headtracking from joystick input

headtrack.cpp

@@ -0,0 +1,63 @@
+#include "stdafx.h"
+#include "headtrack.h"
+#include "Globals.h"
+
+headtrack::headtrack()
+{
+
+}
+
+void headtrack::find_joy() {
+    for (size_t i = GLFW_JOYSTICK_1; i <= GLFW_JOYSTICK_LAST; i++) {
+        if (!glfwJoystickPresent(i))
+            continue;
+
+        std::string name(glfwGetJoystickName(i));
+        if (name == Global.headtrack_conf.joy) {
+            joy_id = i;
+            return;
+        }
+    }
+
+    joy_id = -1;
+}
+
+float headtrack::get_axis(const float *data, int count, int axis, float mul) {
+    if (axis < 0)
+        return 0.0f;
+    if (axis >= count)
+        return 0.0f;
+
+    return data[axis] * mul;
+}
+
+void headtrack::update()
+{
+    if (joy_id == -1 || !glfwJoystickPresent(joy_id)) {
+        Global.viewport_move = glm::vec3();
+        Global.viewport_rotate = glm::vec3();
+        find_joy();
+        return;
+    }
+
+    int count;
+    const float* axes = glfwGetJoystickAxes(joy_id, &count);
+
+    auto const &move_axes = Global.headtrack_conf.move_axes;
+    auto const &rot_axes = Global.headtrack_conf.rot_axes;
+    auto const &move_mul = Global.headtrack_conf.move_mul;
+    auto const &rot_mul = Global.headtrack_conf.rot_mul;
+
+    glm::vec3 move;
+    move.x = get_axis(axes, count, move_axes.x, move_mul.x);
+    move.y = get_axis(axes, count, move_axes.y, move_mul.y);
+    move.z = get_axis(axes, count, move_axes.z, move_mul.z);
+
+    glm::vec3 rotate;
+    rotate.x = get_axis(axes, count, rot_axes.x, rot_mul.x);
+    rotate.y = get_axis(axes, count, rot_axes.y, rot_mul.y);
+    rotate.z = get_axis(axes, count, rot_axes.z, rot_mul.z);
+
+    Global.viewport_move = move;
+    Global.viewport_rotate = rotate;
+}