D627: Memory usage optimization for the compositor.

The compostor used a fixed size of 4 floats to hold pixel data. this
patch will select size of a pixel based on its type.
It uses 1 float for Value, 3 float for vector and 4 floats for color
data types.

When benchmarking on shots (opening shot of caminandes) we get a
reduction of memory of 30% and a tiny speedup as less data
transformations needs to take place (but these are negligable.

More information of the patch can be found on
https://developer.blender.org/D627 and
http://wiki.blender.org/index.php/Dev:Ref/Proposals/Compositor2014_p1.1_TD

Developers: jbakker & mdewanchand
Thanks for Sergey for his indept review.

1 files changed, 15 insertions, 6 deletions

diff --git a/source/blender/compositor/operations/COM_ReadBufferOperation.cpp b/source/blender/compositor/operations/COM_ReadBufferOperation.cpp
index 47d5fc6bcca..709c30f4015 100644
--- a/source/blender/compositor/operations/COM_ReadBufferOperation.cpp
+++ b/source/blender/compositor/operations/COM_ReadBufferOperation.cpp
@@ -24,9 +24,9 @@
 #include "COM_WriteBufferOperation.h"
 #include "COM_defines.h"
 
-ReadBufferOperation::ReadBufferOperation() : NodeOperation()
+ReadBufferOperation::ReadBufferOperation(DataType datatype) : NodeOperation()
 {
-	this->addOutputSocket(COM_DT_COLOR);
+	this->addOutputSocket(datatype);
 	this->m_single_value = false;
 	this->m_offset = 0;
 	this->m_buffer = NULL;
@@ -58,11 +58,20 @@ void ReadBufferOperation::executePixelSampled(float output[4], float x, float y,
 		/* write buffer has a single value stored at (0,0) */
 		m_buffer->read(output, 0, 0);
 	}
-	else if (sampler == COM_PS_NEAREST) {
-		m_buffer->read(output, x, y);
-	}
 	else {
-		m_buffer->readBilinear(output, x, y);
+		switch (sampler) {
+		case COM_PS_NEAREST:
+			m_buffer->read(output, x, y);
+			break;
+		case COM_PS_BILINEAR:
+		default:
+			m_buffer->readBilinear(output, x, y);
+			break;
+		case COM_PS_BICUBIC:
+			m_buffer->readBilinear(output, x, y);
+			break;
+		}
+
 	}
 }