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>

2 files changed, 83 insertions, 0 deletions

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
+