moved from h4570/tyra

src/engine/modules/camera_base.cpp

@@ -0,0 +1,80 @@
+/*
+# ______       ____   ___
+#   |     \/   ____| |___|    
+#   |     |   |   \  |   |       
+#-----------------------------------------------------------------------
+# Copyright 2020, tyra - https://github.com/h4570/tyra
+# Licenced under Apache License 2.0
+# Sandro Sobczyński <sandro.sobczynski@gmail.com>
+*/
+
+#include "../include/modules/camera_base.hpp"
+
+#include <fastmath.h>
+#include "../include/utils/debug.hpp"
+#include "../include/utils/math.hpp"
+
+// ----
+// Constructors/Destructors
+// ----
+
+/** Initializes vars and calculate width/height of near and far plane 
+ * @param fov (FOV in radians)/2
+ * @param ratio Aspect ratio
+*/
+CameraBase::CameraBase(ScreenSettings *t_screen, Vector3 *t_position, Vector3 *t_up, Vector3 *t_unitCirclePosition)
+    : screen(t_screen)
+{
+    PRINT_LOG("Initializing frustum");
+    farPlaneDist = screen->farPlaneDist;
+    nearPlaneDist = screen->nearPlaneDist;
+    float tang = tanf(screen->fov * Math::HALF_ANG2RAD);
+    nearHeight = tang * nearPlaneDist;
+    nearWidth = nearHeight * screen->aspectRatio;
+    farHeight = tang * farPlaneDist;
+    farWidth = farHeight * screen->aspectRatio;
+    position2 = t_position;
+    up2 = t_up;
+    unitCirclePosition2 = t_unitCirclePosition;
+    PRINT_LOG("CameraBase initialized!");
+}
+
+// ----
+// Methods
+// ----
+
+/** Calculates and updates frustum planes
+ * http://www.lighthouse3d.com/tutorials/view-frustum-culling/geometric-approach-extracting-the-planes/
+ */
+void CameraBase::updatePlanes(Vector3 t_target)
+{
+    Vector3 nearCenter, farCenter, X, Y, Z;
+    // compute the Z axis of camera
+    Z = *position2 - t_target;
+    Z.normalize();
+    // X axis of camera of given "up" vector and Z axis
+    X = *up2 * Z;
+    X.normalize();
+    // the real "up" vector is the cross product of Z and X
+    Y = Z * X;
+    // compute the center of the near and far planes
+    nearCenter = *position2 - Z * nearPlaneDist;
+    farCenter = *position2 - Z * farPlaneDist;
+    // compute the 8 corners of the frustum
+    ntl = nearCenter + Y * nearHeight - X * nearWidth;
+    ntr = nearCenter + Y * nearHeight + X * nearWidth;
+    nbl = nearCenter - Y * nearHeight - X * nearWidth;
+    nbr = nearCenter - Y * nearHeight + X * nearWidth;
+
+    ftl = farCenter + Y * farHeight - X * farWidth;
+    fbr = farCenter - Y * farHeight + X * farWidth;
+    ftr = farCenter + Y * farHeight + X * farWidth;
+    fbl = farCenter - Y * farHeight - X * farWidth;
+
+    planes[0].update(ntr, ntl, ftl); // Top
+    planes[1].update(nbl, nbr, fbr); // BOTTOM
+    planes[2].update(ntl, nbl, fbl); // LEFT
+    planes[3].update(nbr, ntr, fbr); // RIGHT
+    planes[4].update(ntl, ntr, nbr); // NEAR
+    planes[5].update(ftr, ftl, fbl); // FAR
+}