Compositor: Add support for canvas compositing

This commit adds functionality for operations that require pixel
translation or resizing on "Full Frame" mode, allowing to adjust
their canvas. It fixes most cropping issues in translate, scale,
rotate and transform nodes by adjusting their canvas to the result,
instead of the input canvas.

Operations output buffer is still always on (0,0) position for
easier image algorithm implementation, even when the
canvas is not.

Current limitations (will be addressed on bcon2):
- Displayed translation in Viewer node is limited to 6000px.
- When scaling up the canvas size is limited to the
 scene resolution size x 1.5 . From that point it crops.

If none of these limitations are hit, the Viewer node displays
the full input with any translation.

Differential Revision: https://developer.blender.org/D12466

1 files changed, 46 insertions, 18 deletions

diff --git a/source/blender/compositor/intern/COM_FullFrameExecutionModel.cc b/source/blender/compositor/intern/COM_FullFrameExecutionModel.cc
index 957bbe24e5f..c44a168390b 100644
--- a/source/blender/compositor/intern/COM_FullFrameExecutionModel.cc
+++ b/source/blender/compositor/intern/COM_FullFrameExecutionModel.cc
@@ -74,34 +74,61 @@ void FullFrameExecutionModel::determine_areas_to_render_and_reads()
   }
 }
 
-Vector<MemoryBuffer *> FullFrameExecutionModel::get_input_buffers(NodeOperation *op)
+/**
+ * Returns input buffers with an offset relative to given output coordinates. Returned memory
+ * buffers must be deleted.
+ */
+Vector<MemoryBuffer *> FullFrameExecutionModel::get_input_buffers(NodeOperation *op,
+                                                                  const int output_x,
+                                                                  const int output_y)
 {
   const int num_inputs = op->getNumberOfInputSockets();
   Vector<MemoryBuffer *> inputs_buffers(num_inputs);
   for (int i = 0; i < num_inputs; i++) {
-    NodeOperation *input_op = op->get_input_operation(i);
-    inputs_buffers[i] = active_buffers_.get_rendered_buffer(input_op);
+    NodeOperation *input = op->get_input_operation(i);
+    const int offset_x = (input->get_canvas().xmin - op->get_canvas().xmin) + output_x;
+    const int offset_y = (input->get_canvas().ymin - op->get_canvas().ymin) + output_y;
+    MemoryBuffer *buf = active_buffers_.get_rendered_buffer(input);
+
+    rcti rect = buf->get_rect();
+    BLI_rcti_translate(&rect, offset_x, offset_y);
+    inputs_buffers[i] = new MemoryBuffer(
+        buf->getBuffer(), buf->get_num_channels(), rect, buf->is_a_single_elem());
   }
   return inputs_buffers;
 }
 
-MemoryBuffer *FullFrameExecutionModel::create_operation_buffer(NodeOperation *op)
+MemoryBuffer *FullFrameExecutionModel::create_operation_buffer(NodeOperation *op,
+                                                               const int output_x,
+                                                               const int output_y)
 {
+  rcti rect;
+  BLI_rcti_init(&rect, output_x, output_x + op->getWidth(), output_y, output_y + op->getHeight());
+
   const DataType data_type = op->getOutputSocket(0)->getDataType();
   const bool is_a_single_elem = op->get_flags().is_constant_operation;
-  return new MemoryBuffer(data_type, op->get_canvas(), is_a_single_elem);
+  return new MemoryBuffer(data_type, rect, is_a_single_elem);
 }
 
 void FullFrameExecutionModel::render_operation(NodeOperation *op)
 {
-  Vector<MemoryBuffer *> input_bufs = get_input_buffers(op);
+  /* Output has no offset for easier image algorithms implementation on operations. */
+  constexpr int output_x = 0;
+  constexpr int output_y = 0;
 
   const bool has_outputs = op->getNumberOfOutputSockets() > 0;
-  MemoryBuffer *op_buf = has_outputs ? create_operation_buffer(op) : nullptr;
+  MemoryBuffer *op_buf = has_outputs ? create_operation_buffer(op, output_x, output_y) : nullptr;
   if (op->getWidth() > 0 && op->getHeight() > 0) {
-    Span<rcti> areas = active_buffers_.get_areas_to_render(op);
+    Vector<MemoryBuffer *> input_bufs = get_input_buffers(op, output_x, output_y);
+    const int op_offset_x = output_x - op->get_canvas().xmin;
+    const int op_offset_y = output_y - op->get_canvas().ymin;
+    Span<rcti> areas = active_buffers_.get_areas_to_render(op, op_offset_x, op_offset_y);
     op->render(op_buf, areas, input_bufs);
     DebugInfo::operation_rendered(op, op_buf);
+
+    for (MemoryBuffer *buf : input_bufs) {
+      delete buf;
+    }
   }
   /* Even if operation has no resolution set the empty buffer. It will be clipped with a
    * TranslateOperation from convert resolutions if linked to an operation with resolution. */
@@ -187,7 +214,8 @@ void FullFrameExecutionModel::determine_areas_to_render(NodeOperation *output_op
     std::pair<NodeOperation *, rcti> pair = stack.pop_last();
     NodeOperation *operation = pair.first;
     const rcti &render_area = pair.second;
-    if (active_buffers_.is_area_registered(operation, render_area)) {
+    if (BLI_rcti_is_empty(&render_area) ||
+        active_buffers_.is_area_registered(operation, render_area)) {
       continue;
     }
 
@@ -239,9 +267,8 @@ void FullFrameExecutionModel::get_output_render_area(NodeOperation *output_op, r
   BLI_assert(output_op->isOutputOperation(context_.isRendering()));
 
   /* By default return operation bounds (no border). */
-  const int op_width = output_op->getWidth();
-  const int op_height = output_op->getHeight();
-  BLI_rcti_init(&r_area, 0, op_width, 0, op_height);
+  rcti canvas = output_op->get_canvas();
+  r_area = canvas;
 
   const bool has_viewer_border = border_.use_viewer_border &&
                                  (output_op->get_flags().is_viewer_operation ||
@@ -251,12 +278,13 @@ void FullFrameExecutionModel::get_output_render_area(NodeOperation *output_op, r
     /* Get border with normalized coordinates. */
     const rctf *norm_border = has_viewer_border ? border_.viewer_border : border_.render_border;
 
-    /* Return de-normalized border. */
-    BLI_rcti_init(&r_area,
-                  norm_border->xmin * op_width,
-                  norm_border->xmax * op_width,
-                  norm_border->ymin * op_height,
-                  norm_border->ymax * op_height);
+    /* Return de-normalized border within canvas. */
+    const int w = output_op->getWidth();
+    const int h = output_op->getHeight();
+    r_area.xmin = canvas.xmin + norm_border->xmin * w;
+    r_area.xmax = canvas.xmin + norm_border->xmax * w;
+    r_area.ymin = canvas.ymin + norm_border->ymin * h;
+    r_area.ymax = canvas.ymin + norm_border->ymax * h;
   }
 }