1 files changed, 28 insertions, 7 deletions

diff --git a/source/blender/imbuf/intern/colormanagement.c b/source/blender/imbuf/intern/colormanagement.c
index ba0f10446a1..8a10af7e184 100644
--- a/source/blender/imbuf/intern/colormanagement.c
+++ b/source/blender/imbuf/intern/colormanagement.c
@@ -1057,13 +1057,19 @@ void colormanage_imbuf_make_linear(ImBuf *ibuf, const char *from_colorspace)
 
   if (ibuf->rect_float) {
     const char *to_colorspace = global_role_scene_linear;
+    const bool predivide = IMB_alpha_affects_rgb(ibuf);
 
     if (ibuf->rect) {
       imb_freerectImBuf(ibuf);
     }
 
-    IMB_colormanagement_transform(
-        ibuf->rect_float, ibuf->x, ibuf->y, ibuf->channels, from_colorspace, to_colorspace, true);
+    IMB_colormanagement_transform(ibuf->rect_float,
+                                  ibuf->x,
+                                  ibuf->y,
+                                  ibuf->channels,
+                                  from_colorspace,
+                                  to_colorspace,
+                                  predivide);
   }
 }
 
@@ -1405,6 +1411,7 @@ typedef struct DisplayBufferThread {
   int channels;
   float dither;
   bool is_data;
+  bool predivide;
 
   const char *byte_colorspace;
   const char *float_colorspace;
@@ -1469,6 +1476,7 @@ static void display_buffer_init_handle(void *handle_v,
   handle->channels = channels;
   handle->dither = dither;
   handle->is_data = is_data;
+  handle->predivide = IMB_alpha_affects_rgb(ibuf);
 
   handle->byte_colorspace = init_data->byte_colorspace;
   handle->float_colorspace = init_data->float_colorspace;
@@ -1486,6 +1494,7 @@ static void display_buffer_apply_get_linear_buffer(DisplayBufferThread *handle,
 
   bool is_data = handle->is_data;
   bool is_data_display = handle->cm_processor->is_data_result;
+  bool predivide = handle->predivide;
 
   if (!handle->buffer) {
     unsigned char *byte_buffer = handle->byte_buffer;
@@ -1534,7 +1543,7 @@ static void display_buffer_apply_get_linear_buffer(DisplayBufferThread *handle,
 
     if (!is_data && !is_data_display) {
       IMB_colormanagement_transform(
-          linear_buffer, width, height, channels, from_colorspace, to_colorspace, true);
+          linear_buffer, width, height, channels, from_colorspace, to_colorspace, predivide);
     }
 
     *is_straight_alpha = false;
@@ -1590,13 +1599,13 @@ static void *do_display_buffer_apply_thread(void *handle_v)
     }
   }
   else {
-    bool is_straight_alpha, predivide;
+    bool is_straight_alpha;
     float *linear_buffer = MEM_mallocN(((size_t)channels) * width * height * sizeof(float),
                                        "color conversion linear buffer");
 
     display_buffer_apply_get_linear_buffer(handle, height, linear_buffer, &is_straight_alpha);
 
-    predivide = is_straight_alpha == false;
+    bool predivide = handle->predivide && (is_straight_alpha == false);
 
     if (is_data) {
       /* special case for data buffers - no color space conversions,
@@ -2178,6 +2187,7 @@ void IMB_colormanagement_imbuf_to_srgb_texture(unsigned char *out_buffer,
 
   /* TODO(brecht): make this multithreaded, or at least process in batches. */
   const unsigned char *in_buffer = (unsigned char *)ibuf->rect;
+  const bool use_premultiply = IMB_alpha_affects_rgb(ibuf);
 
   for (int y = 0; y < height; y++) {
     const size_t in_offset = (offset_y + y) * ibuf->x + offset_x;
@@ -2192,11 +2202,13 @@ void IMB_colormanagement_imbuf_to_srgb_texture(unsigned char *out_buffer,
         rgba_uchar_to_float(pixel, in);
         OCIO_processorApplyRGB(processor, pixel);
         linearrgb_to_srgb_v3_v3(pixel, pixel);
-        mul_v3_fl(pixel, pixel[3]);
+        if (use_premultiply) {
+          mul_v3_fl(pixel, pixel[3]);
+        }
         rgba_float_to_uchar(out, pixel);
       }
     }
-    else {
+    else if (use_premultiply) {
       /* Premultiply only. */
       for (int x = 0; x < width; x++, in += 4, out += 4) {
         out[0] = (in[0] * in[3]) >> 8;
@@ -2205,6 +2217,15 @@ void IMB_colormanagement_imbuf_to_srgb_texture(unsigned char *out_buffer,
         out[3] = in[3];
       }
     }
+    else {
+      /* Copy only. */
+      for (int x = 0; x < width; x++, in += 4, out += 4) {
+        out[0] = in[0];
+        out[1] = in[1];
+        out[2] = in[2];
+        out[3] = in[3];
+      }
+    }
   }
 }