Image Engine: Performance 8 byte images.

Previously we used to cache a float image representation of the image in
rect_float. This adds some incorrect behavior as many areas only expect
one of these buffers to be used.

This patch stores float buffers inside the image engine. This is done per
instance. In the future we should consider making a global cache.

1 files changed, 60 insertions, 23 deletions

diff --git a/source/blender/imbuf/intern/divers.c b/source/blender/imbuf/intern/divers.c
index f23748e59a2..c4de30660e2 100644
--- a/source/blender/imbuf/intern/divers.c
+++ b/source/blender/imbuf/intern/divers.c
@@ -23,6 +23,7 @@
  */
 
 #include "BLI_math.h"
+#include "BLI_rect.h"
 #include "BLI_utildefines.h"
 
 #include "IMB_filter.h"
@@ -769,6 +770,61 @@ void IMB_rect_from_float(ImBuf *ibuf)
   ibuf->userflags &= ~IB_RECT_INVALID;
 }
 
+void IMB_float_from_rect_ex(struct ImBuf *dst,
+                            const struct ImBuf *src,
+                            const rcti *region_to_update)
+{
+  BLI_assert_msg(dst->rect_float != NULL,
+                 "Destination buffer should have a float buffer assigned.");
+  BLI_assert_msg(src->rect != NULL, "Source buffer should have a byte buffer assigned.");
+  BLI_assert_msg(dst->x == src->x, "Source and destination buffer should have the same dimension");
+  BLI_assert_msg(dst->y == src->y, "Source and destination buffer should have the same dimension");
+  BLI_assert_msg(dst->channels = 4, "Destination buffer should have 4 channels.");
+  BLI_assert_msg(region_to_update->xmin >= 0,
+                 "Region to update should be clipped to the given buffers.");
+  BLI_assert_msg(region_to_update->ymin >= 0,
+                 "Region to update should be clipped to the given buffers.");
+  BLI_assert_msg(region_to_update->xmax < dst->x,
+                 "Region to update should be clipped to the given buffers.");
+  BLI_assert_msg(region_to_update->ymax < dst->y,
+                 "Region to update should be clipped to the given buffers.");
+
+  float *rect_float = dst->rect_float;
+  rect_float += (region_to_update->xmin + region_to_update->ymin * dst->x) * 4;
+  unsigned char *rect = (unsigned char *)src->rect;
+  rect += (region_to_update->xmin + region_to_update->ymin * dst->x) * 4;
+  const int region_width = BLI_rcti_size_x(region_to_update);
+  const int region_height = BLI_rcti_size_y(region_to_update);
+
+  /* Convert byte buffer to float buffer without color or alpha conversion. */
+  IMB_buffer_float_from_byte(rect_float,
+                             rect,
+                             IB_PROFILE_SRGB,
+                             IB_PROFILE_SRGB,
+                             false,
+                             region_width,
+                             region_height,
+                             src->x,
+                             dst->x);
+
+  /* Perform color space conversion from rect color space to linear. */
+  float *float_ptr = rect_float;
+  for (int i = 0; i < region_height; i++) {
+    IMB_colormanagement_colorspace_to_scene_linear(
+        float_ptr, region_width, 1, dst->channels, src->rect_colorspace, false);
+    float_ptr += 4 * dst->x;
+  }
+
+  /* Perform alpha conversion. */
+  if (IMB_alpha_affects_rgb(src)) {
+    float_ptr = rect_float;
+    for (int i = 0; i < region_height; i++) {
+      IMB_premultiply_rect_float(float_ptr, dst->channels, region_width, 1);
+      float_ptr += 4 * dst->x;
+    }
+  }
+}
+
 void IMB_float_from_rect(ImBuf *ibuf)
 {
   float *rect_float;
@@ -792,33 +848,14 @@ void IMB_float_from_rect(ImBuf *ibuf)
     }
 
     ibuf->channels = 4;
-  }
-
-  /* first, create float buffer in non-linear space */
-  IMB_buffer_float_from_byte(rect_float,
-                             (unsigned char *)ibuf->rect,
-                             IB_PROFILE_SRGB,
-                             IB_PROFILE_SRGB,
-                             false,
-                             ibuf->x,
-                             ibuf->y,
-                             ibuf->x,
-                             ibuf->x);
-
-  /* then make float be in linear space */
-  IMB_colormanagement_colorspace_to_scene_linear(
-      rect_float, ibuf->x, ibuf->y, ibuf->channels, ibuf->rect_colorspace, false);
-
-  /* byte buffer is straight alpha, float should always be premul */
-  if (IMB_alpha_affects_rgb(ibuf)) {
-    IMB_premultiply_rect_float(rect_float, ibuf->channels, ibuf->x, ibuf->y);
-  }
-
-  if (ibuf->rect_float == NULL) {
     ibuf->rect_float = rect_float;
     ibuf->mall |= IB_rectfloat;
     ibuf->flags |= IB_rectfloat;
   }
+
+  rcti region_to_update;
+  BLI_rcti_init(&region_to_update, 0, ibuf->x, 0, ibuf->y);
+  IMB_float_from_rect_ex(ibuf, ibuf, &region_to_update);
 }
 
 /** \} */