Refactor Vr activity into ChromeTabbedActivity.

chrome/browser/android/vr_shell/vr_util.cc

Index: chrome/browser/android/vr_shell/vr_util.cc
diff --git a/chrome/browser/android/vr_shell/vr_util.cc b/chrome/browser/android/vr_shell/vr_util.cc
index 69fdee8f6279dad1d138cd2cd6853f7847758aca..e3e9948f828416dd2b4a4bb45acb77c19078ba87 100644
--- a/chrome/browser/android/vr_shell/vr_util.cc
+++ b/chrome/browser/android/vr_shell/vr_util.cc
@@ -2,14 +2,107 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "chrome/browser/android/vr_shell/vr_util.h"
+
 #include <array>
 #include <cmath>
 
-#include "chrome/browser/android/vr_shell/vr_util.h"
 #include "third_party/gvr-android-sdk/src/ndk-beta/include/vr/gvr/capi/include/gvr_types.h"
 
 namespace vr_shell {
 
+// Internal matrix layout:
+//
+//   m[0][0], m[0][1], m[0][2], m[0][3],
+//   m[1][0], m[1][1], m[1][2], m[1][3],
+//   m[2][0], m[2][1], m[2][2], m[2][3],
+//   m[3][0], m[3][1], m[3][2], m[3][3],
+//
+// The translation component is in the right column m[i][3].
+//
+// The bottom row m[3][i] is (0, 0, 0, 1) for non-perspective transforms.
+//
+// These matrices are intended to be used to premultiply column vectors
+// for transforms, so successive transforms need to be left-multiplied.
+
+void setIdentityM(gvr::Mat4f& mat) {
+  float* m = (float*)mat.m;
+  for (int i = 0; i < 16; i++) {
+    m[i] = 0;
+  }
+  for (int i = 0; i < 16; i += 5) {
+    m[i] = 1.0f;
+  }
+}
+
+// Left multiply a translation matrix.
+void translateM(gvr::Mat4f& tmat, gvr::Mat4f& mat, float x, float y, float z) {
+  if (&tmat != &mat) {
+    for (int i = 0; i < 4; ++i) {
+      for (int j = 0; j < 4; ++j) {
+        tmat.m[i][j] = mat.m[i][j];
+      }
+    }
+  }
+  tmat.m[0][3] += x;
+  tmat.m[1][3] += y;
+  tmat.m[2][3] += z;
+}
+
+// Right multiply a translation matrix.
+void translateMRight(gvr::Mat4f& tmat,
+                     gvr::Mat4f& mat,
+                     float x,
+                     float y,
+                     float z) {
+  if (&tmat != &mat) {
+    for (int i = 0; i < 4; ++i) {
+      for (int j = 0; j < 3; ++j) {
+        tmat.m[i][j] = mat.m[i][j];
+      }
+    }
+  }
+
+  for (int i = 0; i < 4; i++) {
+    tmat.m[i][3] =
+        mat.m[i][0] * x + mat.m[i][1] * y + mat.m[i][2] * z + mat.m[i][3];
+  }
+}
+
+// Left multiply a scale matrix.
+void scaleM(gvr::Mat4f& tmat, gvr::Mat4f& mat, float x, float y, float z) {
+  if (&tmat != &mat) {
+    for (int i = 0; i < 4; ++i) {
+      for (int j = 0; j < 3; ++j) {
+        tmat.m[i][j] = mat.m[i][j];
+      }
+    }
+  }
+  // Multiply all rows including translation components.
+  for (int j = 0; j < 4; ++j) {
+    tmat.m[0][j] *= x;
+    tmat.m[1][j] *= y;
+    tmat.m[2][j] *= z;
+  }
+}
+
+// Right multiply a scale matrix.
+void scaleMRight(gvr::Mat4f& tmat, gvr::Mat4f& mat, float x, float y, float z) {
+  if (&tmat != &mat) {
+    for (int i = 0; i < 4; ++i) {
+      for (int j = 0; j < 3; ++j) {
+        tmat.m[i][j] = mat.m[i][j];
+      }
+    }
+  }
+  // Multiply columns, don't change translation components.
+  for (int i = 0; i < 3; ++i) {
+    tmat.m[i][0] *= x;
+    tmat.m[i][1] *= y;
+    tmat.m[i][2] *= z;
+  }
+}
+
 std::array<float, 16> MatrixToGLArray(const gvr::Mat4f& matrix) {
   // Note that this performs a *transpose* to a column-major matrix array, as
   // expected by GL. The input matrix has translation components at [i][3] for
@@ -34,6 +127,51 @@ gvr::Mat4f MatrixTranspose(const gvr::Mat4f& mat) {
   return result;
 }
 
+std::array<float, 4> MatrixVectorMul(const gvr::Mat4f& matrix,
+                                     const std::array<float, 4>& vec) {
+  std::array<float, 4> result;
+  for (int i = 0; i < 4; ++i) {
+    result[i] = 0;
+    for (int k = 0; k < 4; ++k) {
+      result[i] += matrix.m[i][k] * vec[k];
+    }
+  }
+  return result;
+}
+
+std::array<float, 3> MatrixVectorMul(const gvr::Mat4f& matrix,
+                                     const std::array<float, 3>& vec) {
+  // Use homogeneous coordinates for the multiplication.
+  std::array<float, 4> vec_h = {{vec[0], vec[1], vec[2], 1.0f}};
+  std::array<float, 4> result;
+  for (int i = 0; i < 4; ++i) {
+    result[i] = 0;
+    for (int k = 0; k < 4; ++k) {
+      result[i] += matrix.m[i][k] * vec_h[k];
+    }
+  }
+  // Convert back from homogeneous coordinates.
+  float rw = 1.0f / result[3];
+  return {{rw * result[0], rw * result[1], rw * result[2]}};
+}
+
+gvr::Vec3f MatrixVectorMul(const gvr::Mat4f& m, gvr::Vec3f v) {
+  gvr::Vec3f res;
+  res.x = m.m[0][0] * v.x + m.m[0][1] * v.y + m.m[0][2] * v.z + m.m[0][3];
+  res.y = m.m[1][0] * v.x + m.m[1][1] * v.y + m.m[1][2] * v.z + m.m[1][3];
+  res.z = m.m[2][0] * v.x + m.m[2][1] * v.y + m.m[2][2] * v.z + m.m[2][3];
+  return res;
+}
+
+// Rotation only, ignore translation components.
+gvr::Vec3f MatrixVectorRotate(const gvr::Mat4f& m, gvr::Vec3f v) {
+  gvr::Vec3f res;
+  res.x = m.m[0][0] * v.x + m.m[0][1] * v.y + m.m[0][2] * v.z;
+  res.y = m.m[1][0] * v.x + m.m[1][1] * v.y + m.m[1][2] * v.z;
+  res.z = m.m[2][0] * v.x + m.m[2][1] * v.y + m.m[2][2] * v.z;
+  return res;
+}
+
 gvr::Mat4f MatrixMul(const gvr::Mat4f& matrix1, const gvr::Mat4f& matrix2) {
   gvr::Mat4f result;
   for (int i = 0; i < 4; ++i) {
@@ -47,6 +185,129 @@ gvr::Mat4f MatrixMul(const gvr::Mat4f& matrix1, const gvr::Mat4f& matrix2) {
   return result;
 }
 
+gvr::Mat4f invertM(gvr::Mat4f mat) {
+  gvr::Mat4f resm;
+  float* result = (float*)resm.m;
+  float* m = (float*)mat.m;
+  // Invert a 4 x 4 matrix using Cramer's Rule
+
+  // transpose matrix
+  const float src0 = m[0];
+  const float src4 = m[1];
+  const float src8 = m[2];
+  const float src12 = m[3];
+
+  const float src1 = m[4];
+  const float src5 = m[5];
+  const float src9 = m[6];
+  const float src13 = m[7];
+
+  const float src2 = m[8];
+  const float src6 = m[9];
+  const float src10 = m[10];
+  const float src14 = m[11];
+
+  const float src3 = m[12];
+  const float src7 = m[13];
+  const float src11 = m[14];
+  const float src15 = m[15];
+
+  // calculate pairs for first 8 elements (cofactors)
+  const float atmp0 = src10 * src15;
+  const float atmp1 = src11 * src14;
+  const float atmp2 = src9 * src15;
+  const float atmp3 = src11 * src13;
+  const float atmp4 = src9 * src14;
+  const float atmp5 = src10 * src13;
+  const float atmp6 = src8 * src15;
+  const float atmp7 = src11 * src12;
+  const float atmp8 = src8 * src14;
+  const float atmp9 = src10 * src12;
+  const float atmp10 = src8 * src13;
+  const float atmp11 = src9 * src12;
+
+  // calculate first 8 elements (cofactors)
+  const float dst0 = (atmp0 * src5 + atmp3 * src6 + atmp4 * src7) -
+                     (atmp1 * src5 + atmp2 * src6 + atmp5 * src7);
+  const float dst1 = (atmp1 * src4 + atmp6 * src6 + atmp9 * src7) -
+                     (atmp0 * src4 + atmp7 * src6 + atmp8 * src7);
+  const float dst2 = (atmp2 * src4 + atmp7 * src5 + atmp10 * src7) -
+                     (atmp3 * src4 + atmp6 * src5 + atmp11 * src7);
+  const float dst3 = (atmp5 * src4 + atmp8 * src5 + atmp11 * src6) -
+                     (atmp4 * src4 + atmp9 * src5 + atmp10 * src6);
+  const float dst4 = (atmp1 * src1 + atmp2 * src2 + atmp5 * src3) -
+                     (atmp0 * src1 + atmp3 * src2 + atmp4 * src3);
+  const float dst5 = (atmp0 * src0 + atmp7 * src2 + atmp8 * src3) -
+                     (atmp1 * src0 + atmp6 * src2 + atmp9 * src3);
+  const float dst6 = (atmp3 * src0 + atmp6 * src1 + atmp11 * src3) -
+                     (atmp2 * src0 + atmp7 * src1 + atmp10 * src3);
+  const float dst7 = (atmp4 * src0 + atmp9 * src1 + atmp10 * src2) -
+                     (atmp5 * src0 + atmp8 * src1 + atmp11 * src2);
+
+  // calculate pairs for second 8 elements (cofactors)
+  const float btmp0 = src2 * src7;
+  const float btmp1 = src3 * src6;
+  const float btmp2 = src1 * src7;
+  const float btmp3 = src3 * src5;
+  const float btmp4 = src1 * src6;
+  const float btmp5 = src2 * src5;
+  const float btmp6 = src0 * src7;
+  const float btmp7 = src3 * src4;
+  const float btmp8 = src0 * src6;
+  const float btmp9 = src2 * src4;
+  const float btmp10 = src0 * src5;
+  const float btmp11 = src1 * src4;
+
+  // calculate second 8 elements (cofactors)
+  const float dst8 = (btmp0 * src13 + btmp3 * src14 + btmp4 * src15) -
+                     (btmp1 * src13 + btmp2 * src14 + btmp5 * src15);
+  const float dst9 = (btmp1 * src12 + btmp6 * src14 + btmp9 * src15) -
+                     (btmp0 * src12 + btmp7 * src14 + btmp8 * src15);
+  const float dst10 = (btmp2 * src12 + btmp7 * src13 + btmp10 * src15) -
+                      (btmp3 * src12 + btmp6 * src13 + btmp11 * src15);
+  const float dst11 = (btmp5 * src12 + btmp8 * src13 + btmp11 * src14) -
+                      (btmp4 * src12 + btmp9 * src13 + btmp10 * src14);
+  const float dst12 = (btmp2 * src10 + btmp5 * src11 + btmp1 * src9) -
+                      (btmp4 * src11 + btmp0 * src9 + btmp3 * src10);
+  const float dst13 = (btmp8 * src11 + btmp0 * src8 + btmp7 * src10) -
+                      (btmp6 * src10 + btmp9 * src11 + btmp1 * src8);
+  const float dst14 = (btmp6 * src9 + btmp11 * src11 + btmp3 * src8) -
+                      (btmp10 * src11 + btmp2 * src8 + btmp7 * src9);
+  const float dst15 = (btmp10 * src10 + btmp4 * src8 + btmp9 * src9) -
+                      (btmp8 * src9 + btmp11 * src10 + btmp5 * src8);
+
+  // calculate determinant
+  float det = src0 * dst0 + src1 * dst1 + src2 * dst2 + src3 * dst3;
+
+  if (det == 0.0f) {
+    det = 1E-20;
+  }
+
+  // calculate matrix inverse
+  const float invdet = 1.0f / det;
+  result[0] = dst0 * invdet;
+  result[1] = dst1 * invdet;
+  result[2] = dst2 * invdet;
+  result[3] = dst3 * invdet;
+
+  result[4] = dst4 * invdet;
+  result[5] = dst5 * invdet;
+  result[6] = dst6 * invdet;
+  result[7] = dst7 * invdet;
+
+  result[8] = dst8 * invdet;
+  result[9] = dst9 * invdet;
+  result[10] = dst10 * invdet;
+  result[11] = dst11 * invdet;
+
+  result[12] = dst12 * invdet;
+  result[13] = dst13 * invdet;
+  result[14] = dst14 * invdet;
+  result[15] = dst15 * invdet;
+
+  return resm;
+}
+
 gvr::Mat4f PerspectiveMatrixFromView(const gvr::Rectf& fov,
                                      float z_near,
                                      float z_far) {
@@ -98,6 +359,39 @@ gvr::Recti CalculatePixelSpaceRect(const gvr::Sizei& texture_size,
   return result;
 }
 
+/**
+  * Provides the direction the head is looking towards as a 3x1 unit vector.
+  * </p><p>
+  * Note that in OpenGL the forward vector points into the -Z direction.
+  * Make sure to invert it if ever used to compute the basis of a right-handed
+  * system.
+  *
+  */
+gvr::Vec3f getForwardVector(gvr::Mat4f matrix) {
+  gvr::Vec3f forward;
+  float* fp = &forward.x;
+  // Same as multiplying the inverse of the rotation component of the matrix by
+  // (0, 0, -1, 0).
+  for (int i = 0; i < 3; ++i) {
+    fp[i] = -matrix.m[2][i];
+  }
+  return forward;
+}
+
+/**
+ * Provides the relative translation of the head as a 3x1 vector.
+ *
+ */
+gvr::Vec3f getTranslation(gvr::Mat4f matrix) {
+  gvr::Vec3f translation;
+  float* tp = &translation.x;
+  // Same as multiplying the matrix by (0, 0, 0, 1).
+  for (int i = 0; i < 3; ++i) {
+    tp[i] = matrix.m[i][3];
+  }
+  return translation;
+}
+
 GLuint CompileShader(GLenum shader_type,
                      const GLchar* shader_source,
                      std::string& error) {
@@ -115,7 +409,7 @@ GLuint CompileShader(GLenum shader_type,
       GLint info_log_length;
       glGetShaderiv(shader_handle, GL_INFO_LOG_LENGTH, &info_log_length);
       GLchar* str_info_log = new GLchar[info_log_length + 1];
-      glGetShaderInfoLog(shader_handle, info_log_length, NULL, str_info_log);
+      glGetShaderInfoLog(shader_handle, info_log_length, nullptr, str_info_log);
       error = "Error compiling shader: ";
       error += str_info_log;
       delete[] str_info_log;
@@ -163,7 +457,8 @@ GLuint CreateAndLinkProgram(GLuint vertext_shader_handle,
       glGetProgramiv(program_handle, GL_INFO_LOG_LENGTH, &info_log_length);
 
       GLchar* str_info_log = new GLchar[info_log_length + 1];
-      glGetProgramInfoLog(program_handle, info_log_length, NULL, str_info_log);
+      glGetProgramInfoLog(program_handle, info_log_length, nullptr,
+                          str_info_log);
       error = "Error compiling program: ";
       error += str_info_log;
       delete[] str_info_log;
@@ -175,4 +470,78 @@ GLuint CreateAndLinkProgram(GLuint vertext_shader_handle,
   return program_handle;
 }
 
+float VectorLength(const gvr::Vec3f& vec) {
+  return sqrt(vec.x * vec.x + vec.y * vec.y + vec.z * vec.z);
+}
+
+void NormalizeVector(gvr::Vec3f& vec) {
+  float len = VectorLength(vec);
+  vec.x /= len;
+  vec.y /= len;
+  vec.z /= len;
+}
+
+float VectorDot(gvr::Vec3f& a, gvr::Vec3f& b) {
+  return a.x * b.x + a.y * b.y + a.z * b.z;
+}
+
+void NormalizeQuat(gvr::Quatf& quat) {
+  float len = sqrt(quat.qx * quat.qx + quat.qy * quat.qy + quat.qz * quat.qz +
+                   quat.qw * quat.qw);
+  quat.qx /= len;
+  quat.qy /= len;
+  quat.qz /= len;
+  quat.qw /= len;
+}
+
+gvr::Quatf QuatFromAxisAngle(float x, float y, float z, float angle) {
+  gvr::Quatf res;
+  float s = sin(angle / 2);
+  res.qx = x * s;
+  res.qy = y * s;
+  res.qz = z * s;
+  res.qw = cos(angle / 2);
+  return res;
+}
+
+gvr::Quatf QuatMultiply(const gvr::Quatf& a, const gvr::Quatf& b) {
+  gvr::Quatf res;
+  res.qw = a.qw * b.qw - a.qx * b.qx - a.qy * b.qy - a.qz * b.qz;
+  res.qx = a.qw * b.qx + a.qx * b.qw + a.qy * b.qz - a.qz * b.qy;
+  res.qy = a.qw * b.qy - a.qx * b.qz + a.qy * b.qw + a.qz * b.qx;
+  res.qz = a.qw * b.qz + a.qx * b.qy - a.qy * b.qx + a.qz * b.qw;
+  return res;
+}
+
+gvr::Mat4f QuatToMatrix(const gvr::Quatf& quat) {
+  //  const float x = quat.qx;
+  const float x2 = quat.qx * quat.qx;
+  //  const float y = quat.qy;
+  const float y2 = quat.qy * quat.qy;
+  //  const float z = quat.qz;
+  const float z2 = quat.qz * quat.qz;
+  //  const float w = quat.qw;
+  const float xy = quat.qx * quat.qy;
+  const float xz = quat.qx * quat.qz;
+  const float xw = quat.qx * quat.qw;
+  const float yz = quat.qy * quat.qz;
+  const float yw = quat.qy * quat.qw;
+  const float zw = quat.qz * quat.qw;
+
+  const float m11 = 1.0f - 2.0f * y2 - 2.0f * z2;
+  const float m12 = 2.0f * (xy - zw);
+  const float m13 = 2.0f * (xz + yw);
+  const float m21 = 2.0f * (xy + zw);
+  const float m22 = 1.0f - 2.0f * x2 - 2.0f * z2;
+  const float m23 = 2.0f * (yz - xw);
+  const float m31 = 2.0f * (xz - yw);
+  const float m32 = 2.0f * (yz + xw);
+  const float m33 = 1.0f - 2.0f * x2 - 2.0f * y2;
+
+  float ret[16] = {m11, m12, m13, 0.0f, m21,  m22,  m23,  0.0f,
+                   m31, m32, m33, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f};
+
+  return *((gvr::Mat4f*)&ret);
+}
+
 }  // namespace vr_shell