1 files changed, 196 insertions, 0 deletions
diff --git a/src/graphics/camera.cpp b/src/graphics/camera.cpp
new file mode 100644
index 0000000..cf0277a
--- /dev/null
+++ b/src/graphics/camera.cpp
@@ -0,0 +1,196 @@
+#include "graphics/camera.h"
+
+#include <iostream>
+
+Camera::Camera()
+    : m_position(0,0,0),
+      m_pitch(0),
+      m_yaw(0),
+      m_look(0, 0, 1),
+      m_orbitPoint(0, 0, 0),
+      m_isOrbiting(false),
+      m_view(Eigen::Matrix4f::Identity()),
+      m_proj(Eigen::Matrix4f::Identity()),
+      m_viewDirty(true),
+      m_projDirty(true),
+      m_fovY(90),
+      m_aspect(1),
+      m_near(0.1f),
+      m_far(50.f),
+      m_zoom(1)
+{}
+
+// ================== Position
+
+void Camera::setPosition(const Eigen::Vector3f &position)
+{
+    m_position  = position;
+    m_viewDirty = true;
+}
+
+void Camera::move(const Eigen::Vector3f &deltaPosition)
+{
+    if (deltaPosition.squaredNorm() == 0) return;
+
+    m_position += deltaPosition;
+
+    if (m_isOrbiting) {
+        m_orbitPoint += deltaPosition;
+    }
+
+    m_viewDirty = true;
+}
+
+Eigen::Vector3f Camera::getPosition()
+{
+    return m_position;
+}
+
+// ================== Rotation
+
+void Camera::setRotation(float pitch, float yaw)
+{
+    m_pitch = pitch;
+    m_yaw   = yaw;
+    m_viewDirty = true;
+    updateLook();
+}
+
+void Camera::rotate(float deltaPitch, float deltaYaw)
+{
+    m_pitch += deltaPitch;
+    m_yaw   += deltaYaw;
+    m_pitch  = std::clamp(m_pitch, (float) -M_PI_2 + 0.01f, (float) M_PI_2 - 0.01f);
+    m_viewDirty = true;
+    updateLook();
+
+    if (m_isOrbiting) {
+        m_position = m_orbitPoint - m_look * m_zoom;
+    }
+}
+
+// ================== Position and Rotation
+
+void Camera::lookAt(const Eigen::Vector3f &eye, const Eigen::Vector3f &target)
+{
+    m_position  = eye;
+    m_look      = (target - eye).normalized();
+    m_viewDirty = true;
+    updatePitchAndYaw();
+}
+
+// ================== Orbiting
+
+void Camera::setOrbitPoint(const Eigen::Vector3f &orbitPoint)
+{
+    m_orbitPoint = orbitPoint;
+    m_viewDirty = true;
+}
+
+bool Camera::getIsOrbiting()
+{
+    return m_isOrbiting;
+}
+
+void Camera::setIsOrbiting(bool isOrbiting)
+{
+    m_isOrbiting = isOrbiting;
+    m_viewDirty = true;
+}
+
+void Camera::toggleIsOrbiting()
+{
+    m_isOrbiting = !m_isOrbiting;
+    m_viewDirty = true;
+
+    if (m_isOrbiting) {
+        m_zoom = (m_orbitPoint - m_position).norm();
+        m_look = (m_orbitPoint - m_position).normalized();
+        updatePitchAndYaw();
+    }
+}
+
+void Camera::zoom(float zoomMultiplier)
+{
+    if (!m_isOrbiting) return;
+
+    m_zoom *= zoomMultiplier;
+    m_position = m_orbitPoint - m_look * m_zoom;
+    m_viewDirty = true;
+}
+
+// ================== Important Getters
+
+const Eigen::Matrix4f &Camera::getView()
+{
+    if (m_viewDirty) {
+        Eigen::Matrix3f R;
+        Eigen::Vector3f f = m_look.normalized();
+        Eigen::Vector3f u = Eigen::Vector3f::UnitY();
+        Eigen::Vector3f s = f.cross(u).normalized();
+        u = s.cross(f);
+        R.col(0) = s;
+        R.col(1) = u;
+        R.col(2) = -f;
+        m_view.topLeftCorner<3, 3>() = R.transpose();
+        m_view.topRightCorner<3, 1>() = -R.transpose() * m_position;
+        m_view(3, 3) = 1.f;
+        m_viewDirty = false;
+    }
+    return m_view;
+}
+
+const Eigen::Matrix4f &Camera::getProjection()
+{
+    if (m_projDirty) {
+        float theta = m_fovY * 0.5f;
+        float invRange = 1.f / (m_far - m_near);
+        float invtan = 1.f / tanf(theta);
+        m_proj(0, 0) = invtan / m_aspect;
+        m_proj(1, 1) = invtan;
+        m_proj(2, 2) = -(m_near + m_far) * invRange;
+        m_proj(3, 2) = -1;
+        m_proj(2, 3) = -2 * m_near * m_far * invRange;
+        m_proj(3, 3) = 0;
+        m_projDirty = false;
+    }
+    return m_proj;
+}
+
+const Eigen::Vector3f &Camera::getLook()
+{
+    return m_look;
+}
+
+// ================== Intrinsics
+
+void Camera::setPerspective(float fovY, float aspect, float near, float far)
+{
+    m_fovY = fovY;
+    m_aspect = aspect;
+    m_near = near;
+    m_far = far;
+    m_projDirty = true;
+}
+
+void Camera::setAspect(float aspect)
+{
+    m_aspect = aspect;
+    m_projDirty = true;
+}
+
+// ================== Private Helpers
+
+void Camera::updateLook()
+{
+    m_look = Eigen::Vector3f(0, 0, 1);
+    m_look = Eigen::AngleAxis<float>(m_pitch, Eigen::Vector3f::UnitX()) * m_look;
+    m_look = Eigen::AngleAxis<float>(m_yaw,   Eigen::Vector3f::UnitY()) * m_look;
+    m_look = m_look.normalized();
+}
+
+void Camera::updatePitchAndYaw()
+{
+    m_pitch = asinf(-m_look.y());
+    m_yaw   = atan2f(m_look.x(), m_look.z());
+}