Cleanup: Add more const correctness to some functions

These are functions that are used by eevee-rewrite which has more strict
const correctness.

source/blender/blenkernel/BKE_camera.h

@@ -46,7 +46,7 @@ void *BKE_camera_add(struct Main *bmain, const char *name);
 /**
  * Get the camera's DOF value, takes the DOF object into account.
  */
-float BKE_camera_object_dof_distance(struct Object *ob);
+float BKE_camera_object_dof_distance(const struct Object *ob);
 
 int BKE_camera_sensor_fit(int sensor_fit, float sizex, float sizey);
 float BKE_camera_sensor_size(int sensor_fit, float sensor_x, float sensor_y);

source/blender/blenkernel/intern/camera.c

@@ -218,7 +218,7 @@ void *BKE_camera_add(Main *bmain, const char *name)
   return cam;
 }
 
-float BKE_camera_object_dof_distance(Object *ob)
+float BKE_camera_object_dof_distance(const Object *ob)
 {
   Camera *cam = (Camera *)ob->data;
   if (ob->type != OB_CAMERA) {

source/blender/draw/intern/DRW_render.h

@@ -293,7 +293,9 @@ DRWShaderLibrary *DRW_shader_library_create(void);
 /**
  * \warning Each library must be added after all its dependencies.
  */
-void DRW_shader_library_add_file(DRWShaderLibrary *lib, char *lib_code, const char *lib_name);
+void DRW_shader_library_add_file(DRWShaderLibrary *lib,
+                                 const char *lib_code,
+                                 const char *lib_name);
 #define DRW_SHADER_LIB_ADD(lib, lib_name) \
   DRW_shader_library_add_file(lib, datatoc_##lib_name##_glsl, STRINGIFY(lib_name) ".glsl")
 
@@ -696,7 +698,7 @@ const DRWView *DRW_view_default_get(void);
 /**
  * MUST only be called once per render and only in render mode. Sets default view.
  */
-void DRW_view_default_set(DRWView *view);
+void DRW_view_default_set(const DRWView *view);
 /**
  * \warning Only use in render AND only if you are going to set view_default again.
  */
@@ -704,7 +706,7 @@ void DRW_view_reset(void);
 /**
  * Set active view for rendering.
  */
-void DRW_view_set_active(DRWView *view);
+void DRW_view_set_active(const DRWView *view);
 const DRWView *DRW_view_get_active(void);
 
 /**

source/blender/draw/intern/draw_manager_data.c

@@ -1904,7 +1904,7 @@ void DRW_view_reset(void)
   DST.view_previous = NULL;
 }
 
-void DRW_view_default_set(DRWView *view)
+void DRW_view_default_set(const DRWView *view)
 {
   BLI_assert(DST.view_default == NULL);
   DST.view_default = view;

source/blender/draw/intern/draw_manager_exec.c

@@ -354,7 +354,7 @@ static bool draw_call_is_culled(const DRWResourceHandle *handle, DRWView *view)
   return (culling->mask & view->culling_mask) != 0;
 }
 
-void DRW_view_set_active(DRWView *view)
+void DRW_view_set_active(const DRWView *view)
 {
   DST.view_active = (view) ? view : DST.view_default;
 }

source/blender/draw/intern/draw_manager_shader.c

@@ -629,7 +629,7 @@ static uint32_t drw_shader_dependencies_get(const DRWShaderLibrary *lib, const c
   return deps;
 }
 
-void DRW_shader_library_add_file(DRWShaderLibrary *lib, char *lib_code, const char *lib_name)
+void DRW_shader_library_add_file(DRWShaderLibrary *lib, const char *lib_code, const char *lib_name)
 {
   int index = -1;
   for (int i = 0; i < MAX_LIB; i++) {

source/blender/render/RE_pipeline.h

@@ -454,12 +454,14 @@ struct RenderPass *RE_pass_find_by_type(volatile struct RenderLayer *rl,
 #define RE_BAKE_DISPLACEMENT 1
 #define RE_BAKE_AO 2
 
-void RE_GetCameraWindow(struct Render *re, struct Object *camera, float mat[4][4]);
+void RE_GetCameraWindow(struct Render *re, const struct Object *camera, float mat[4][4]);
 /**
  * Must be called after #RE_GetCameraWindow(), does not change `re->winmat`.
  */
-void RE_GetCameraWindowWithOverscan(struct Render *re, float overscan, float r_winmat[4][4]);
-void RE_GetCameraModelMatrix(struct Render *re, struct Object *camera, float r_modelmat[4][4]);
+void RE_GetCameraWindowWithOverscan(const struct Render *re, float overscan, float r_winmat[4][4]);
+void RE_GetCameraModelMatrix(const struct Render *re,
+                             const struct Object *camera,
+                             float r_modelmat[4][4]);
 
 struct Scene *RE_GetScene(struct Render *re);
 void RE_SetScene(struct Render *re, struct Scene *sce);

source/blender/render/intern/initrender.c

@@ -194,13 +194,13 @@ void RE_SetCamera(Render *re, Object *cam_ob)
   re->viewplane = params.viewplane;
 }
 
-void RE_GetCameraWindow(struct Render *re, struct Object *camera, float r_winmat[4][4])
+void RE_GetCameraWindow(struct Render *re, const struct Object *camera, float r_winmat[4][4])
 {
   RE_SetCamera(re, camera);
   copy_m4_m4(r_winmat, re->winmat);
 }
 
-void RE_GetCameraWindowWithOverscan(struct Render *re, float overscan, float r_winmat[4][4])
+void RE_GetCameraWindowWithOverscan(const struct Render *re, float overscan, float r_winmat[4][4])
 {
   CameraParams params;
   params.is_ortho = re->winmat[3][3] != 0.0f;
@@ -218,7 +218,7 @@ void RE_GetCameraWindowWithOverscan(struct Render *re, float overscan, float r_w
   copy_m4_m4(r_winmat, params.winmat);
 }
 
-void RE_GetCameraModelMatrix(Render *re, struct Object *camera, float r_modelmat[4][4])
+void RE_GetCameraModelMatrix(const Render *re, const struct Object *camera, float r_modelmat[4][4])
 {
   BKE_camera_multiview_model_matrix(&re->r, camera, re->viewname, r_modelmat);
 }