1 files changed, 137 insertions, 0 deletions
diff --git a/src/camera.c b/src/camera.c
new file mode 100644
index 0000000..44f480d
--- /dev/null
+++ b/src/camera.c
@@ -0,0 +1,137 @@
+#include "camera.h"
+
+void honey_camera_new(honey_camera* camera,
+                      vec3 position,
+                      vec3 angle,
+                      enum honey_camera_projection projection_type,
+                      float aspect_ratio,
+                      float near, float far,
+                      float fov,
+                      float left, float right, float top, float bottom) {
+  glm_vec3_copy(position, camera->position);
+  glm_vec3_copy(angle, camera->angle);
+
+  camera->projection_type = projection_type;
+
+  camera->aspect_ratio = aspect_ratio;
+  camera->near = near;
+  camera->far = far;
+  
+  if (projection_type == HONEY_PERSPECTIVE) {
+    camera->fov = fov;
+  }
+  else if (projection_type == HONEY_ORTHOGRAPHIC) {
+    camera->ortho_left = left;
+    camera->ortho_right = right;
+    camera->ortho_top = top;
+    camera->ortho_bottom = bottom;
+  }
+
+  honey_camera_calculate_view(camera);
+  honey_camera_calculate_projection(camera);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_new_perspective(honey_camera* camera,
+                                  vec3 position,
+                                  vec3 angle,
+                                  float aspect_ratio,
+                                  float near, float far,
+                                  float fov) {
+  honey_camera_new(camera,
+                   position, angle,
+                   HONEY_PERSPECTIVE,
+                   aspect_ratio, near, far, fov,
+                   0, 0, 0, 0);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_new_orthographic(honey_camera* camera,
+                                   vec3 position,
+                                   vec3 angle,
+                                   float near, float far,
+                                   float left, float right, float top, float bottom) {
+  honey_camera_new(camera,
+                   position, angle,
+                   HONEY_ORTHOGRAPHIC,
+                   0,
+                   near, far,
+                   0,
+                   left, right, top, bottom);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_calculate_look_direction(honey_camera* camera) {
+  float pitch = camera->angle[0];
+  float yaw = camera->angle[1];
+
+  float x = cos(pitch) * cos(yaw);
+  float y = sin(pitch);
+  float z = cos(pitch) * sin(yaw);
+
+  camera->look_direction[0] = x;
+  camera->look_direction[1] = y;
+  camera->look_direction[2] = z;
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_calculate_up(honey_camera* camera) {
+ float pitch = camera->angle[0];
+ float yaw = camera->angle[1];
+ float roll = camera->angle[2];
+
+ camera->up[0] = 0;
+ camera->up[1] = 1;
+ camera->up[2] = 0;
+
+ mat3 rot3;
+ mat4 rot4;
+ glm_mat4_identity(rot4);
+ glm_rotate(rot4, roll, camera->look_direction);
+ glm_mat4_pick3(rot4, rot3);
+
+ glm_mat3_mulv(rot3, camera->up, camera->up);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_calculate_right(honey_camera* camera) {
+  glm_vec3_cross(camera->up, camera->look_direction, camera->right);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_calculate_view(honey_camera* camera) {
+  honey_camera_calculate_look_direction(camera);
+  honey_camera_calculate_up(camera);
+  honey_camera_calculate_right(camera);
+
+  glm_look(camera->position, camera->look_direction, camera->up, camera->view);
+}
+
+/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
+
+void honey_camera_calculate_projection(honey_camera* camera) {
+  if (camera->projection_type == HONEY_PERSPECTIVE) {
+    glm_mat4_identity(camera->projection);
+    glm_perspective(camera->fov,
+                    camera->aspect_ratio,
+                    camera->near,
+                    camera->far,
+                    camera->projection);
+  }
+  else if (camera->projection_type == HONEY_ORTHOGRAPHIC) {
+    glm_mat4_identity(camera->projection);
+    glm_ortho(camera->ortho_left,
+              camera->ortho_right,
+              camera->ortho_bottom,
+              camera->ortho_top,
+              camera->near,
+              camera->far,
+              camera->projection);
+  }
+}