Few more changes, still very glitchy

Originally committed to SVN as r278.

avisynth_prs/draw_prs.cpp

@@ -70,21 +70,24 @@ DrawPRS::~DrawPRS() {
 /////////////
 // Get frame
 PVideoFrame __stdcall DrawPRS::GetFrame(int n, IScriptEnvironment* env) {
-	// Get frame
-	//PVideoFrame avsFrame = child->GetFrame(n,env);
-	PVideoFrame avsFrame = env->NewVideoFrame(vi);
+	// Avisynth frame
+	PVideoFrame avsFrame = child->GetFrame(n,env);
 
 	try {
-		// Create the PRSFrame structure
-		PRSVideoFrame frame;
-		frame.data[0] = (char*) avsFrame->GetWritePtr();
-		frame.w = avsFrame->GetRowSize()/4;
-		frame.h = avsFrame->GetHeight();
-		frame.pitch = avsFrame->GetPitch();
-		frame.colorSpace = ColorSpace_RGB32;
+		// Check if there is anything to be drawn
+		if (file.HasDataAtFrame(n)) {
+			// Create the PRSFrame structure
+			env->MakeWritable(&avsFrame);
+			PRSVideoFrame frame;
+			frame.data[0] = (char*) avsFrame->GetWritePtr();
+			frame.w = avsFrame->GetRowSize()/4;
+			frame.h = avsFrame->GetHeight();
+			frame.pitch = avsFrame->GetPitch();
+			frame.colorSpace = ColorSpace_RGB32;
 
-		// Draw into the frame
-		file.DrawFrame(n,&frame);
+			// Draw into the frame
+			file.DrawFrame(n,&frame);
+		}
 	}
 
 	// Catch exception

prs/prs_file.cpp

@@ -287,6 +287,25 @@ void PRSFile::GetDisplayBlocksAtFrame(int n,std::vector<PRSDisplay*> &blocks) {
 }
 
 
+////////////////////////////////////////////
+// Checks if there is anything at the frame
+bool PRSFile::HasDataAtFrame(int n) {
+	// Find all blocks that match
+	unsigned int fn = n;
+	std::list<PRSEntry*>::iterator cur;
+	PRSDisplay *display;
+	for (cur=entryList.begin();cur!=entryList.end();cur++) {
+		display = PRSEntry::GetDisplay(*cur);
+		if (display) {
+			if (display->startFrame <= fn && display->endFrame >= fn) {
+				return true;
+			}
+		}
+	}
+	return false;
+}
+
+
 ///////////////////////////////////////////////////////////////
 // Gets a PRSImage by its ID, returns NULL if it doesn't exist
 PRSImage *PRSFile::GetImageByID(int id) {

prs/prs_file.h

@@ -68,6 +68,7 @@ public:
 	void Load(std::string path,bool reset=true);
 
 	void GetDisplayBlocksAtFrame(int n,std::vector<PRSDisplay*> &blocks);
+	bool HasDataAtFrame(int n);
 	void DrawFrame(int n,PRSVideoFrame *frame);
 	PRSImage *GetImageByID(int id);
 

prs/prs_video_frame.cpp

@@ -103,24 +103,24 @@ void PRSVideoFrame::Overlay(PRSVideoFrame *dstFrame,int x,int y,unsigned char al
 
 		// Draw the row
 		for (int i=0;i<rowLen;i++) {
-			// Read alpha
-			a = *src++;
-			da = *dst;
-			ia = 255-a;
-
 			// Read colors
 			sc1 = *src++;
-			dc1 = *(dst+1);
+			dc1 = *(dst);
 			sc2 = *src++;
-			dc2 = *(dst+2);
+			dc2 = *(dst+1);
 			sc3 = *src++;
-			dc3 = *(dst+3);
+			dc3 = *(dst+2);
+
+			// Read alpha
+			a = *src++;
+			da = *(dst+3);
+			ia = 255-a;
 
 			// Write colors
-			*dst++ = 255-(ia*(255-da)/255);
 			*dst++ = (sc1*a + dc1*ia)/255;
 			*dst++ = (sc2*a + dc2*ia)/255;
 			*dst++ = (sc3*a + dc3*ia)/255;
+			*dst++ = 255-(ia*(255-da)/255);
 		}
 	}
 }