1 files changed, 80 insertions, 0 deletions
diff --git a/src/camera.c b/src/camera.c
new file mode 100644
index 0000000..f087d83
--- /dev/null
+++ b/src/camera.c
@@ -0,0 +1,80 @@
+#include "camera.h"
+static void cameraUpdateVectors(struct Camera *camera);
+
+Mat4
+cameraGetViewMatrix(struct Camera camera)
+{
+    Vec3 target = linearVec3Add(camera.position, camera.front);
+    return linearLookAt(camera.position, target, camera.up);
+}
+
+void
+cameraProcessKeyboard(
+    struct Camera *camera,
+    enum CameraMovement direction,
+    float deltaTime)
+{
+    float speed = camera->movementSpeed * deltaTime;
+    Vec3 tmp;
+
+    switch (direction) {
+        case CAMDIR_FORWARD:
+            // pos = pos + front * speed
+            tmp = linearVec3ScalarMulp(camera->front, speed);
+            camera->position = linearVec3Add(camera->position, tmp);
+            break;
+
+        case CAMDIR_BACKWARD:
+            // pos = pos + front * (-speed)
+            tmp = linearVec3ScalarMulp(camera->front, -speed);
+            camera->position = linearVec3Add(camera->position, tmp);
+            break;
+
+        case CAMDIR_LEFT:
+            // pos = pos + unit|(up x front)| * (speed)
+            tmp = linearVec3CrossProduct(camera->front, camera->up);
+            tmp = linearVec3Normalize(tmp);
+            tmp = linearVec3ScalarMulp(tmp, -speed);
+            camera->position = linearVec3Add(camera->position, tmp);
+            break;
+
+        case CAMDIR_RIGHT:
+            // pos = pos + unit|(up x front)| * (-speed)
+            tmp = linearVec3CrossProduct(camera->front, camera->up);
+            tmp = linearVec3Normalize(tmp);
+            tmp = linearVec3ScalarMulp(tmp, speed);
+            camera->position = linearVec3Add(camera->position, tmp);
+            break;
+
+        default:
+            break;
+    }
+}
+
+void
+cameraProcessMouseMovement(struct Camera *camera, float xoffset, float yoffset)
+{
+    camera->yaw += camera->mouseSensivity * xoffset;
+    camera->pitch += camera->mouseSensivity * yoffset;
+
+    if (camera->pitch > 89.0f)
+        camera->pitch = 89.0f;
+    else if (camera->pitch < -89.0f)
+        camera->pitch = - 89.0f;
+    cameraUpdateVectors(camera);
+}
+
+void
+cameraUpdateVectors(struct Camera *camera)
+{
+    Vec3 tmp;
+    float rpitch = M_PI / 180 * camera->pitch;
+    float ryaw = M_PI / 180 * camera->yaw;
+
+    tmp = linearVec3(
+            cosf(ryaw) * cosf(-rpitch),
+            sinf(-rpitch),
+            sinf(ryaw) * cosf(-rpitch));
+    camera->front = linearVec3Normalize(tmp);
+
+}