Cycles: change preview "resolution divider" that gave the number of lower

resolutions to render, to a "start resolution" which gives the resolution
to start at.

This avoids unnecessary rendering of small resolutions in small viewports,
and avoids long waiting on big viewports.

intern/cycles/blender/addon/properties.py

@@ -242,11 +242,11 @@ class CyclesRenderSettings(bpy.types.PropertyGroup):
                 default=1024,
                 )
 
-        cls.resolution_divider = IntProperty(
-                name="Resolution Divider",
-                description="For viewport render, the number of lower resolutions to render before the full resolution",
-                min=1, max=512,
-                default=4,
+        cls.preview_start_resolution = IntProperty(
+                name="Start Resolution",
+                description="Resolution to start rendering preview at, progressively increasing it to the full viewport size",
+                min=8, max=16384,
+                default=64,
                 )
 
         cls.debug_reset_timeout = FloatProperty(

intern/cycles/blender/addon/ui.py

@@ -216,7 +216,7 @@ class CyclesRender_PT_performance(CyclesButtonsPanel, Panel):
 
         sub = col.column(align=True)
         sub.label(text="Viewport:")
-        sub.prop(cscene, "resolution_divider")
+        sub.prop(cscene, "preview_start_resolution")
 
 
 class CyclesRender_PT_layers(CyclesButtonsPanel, Panel):

intern/cycles/blender/blender_sync.cpp

@@ -368,7 +368,7 @@ SessionParams BlenderSync::get_session_params(BL::RenderEngine b_engine, BL::Use
 		params.tile_size = make_int2(tile_x, tile_y);
 	}
 
-	params.resolution = 1 << get_int(cscene, "resolution_divider");
+	params.start_resolution = get_int(cscene, "preview_start_resolution");
 
 	/* other parameters */
 	params.threads = b_scene.render().threads();
@@ -379,7 +379,7 @@ SessionParams BlenderSync::get_session_params(BL::RenderEngine b_engine, BL::Use
 
 	if(background) {
 		params.progressive = false;
-		params.resolution = 1;
+		params.start_resolution = INT_MAX;
 	}
 	else
 		params.progressive = true;

intern/cycles/render/session.cpp

@@ -36,7 +36,7 @@ CCL_NAMESPACE_BEGIN
 
 Session::Session(const SessionParams& params_)
 : params(params_),
-  tile_manager(params.progressive, params.samples, params.tile_size, params.resolution,
+  tile_manager(params.progressive, params.samples, params.tile_size, params.start_resolution,
   	(params.background)? 1: max(params.device.multi_devices.size(), 1))
 {
 	device_use_gl = ((params.device.type != DEVICE_CPU) && !params.background);
@@ -343,7 +343,7 @@ bool Session::acquire_tile(Device *tile_device, RenderTile& rtile)
 	rtile.h = tile.h;
 	rtile.start_sample = tile_manager.state.sample;
 	rtile.num_samples = tile_manager.state.num_samples;
-	rtile.resolution = tile_manager.state.resolution;
+	rtile.resolution = tile_manager.state.resolution_divider;
 
 	tile_lock.unlock();
 
@@ -668,7 +668,7 @@ void Session::update_scene()
 void Session::update_status_time(bool show_pause, bool show_done)
 {
 	int sample = tile_manager.state.sample;
-	int resolution = tile_manager.state.resolution;
+	int resolution = tile_manager.state.resolution_divider;
 	int num_tiles = tile_manager.state.num_tiles;
 	int tile = tile_manager.state.num_rendered_tiles;
 
@@ -757,7 +757,7 @@ void Session::tonemap()
 	task.rgba = display->rgba.device_pointer;
 	task.buffer = buffers->buffer.device_pointer;
 	task.sample = tile_manager.state.sample;
-	task.resolution = tile_manager.state.resolution;
+	task.resolution = tile_manager.state.resolution_divider;
 	tile_manager.state.buffer.get_offset_stride(task.offset, task.stride);
 
 	if(task.w > 0 && task.h > 0) {

intern/cycles/render/session.h

@@ -48,7 +48,7 @@ public:
 	bool experimental;
 	int samples;
 	int2 tile_size;
-	int resolution;
+	int start_resolution;
 	int threads;
 
 	double cancel_timeout;
@@ -64,7 +64,7 @@ public:
 		experimental = false;
 		samples = INT_MAX;
 		tile_size = make_int2(64, 64);
-		resolution = 4;
+		start_resolution = INT_MAX;
 		threads = 0;
 
 		cancel_timeout = 0.1;
@@ -81,7 +81,7 @@ public:
 		&& progressive == params.progressive
 		&& experimental == params.experimental
 		&& tile_size == params.tile_size
-		&& resolution == params.resolution
+		&& start_resolution == params.start_resolution
 		&& threads == params.threads
 		&& cancel_timeout == params.cancel_timeout
 		&& reset_timeout == params.reset_timeout

intern/cycles/render/tile.cpp

@@ -23,11 +23,11 @@
 
 CCL_NAMESPACE_BEGIN
 
-TileManager::TileManager(bool progressive_, int num_samples_, int2 tile_size_, int resolution_, int num_devices_)
+TileManager::TileManager(bool progressive_, int num_samples_, int2 tile_size_, int start_resolution_, int num_devices_)
 {
 	progressive = progressive_;
 	tile_size = tile_size_;
-	resolution = resolution_;
+	start_resolution = start_resolution_;
 	num_devices = num_devices_;
 
 	BufferParams buffer_params;
@@ -42,6 +42,18 @@ void TileManager::reset(BufferParams& params_, int num_samples_)
 {
 	params = params_;
 
+	int divider = 1;
+	int w = params.width, h = params.height;
+
+	if(start_resolution != INT_MAX) {
+		while(w*h > start_resolution*start_resolution) {
+			w = max(1, w/2); 
+			h = max(1, h/2); 
+
+			divider *= 2;
+		}
+	}
+
 	num_samples = num_samples_;
 
 	state.buffer = BufferParams();
@@ -49,7 +61,7 @@ void TileManager::reset(BufferParams& params_, int num_samples_)
 	state.num_tiles = 0;
 	state.num_rendered_tiles = 0;
 	state.num_samples = 0;
-	state.resolution = resolution;
+	state.resolution_divider = divider;
 	state.tiles.clear();
 }
 
@@ -60,7 +72,7 @@ void TileManager::set_samples(int num_samples_)
 
 void TileManager::set_tiles()
 {
-	int resolution = state.resolution;
+	int resolution = state.resolution_divider;
 	int image_w = max(1, params.width/resolution);
 	int image_h = max(1, params.height/resolution);
 
@@ -104,7 +116,7 @@ list<Tile>::iterator TileManager::next_center_tile(int device)
 {
 	list<Tile>::iterator iter, best = state.tiles.end();
 
-	int resolution = state.resolution;
+	int resolution = state.resolution_divider;
 	int image_w = max(1, params.width/resolution);
 	int image_h = max(1, params.height/resolution);
 
@@ -167,7 +179,7 @@ bool TileManager::next_tile(Tile& tile, int device)
 
 bool TileManager::done()
 {
-	return (state.sample+state.num_samples >= num_samples && state.resolution == 1);
+	return (state.sample+state.num_samples >= num_samples && state.resolution_divider == 1);
 }
 
 bool TileManager::next()
@@ -175,9 +187,9 @@ bool TileManager::next()
 	if(done())
 		return false;
 
-	if(progressive && state.resolution > 1) {
+	if(progressive && state.resolution_divider > 1) {
 		state.sample = 0;
-		state.resolution /= 2;
+		state.resolution_divider /= 2;
 		state.num_samples = 1;
 		set_tiles();
 	}
@@ -189,7 +201,7 @@ bool TileManager::next()
 		else
 			state.num_samples = num_samples;
 
-		state.resolution = 1;
+		state.resolution_divider = 1;
 		set_tiles();
 	}
 

intern/cycles/render/tile.h

@@ -51,13 +51,13 @@ public:
 		BufferParams buffer;
 		int sample;
 		int num_samples;
-		int resolution;
+		int resolution_divider;
 		int num_tiles;
 		int num_rendered_tiles;
 		list<Tile> tiles;
 	} state;
 
-	TileManager(bool progressive, int num_samples, int2 tile_size, int resolution, int num_devices = 1);
+	TileManager(bool progressive, int num_samples, int2 tile_size, int start_resolution, int num_devices = 1);
 	~TileManager();
 
 	void reset(BufferParams& params, int num_samples);
@@ -72,10 +72,8 @@ protected:
 	bool progressive;
 	int num_samples;
 	int2 tile_size;
-	int resolution;
-	int num_devices;
-
 	int start_resolution;
+	int num_devices;
 
 	list<Tile>::iterator next_center_tile(int device = 0);
 };