[Bf-blender-cvs] [cd41b9a9a4f] temp-lineart-contained: LineArt: Optimized tiling strategy for ortho and perspective cameras.

[YimingWu]

Commit: cd41b9a9a4f5ed05db389e9bf14afaecc88cfd64
Author: YimingWu
Date:   Wed Apr 14 15:05:45 2021 +0800
Branches: temp-lineart-contained
https://developer.blender.org/rBcd41b9a9a4f5ed05db389e9bf14afaecc88cfd64

LineArt: Optimized tiling strategy for ortho and perspective cameras.

===================================================================

M	source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h
M	source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c

===================================================================

diff --git a/source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h b/source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h
index 413870de28e..ae29382aac5 100644
--- a/source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h
+++ b/source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h
@@ -206,6 +206,16 @@ typedef struct LineartChainRegisterEntry {
   char is_left;
 } LineartChainRegisterEntry;
 
+enum eLineArtTileRecursiveLimit {
+  /* If tile gets this small, it's already much smaller than a pixel. No need to continue
+   * splitting. */
+  LRT_TILE_RECURSIVE_PERSPECTIVE = 30,
+  /* This is a tried-and-true safe value for high poly models that also needed ortho rendering. */
+  LRT_TILE_RECURSIVE_ORTHO = 10,
+};
+
+#define LRT_TILE_SPLITTING_TRIANGLE_LIMIT 100
+
 typedef struct LineartRenderBuffer {
   struct LineartRenderBuffer *prev, *next;
 
@@ -221,6 +231,11 @@ typedef struct LineartRenderBuffer {
   struct LineartBoundingArea *initial_bounding_areas;
   unsigned int bounding_area_count;
 
+  /* When splitting bounding areas, if there's an ortho camera placed at a straight angle, there
+   * will be a lot of triangles aligned in line which can not be separated by continue subdividing
+   * the tile. So we set a strict limit when using ortho camera. See eLineArtTileRecursiveLimit. */
+  int tile_recursive_level;
+
   ListBase vertex_buffer_pointers;
   ListBase line_buffer_pointers;
   ListBase triangle_buffer_pointers;
diff --git a/source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c b/source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c
index e3091a484ea..1e6ea18c103 100644
--- a/source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c
+++ b/source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c
@@ -2835,6 +2835,13 @@ static LineartRenderBuffer *lineart_create_render_buffer(Scene *scene,
   rb->w = scene->r.xsch;
   rb->h = scene->r.ysch;
 
+  if (rb->cam_is_persp) {
+    rb->tile_recursive_level = LRT_TILE_RECURSIVE_PERSPECTIVE;
+  }
+  else {
+    rb->tile_recursive_level = LRT_TILE_RECURSIVE_ORTHO;
+  }
+
   double asp = ((double)rb->w / (double)rb->h);
   rb->shift_x = (asp >= 1) ? c->shiftx : c->shiftx * asp;
   rb->shift_y = (asp <= 1) ? c->shifty : c->shifty * asp;
@@ -3251,7 +3258,8 @@ static void lineart_bounding_area_link_triangle(LineartRenderBuffer *rb,
      * Here we use recursive limit. This is especially useful in orthographic render,
      * where a lot of faces could easily line up perfectly in image space,
      * which can not be separated by simply slicing the image tile. */
-    if (root_ba->triangle_count > 200 && recursive && recursive_level < 10) {
+    if (root_ba->triangle_count > LRT_TILE_SPLITTING_TRIANGLE_LIMIT && recursive &&
+        recursive_level < rb->tile_recursive_level) {
       lineart_bounding_area_split(rb, root_ba, recursive_level);
     }
     if (recursive && do_intersection && rb->use_intersections) {