f08a2463fcac2b7813d43d0aae35268ac27
Reviewed-on: https://skia-review.googlesource.com/130842
Commit-Queue: Brian Salomon <bsalomon@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

5 files changed, 232 insertions, 0 deletions

diff --git a/gm/3dgm.cpp b/gm/3dgm.cpp
new file mode 100644
index 0000000000..37830ae878
--- /dev/null
+++ b/gm/3dgm.cpp
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2018 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 "Sk3D.h"
+#include "SkPath.h"
+#include "SkPoint3.h"
+
+class GM3d : public skiagm::GM {
+    float   fNear = 0.5;
+    float   fFar = 4;
+    float   fAngle = SK_ScalarPI / 4;
+
+    SkPoint3    fEye { 0, 0, 4 };
+    SkPoint3    fCOA {0,0,0};//{ 0.5f, 0.5f, 0.5f };
+    SkPoint3    fUp  { 0, 1, 0 };
+
+    SkMatrix44  fMV;
+
+    SkPoint3    fP3[8];
+public:
+    GM3d() : fMV(SkMatrix44::kIdentity_Constructor) {}
+    ~GM3d() override {}
+
+protected:
+    void onOnceBeforeDraw() override {
+        int index = 0;
+        for (float x = 0; x <= 1; ++x) {
+            for (float y = 0; y <= 1; ++y) {
+                for (float z = 0; z <= 1; ++z) {
+                    fP3[index++] = { x, y, z };
+                }
+            }
+        }
+        fMV.setIdentity();
+    }
+
+    static void draw_viewport(SkCanvas* canvas, const SkMatrix& viewport) {
+        SkPaint p;
+        p.setColor(0x10FF0000);
+
+        canvas->save();
+        canvas->concat(viewport);
+        canvas->drawRect({-1, -1, 1, 1}, p);
+
+        p.setColor(0x80FF0000);
+        canvas->drawLine({-1, -1}, {1, 1}, p);
+        canvas->drawLine({1, -1}, {-1, 1}, p);
+        canvas->restore();
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        SkMatrix44  camera(SkMatrix44::kIdentity_Constructor),
+                    perspective(SkMatrix44::kIdentity_Constructor),
+                    mv = fMV;
+        SkMatrix    viewport;
+
+        {
+            float w = this->width();
+            float h = this->height();
+            float s = std::min(w, h);
+            viewport.setTranslate(1, -1);
+            viewport.postScale(s/2, -s/2);
+
+            draw_viewport(canvas, viewport);
+        }
+
+        Sk3Perspective(&perspective, fNear, fFar, fAngle);
+        Sk3LookAt(&camera, fEye, fCOA, fUp);
+        mv.postConcat(camera);
+        mv.postConcat(perspective);
+        SkPoint pts[8];
+        Sk3MapPts(pts, mv, fP3, 8);
+        viewport.mapPoints(pts, 8);
+
+        SkPaint paint;
+        paint.setStyle(SkPaint::kStroke_Style);
+
+        SkPath cube;
+
+        cube.moveTo(pts[0]);
+        cube.lineTo(pts[2]);
+        cube.lineTo(pts[6]);
+        cube.lineTo(pts[4]);
+        cube.close();
+
+        cube.moveTo(pts[1]);
+        cube.lineTo(pts[3]);
+        cube.lineTo(pts[7]);
+        cube.lineTo(pts[5]);
+        cube.close();
+
+        cube.moveTo(pts[0]);    cube.lineTo(pts[1]);
+        cube.moveTo(pts[2]);    cube.lineTo(pts[3]);
+        cube.moveTo(pts[4]);    cube.lineTo(pts[5]);
+        cube.moveTo(pts[6]);    cube.lineTo(pts[7]);
+
+        canvas->drawPath(cube, paint);
+
+        {
+            SkPoint3 src[4] = {
+                { 0, 0, 0 }, { 2, 0, 0 }, { 0, 2, 0 }, { 0, 0, 2 },
+            };
+            SkPoint dst[4];
+            mv.setConcat(perspective, camera);
+            Sk3MapPts(dst, mv, src, 4);
+            viewport.mapPoints(dst, 4);
+            const char str[] = "XYZ";
+            for (int i = 1; i <= 3; ++i) {
+                canvas->drawLine(dst[0], dst[i], paint);
+            }
+
+            for (int i = 1; i <= 3; ++i) {
+                canvas->drawText(&str[i-1], 1, dst[i].fX, dst[i].fY, paint);
+            }
+        }
+    }
+
+    SkISize onISize() override { return { 1024, 768 }; }
+
+    SkString onShortName() override { return SkString("3dgm"); }
+
+    bool onAnimate(const SkAnimTimer&) override { return false; }
+    bool onHandleKey(SkUnichar uni) override {
+        switch (uni) {
+            case 'a': fEye.fX += 0.125f; return true;
+            case 'd': fEye.fX -= 0.125f; return true;
+            case 'w': fEye.fY += 0.125f; return true;
+            case 's': fEye.fY -= 0.125f; return true;
+            case 'q': fEye.fZ += 0.125f; return true;
+            case 'z': fEye.fZ -= 0.125f; return true;
+            default: break;
+        }
+        return false;
+    }
+
+    bool onGetControls(SkMetaData*) override { return false; }
+    void onSetControls(const SkMetaData&) override {
+
+    }
+};
+
+DEF_GM(return new GM3d;)
diff --git a/gn/gm.gni b/gn/gm.gni
index d978e9d216..a4074c29ec 100644
--- a/gn/gm.gni
+++ b/gn/gm.gni
@@ -7,6 +7,7 @@
 _gm = get_path_info("../gm", "abspath")
 
 gm_sources = [
+  "$_gm/3dgm.cpp",
   "$_gm/aaa.cpp",
   "$_gm/aaclip.cpp",
   "$_gm/aarectmodes.cpp",
diff --git a/gn/utils.gni b/gn/utils.gni
index 01d31364d5..ff8f60a56c 100644
--- a/gn/utils.gni
+++ b/gn/utils.gni
@@ -22,6 +22,7 @@ skia_utils_sources = [
   "$_include/utils/SkRandom.h",
   "$_include/utils/SkShadowUtils.h",
 
+  "$_src/utils/Sk3D.cpp",
   "$_src/utils/SkBase64.cpp",
   "$_src/utils/SkBase64.h",
   "$_src/utils/SkBitSet.h",
diff --git a/src/utils/Sk3D.cpp b/src/utils/Sk3D.cpp
new file mode 100644
index 0000000000..b1b5d6c0ea
--- /dev/null
+++ b/src/utils/Sk3D.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Sk3D.h"
+
+static void set_col(SkMatrix44* m, int col, const SkPoint3& v) {
+    m->set(0, col, v.fX);
+    m->set(1, col, v.fY);
+    m->set(2, col, v.fZ);
+}
+
+static SkPoint3 cross(const SkPoint3& a, const SkPoint3& b) {
+    return {
+        a.fY * b.fZ - a.fZ * b.fY,
+        a.fZ * b.fX - a.fX * b.fZ,
+        a.fX * b.fY - a.fY * b.fX,
+    };
+}
+
+void Sk3LookAt(SkMatrix44* dst, const SkPoint3& eye, const SkPoint3& center, const SkPoint3& up) {
+    SkPoint3 f = center - eye;
+    f.normalize();
+    SkPoint3 u = up;
+    u.normalize();
+    SkPoint3 s = cross(f, u);
+    s.normalize();
+    u = cross(s, f);
+
+    dst->setIdentity();
+    set_col(dst, 0, s);
+    set_col(dst, 1, u);
+    set_col(dst, 2, -f);
+    set_col(dst, 3, eye);
+    dst->invert(dst);
+}
+
+bool Sk3Perspective(SkMatrix44* dst, float near, float far, float angle) {
+    SkASSERT(far > near);
+
+    float denomInv = sk_ieee_float_divide(1, far - near);
+    float halfAngle = angle * 0.5f;
+    float cot = sk_float_cos(halfAngle) / sk_float_sin(halfAngle);
+
+    dst->setIdentity();
+    dst->set(0, 0, cot);
+    dst->set(1, 1, cot);
+    dst->set(2, 2, (far + near) * denomInv);
+    dst->set(2, 3, 2 * far * near * denomInv);
+    dst->set(3, 2, -1);
+    return true;
+}
+
+void Sk3MapPts(SkPoint dst[], const SkMatrix44& m4, const SkPoint3 src[], int count) {
+    for (int i = 0; i < count; ++i) {
+        SkVector4 v = m4 * SkVector4{ src[i].fX, src[i].fY, src[i].fZ, 1 };
+        // clip v;
+        dst[i] = { v.fData[0] / v.fData[3], v.fData[1] / v.fData[3] };
+    }
+}
+
diff --git a/src/utils/Sk3D.h b/src/utils/Sk3D.h
new file mode 100644
index 0000000000..46bb5cce80
--- /dev/null
+++ b/src/utils/Sk3D.h
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef Sk3D_DEFINED
+#define Sk3D_DEFINED
+
+#include "SkPoint3.h"
+#include "SkMatrix44.h"
+
+void Sk3LookAt(SkMatrix44* dst, const SkPoint3& eye, const SkPoint3& center, const SkPoint3& up);
+bool Sk3Perspective(SkMatrix44* dst, float near, float far, float angle);
+void Sk3MapPts(SkPoint dst[], const SkMatrix44& m4, const SkPoint3 src[], int count);
+
+#endif
+