Orange;

Until now, the zbuffer was written straight from the internal zbuffer,
which has values that are inverse-proportional (like 1.0/z) which makes
it very hard to use it for postprocess, like zblur or other composit effects
that require Z.

Based on info from ILM, the values stored for Z in exr files is the
actual distance from a camera. I think that's about time to migrate to that
convention!

By default now, after render, the z values are converted to floats. This
saves in exr files now, but not in the Iris Z files. That latter was a
blender-only anyway, so might be not a real hassle to drop. :)

You can see the difference in the image window, but notice the range now
is linear mapped from camera clipstart to clipend.

Note; I just discover that ortho Z values need a different correction...

5 files changed, 60 insertions, 18 deletions

diff --git a/source/blender/imbuf/IMB_imbuf.h b/source/blender/imbuf/IMB_imbuf.h
index 63ffeb02603..20a31f5de28 100644
--- a/source/blender/imbuf/IMB_imbuf.h
+++ b/source/blender/imbuf/IMB_imbuf.h
@@ -185,6 +185,7 @@ struct ImBuf *IMB_dupImBuf(struct ImBuf *ibuf1);
  * @attention Defined in allocimbuf.c
  */
 short addzbufImBuf(struct ImBuf * ibuf);
+short addzbuffloatImBuf(struct ImBuf * ibuf);
 
 /**
  *
@@ -468,6 +469,7 @@ void IMB_cspace(struct ImBuf *ibuf, float mat[][4]);
  * @attention Defined in allocimbuf.c
  */
 void IMB_freezbufImBuf(struct ImBuf * ibuf);
+void IMB_freezbuffloatImBuf(struct ImBuf * ibuf);
 
 /**
  *
diff --git a/source/blender/imbuf/IMB_imbuf_types.h b/source/blender/imbuf/IMB_imbuf_types.h
index 652c15afdd3..ef1aa631fc6 100644
--- a/source/blender/imbuf/IMB_imbuf_types.h
+++ b/source/blender/imbuf/IMB_imbuf_types.h
@@ -88,7 +88,8 @@ typedef struct ImBuf{
 	char	name[1023];		/**< The file name assocated with this image */
 	char	namenull;		/**< Unused don't want to remove it thought messes things up */
 	int	userflags;		/**< Used to set imbuf to Dirty and other stuff */
-	int	*zbuf;			/**< z buffer data */
+	int	*zbuf;			/**< z buffer data, original zbuffer */
+	float *zbuf_float;	/**< z buffer data, camera coordinates */
 	void *userdata;	
 	unsigned char *encodedbuffer;     /**< Compressed image only used with png currently */
 	unsigned int   encodedsize;       /**< Size of data written to encodedbuffer */
@@ -133,6 +134,7 @@ typedef enum {
 
 #define IB_mem			(1 << 14)
 #define IB_rectfloat	(1 << 15)
+#define IB_zbuffloat	(1 << 16)
 
 /*
  * The bit flag is stored in the ImBuf.ftype variable.
diff --git a/source/blender/imbuf/intern/allocimbuf.c b/source/blender/imbuf/intern/allocimbuf.c
index 51d294d2d26..0c1d182f4b2 100644
--- a/source/blender/imbuf/intern/allocimbuf.c
+++ b/source/blender/imbuf/intern/allocimbuf.c
@@ -112,6 +112,16 @@ void IMB_freezbufImBuf(struct ImBuf * ibuf)
 	ibuf->mall &= ~IB_zbuf;
 }
 
+void IMB_freezbuffloatImBuf(struct ImBuf * ibuf)
+{
+	if (ibuf==NULL) return;
+	if (ibuf->zbuf_float){
+		if (ibuf->mall & IB_zbuffloat) MEM_freeN(ibuf->zbuf_float);
+	}
+	ibuf->zbuf_float= NULL;
+	ibuf->mall &= ~IB_zbuffloat;
+}
+
 void IMB_freecmapImBuf(struct ImBuf * ibuf)
 {
 	if (ibuf==NULL) return;
@@ -129,6 +139,7 @@ void IMB_freeImBuf(struct ImBuf * ibuf)
 		imb_freerectImBuf(ibuf);
 		imb_freerectfloatImBuf(ibuf);
 		IMB_freezbufImBuf(ibuf);
+		IMB_freezbuffloatImBuf(ibuf);
 		IMB_freecmapImBuf(ibuf);
 		freeencodedbufferImBuf(ibuf);
 		MEM_freeN(ibuf);
@@ -138,18 +149,36 @@ void IMB_freeImBuf(struct ImBuf * ibuf)
 short addzbufImBuf(struct ImBuf * ibuf)
 {
 	int size;
-
+	
 	if (ibuf==NULL) return(FALSE);
 	
 	IMB_freezbufImBuf(ibuf);
-
+	
 	size = ibuf->x * ibuf->y * sizeof(unsigned int);
 	if ( (ibuf->zbuf = MEM_mallocN(size, "addzbufImBuf")) ){
 		ibuf->mall |= IB_zbuf;
 		ibuf->flags |= IB_zbuf;
 		return (TRUE);
 	}
+	
+	return (FALSE);
+}
 
+short addzbuffloatImBuf(struct ImBuf * ibuf)
+{
+	int size;
+	
+	if (ibuf==NULL) return(FALSE);
+	
+	IMB_freezbuffloatImBuf(ibuf);
+	
+	size = ibuf->x * ibuf->y * sizeof(float);
+	if ( (ibuf->zbuf_float = MEM_mallocN(size, "addzbuffloatImBuf")) ){
+		ibuf->mall |= IB_zbuffloat;
+		ibuf->flags |= IB_zbuffloat;
+		return (TRUE);
+	}
+	
 	return (FALSE);
 }
 
@@ -345,6 +374,13 @@ struct ImBuf *IMB_allocImBuf(short x, short y, uchar d, unsigned int flags, ucha
 			}
 		}
 		
+		if (flags & IB_zbuffloat){
+			if (addzbuffloatImBuf(ibuf)==FALSE){
+				IMB_freeImBuf(ibuf);
+				return NULL;
+			}
+		}
+		
 		if (flags & IB_planes){
 			if (imb_addplanesImBuf(ibuf)==FALSE){
 				IMB_freeImBuf(ibuf);
@@ -355,6 +391,7 @@ struct ImBuf *IMB_allocImBuf(short x, short y, uchar d, unsigned int flags, ucha
 	return (ibuf);
 }
 
+/* does no zbuffers? */
 struct ImBuf *IMB_dupImBuf(struct ImBuf *ibuf1)
 {
 	struct ImBuf *ibuf2, tbuf;
@@ -402,6 +439,8 @@ struct ImBuf *IMB_dupImBuf(struct ImBuf *ibuf1)
 	tbuf.planes		= ibuf2->planes;
 	tbuf.cmap		= ibuf2->cmap;
 	tbuf.encodedbuffer = ibuf2->encodedbuffer;
+	tbuf.zbuf= NULL;
+	tbuf.zbuf_float= NULL;
 	
 	// set malloc flag
 	tbuf.mall		= ibuf2->mall;
diff --git a/source/blender/imbuf/intern/divers.c b/source/blender/imbuf/intern/divers.c
index cca92741275..f73431cb28e 100644
--- a/source/blender/imbuf/intern/divers.c
+++ b/source/blender/imbuf/intern/divers.c
@@ -190,6 +190,5 @@ void IMB_rect_from_float(struct ImBuf *ibuf)
 		to += 4; 
 		tof += 4;
 	}
-				
 }
 
diff --git a/source/blender/imbuf/intern/openexr/openexr_api.cpp b/source/blender/imbuf/intern/openexr/openexr_api.cpp
index 1fefe48c227..b310f128d8e 100644
--- a/source/blender/imbuf/intern/openexr/openexr_api.cpp
+++ b/source/blender/imbuf/intern/openexr/openexr_api.cpp
@@ -167,7 +167,7 @@ static short imb_save_openexr_half(struct ImBuf *ibuf, char *name, int flags)
 	
 	int width = ibuf->x;
 	int height = ibuf->y;
-	int write_zbuf = (flags & IB_zbuf) && ibuf->zbuf != NULL;   // summarize
+	int write_zbuf = (flags & IB_zbuffloat) && ibuf->zbuf_float != NULL;   // summarize
 	
 	try
 	{
@@ -179,8 +179,8 @@ static short imb_save_openexr_half(struct ImBuf *ibuf, char *name, int flags)
 		header.channels().insert ("G", Channel (HALF));
 		header.channels().insert ("B", Channel (HALF));
 		header.channels().insert ("A", Channel (HALF));
-		if (write_zbuf)		// z we do as uint always
-			header.channels().insert ("Z", Channel (UINT));
+		if (write_zbuf)		// z we do as float always
+			header.channels().insert ("Z", Channel (FLOAT));
 		
 		FrameBuffer frameBuffer;			
 		OutputFile *file = new OutputFile(name, header);			
@@ -198,8 +198,8 @@ static short imb_save_openexr_half(struct ImBuf *ibuf, char *name, int flags)
 		frameBuffer.insert ("A", Slice (HALF, (char *) &pixels[0].a, xstride, ystride));
 	
 		if (write_zbuf)
-			frameBuffer.insert ("Z", Slice (UINT, (char *) ibuf->zbuf + 4*(height-1)*width,
-											sizeof(int), sizeof(int) * -width));
+			frameBuffer.insert ("Z", Slice (FLOAT, (char *) ibuf->zbuf_float + 4*(height-1)*width,
+											sizeof(float), sizeof(float) * -width));
 		if(ibuf->rect_float) {
 			float *from;
 			
@@ -257,8 +257,8 @@ static short imb_save_openexr_float(struct ImBuf *ibuf, char *name, int flags)
 	
 	int width = ibuf->x;
 	int height = ibuf->y;
-	int write_zbuf = (flags & IB_zbuf) && ibuf->zbuf != NULL;   // summarize
-	
+	int write_zbuf = (flags & IB_zbuffloat) && ibuf->zbuf_float != NULL;   // summarize
+
 	try
 	{
 		Header header (width, height);
@@ -270,7 +270,7 @@ static short imb_save_openexr_float(struct ImBuf *ibuf, char *name, int flags)
 		header.channels().insert ("B", Channel (FLOAT));
 		header.channels().insert ("A", Channel (FLOAT));
 		if (write_zbuf)
-			header.channels().insert ("Z", Channel (UINT));
+			header.channels().insert ("Z", Channel (FLOAT));
 		
 		FrameBuffer frameBuffer;			
 		OutputFile *file = new OutputFile(name, header);			
@@ -284,8 +284,8 @@ static short imb_save_openexr_float(struct ImBuf *ibuf, char *name, int flags)
 		frameBuffer.insert ("A", Slice (FLOAT,  (char *) (first+3), xstride, ystride));
 
 		if (write_zbuf)
-			frameBuffer.insert ("Z", Slice (UINT, (char *) ibuf->zbuf + 4*(height-1)*width,
-											sizeof(int), sizeof(int) * -width));
+			frameBuffer.insert ("Z", Slice (FLOAT, (char *) ibuf->zbuf_float + 4*(height-1)*width,
+											sizeof(float), sizeof(float) * -width));
 		file->setFrameBuffer (frameBuffer);				  
 		file->writePixels (height);					  
 		delete file;
@@ -407,12 +407,12 @@ struct ImBuf *imb_load_openexr(unsigned char *mem, int size, int flags)
 				frameBuffer.insert ("A", Slice (FLOAT,  (char *) (first+3), xstride, ystride, 1, 1, 1.0f));
 
 				if(exr_has_zbuffer(file)) {
-					int *firstz;
+					float *firstz;
 					
-					addzbufImBuf(ibuf);
-					firstz= ibuf->zbuf - (dw.min.x - dw.min.y*width);
+					addzbuffloatImBuf(ibuf);
+					firstz= ibuf->zbuf_float - (dw.min.x - dw.min.y*width);
 					firstz+= (height-1)*width;
-					frameBuffer.insert ("Z", Slice (UINT,  (char *)firstz , sizeof(int), -width*sizeof(int)));
+					frameBuffer.insert ("Z", Slice (FLOAT,  (char *)firstz , sizeof(float), -width*sizeof(float)));
 				}
 				
 				file->setFrameBuffer (frameBuffer);