Fixed a few problems with wave drawing-

Optimized so only samples inside the screens bounds are drawn.
Wave display detail is based on zoom - so you can view realy large wave files as well as indervidual samples.
Changed logic so an approximation of the wave is displayed rather then just the symetrical amplitude of the sound.
Triangles at start and end were annoying and obscured the start of the sound. made them alpha 0.7 for sound clips only.
a whole CD of music should display well and zoom smoothly now.

1 files changed, 117 insertions, 34 deletions

diff --git a/source/blender/src/drawseq.c b/source/blender/src/drawseq.c
index 153b304079e..4e664a940e1 100644
--- a/source/blender/src/drawseq.c
+++ b/source/blender/src/drawseq.c
@@ -199,37 +199,101 @@ static void drawmeta_contents(Sequence *seqm, float x1, float y1, float x2, floa
 	END_SEQ
 }
 
-static void drawseqwave(Sequence *seq, float x1, float y1, float x2, float y2)
+static void drawseqwave(Sequence *seq, float x1, float y1, float x2, float y2, int winx)
 {
-	float f, height, midy;
-	int offset, sofs, eofs;
+	float f, height, midy, clipxmin, clipxmax, sample_step;
+	int offset, offset_next, sofs, eofs;
 	signed short* s;
 	bSound *sound;
-
+	int wavesample, wavesamplemin, wavesamplemax, subsample_step=4; /* used for finding the min and max wave peaks */
+	Uint8 *stream;
+	float fsofs, feofs_sofs, sound_width; /* for faster access in the loop */
+	
 	audio_makestream(seq->sound);
-	if(seq->sound->stream==NULL) return;
-
+	if(seq->sound->stream==NULL) return;	
+	
 	if (seq->flag & SEQ_MUTE) glColor3ub(0x70, 0x80, 0x80); else glColor3ub(0x70, 0xc0, 0xc0);
-	sound = seq->sound;
+	
 	sofs = ((int)( (((float)(seq->startdisp-seq->start))/(float)G.scene->r.frs_sec)*(float)G.scene->audio.mixrate*4.0 )) & (~3);
 	eofs = ((int)( (((float)(seq->enddisp-seq->start))/(float)G.scene->r.frs_sec)*(float)G.scene->audio.mixrate*4.0 )) & (~3);
-
-	for (f=x1; f<=x2; f+=0.2) {
-		offset = (int) ((float)sofs + ((f-x1)/(x2-x1)) * (float)(eofs-sofs)) & (~3);
-		if (offset >= sound->streamlen) offset = sound->streamlen-1;
-		s = (signed short*)(((Uint8*)sound->stream) + offset);
-		midy = (y1+y2)/2;
-		height = ( ( ((float)s[0]/32768 + (float)s[1]/32768)/2 ) * (y2-y1) )/2;
-		glBegin(GL_LINES);
-		glVertex2f(f, midy-height);
-		glVertex2f(f, midy+height);
-		glEnd();
+	
+	/* clip the drawing area to the screen bounds to save time */
+	sample_step= (G.v2d->cur.xmax-G.v2d->cur.xmin)/winx;
+	clipxmin= MAX2(x1, G.v2d->cur.xmin);
+	clipxmax= MIN2(x2, G.v2d->cur.xmax);
+	
+	
+	/* Align the clipxmin to the sample step
+	this stops dithering when the wave is being clipped on the left hand side
+	With adaptive sample picking (subsample_step>4) this dosent work */
+	
+	/* f=x1;
+	while (f<clipxmin)
+		f+=sample_step;
+	clipxmin=f; */
+	
+	
+	/* when the sample step is 4 every sample of the wave is evaluated for min and max
+	values used to draw the wave, however this is slow ehrn zoomed out
+	so when the sample step is above 1 (the larger the further out the zoom is)
+	so not evaluate all samples, only some.*/
+	if (sample_step > 1)
+		subsample_step= ((int)(subsample_step*sample_step*8)) & (~3);
+	
+	/* for speedy access */
+	midy = (y1+y2)/2;
+	fsofs= (float)sofs;
+	feofs_sofs= (float)(eofs-sofs);
+	sound_width= x2-x1;
+	height= y2-y1;
+	sound = seq->sound;
+	stream = sound->stream;
+	wavesample=0;
+	
+	/* we need to get the starting offset value, excuse the duplicate code */
+	f=clipxmin;
+	offset = (int) (fsofs + ((f-x1)/sound_width) * feofs_sofs) & (~3);
+	
+	/* start the loop, draw a line per sample_step -sample_step is about 1 line drawn per pixel */
+	glBegin(GL_LINES);
+	for (f=clipxmin+sample_step; f<=clipxmax; f+=sample_step) {
+		
+		offset_next = (int) (fsofs + ((f-x1)/sound_width) * feofs_sofs) & (~3);
+		
+		/* if this is close to the last sample just exit */
+		if (offset_next >= sound->streamlen) break;
+		
+		wavesamplemin = 655360;
+		wavesamplemax = -655360;
+		
+		/*find with high and low of the waveform for this draw,
+		evaluate small samples to find this range */
+		while (offset <= offset_next) {
+			s = (signed short*)(stream+offset);
+			
+			wavesample = s[0] + s[1]/2;
+			if (wavesamplemin>wavesample)
+				wavesamplemin=wavesample;
+			if (wavesamplemax<wavesample)
+				wavesamplemax=wavesample;
+			offset+=subsample_step;
+		}
+		/* draw the wave line, looks good up close and zoomed out */
+		glVertex2f(f,  midy-(((((float)wavesamplemin)/65536)* height)/2) );
+		glVertex2f(f,  midy-(((((float)wavesamplemax)/65536)* height)/2) );
+		offset=offset_next;
 	}
+	glEnd();
 }
 
-void drawseq(Sequence *seq)
+/*
+Draw a sequencer block, bounds check alredy made
+ScrArea is currently only used to get the windows width in pixels
+so wave file sample drawing precission is zoom adjusted
+*/
+void drawseq(Sequence *seq, ScrArea *sa)
 {
-	float v1[2], v2[2], x1, x2, y1, y2;
+	float v1[2], v2[2], x1, x2, y1, y2, color_tint[4];
 	unsigned int body, dark, light;
 	int len, size;
 	short mval[2];
@@ -260,7 +324,7 @@ void drawseq(Sequence *seq)
 
 	cpack(body);
 	glRectf(x1,  y1,  x2,  y2);
-	if (seq->type == SEQ_SOUND) drawseqwave(seq, x1, y1, x2, y2);
+	if (seq->type == SEQ_SOUND) drawseqwave(seq, x1, y1, x2, y2, sa->winx);
 	EmbossBoxf(x1, y1, x2, y2, seq->flag & 1, dark, light);
 
 	v1[1]= y1;
@@ -366,7 +430,9 @@ void drawseq(Sequence *seq)
 		glRasterPos3f(x1,  y1+0.2, 0.0);
 		BMF_DrawString(G.font, strp);
 	}
+	
 
+	
 	if(seq->type < SEQ_EFFECT) {
 		/* decoration: triangles */
 		x1= seq->startdisp;
@@ -383,11 +449,18 @@ void drawseq(Sequence *seq)
 				if(seq->flag & SEQ_OVERLAP) dark= light= 0x4040FF;
 				else dark= light= 0xFFFFFF;
 			}
-		}
-		else {
+		} else {
 			cpack(body);
 		}
-
+	
+		/*Tint the color for wave display to show through */
+		if (seq->type == SEQ_SOUND) {
+			glEnable( GL_BLEND );
+			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+			glGetFloatv(GL_CURRENT_COLOR, color_tint);
+			glColor4f(color_tint[0], color_tint[1], color_tint[2], 0.7);
+		}
+		
 		glBegin(GL_TRIANGLES);
 			v1[0]= x1; glVertex2fv(v1);
 			v2[0]= x1; glVertex2fv(v2);
@@ -395,7 +468,6 @@ void drawseq(Sequence *seq)
 		glEnd();
 
 		cpack(light);
-
 		glBegin(GL_LINE_STRIP);
 			v1[0]= x1; glVertex2fv(v1);
 			v2[0]= x1; glVertex2fv(v2);
@@ -405,12 +477,6 @@ void drawseq(Sequence *seq)
 		glEnd();
 	}
 
-	if(G.moving || (seq->flag & SEQ_LEFTSEL)) {
-		cpack(0xFFFFFF);
-		glRasterPos3f(x1,  y1+0.2, 0.0);
-		sprintf(str, "%d", seq->startdisp);
-		BMF_DrawString(G.font, str);
-	}
 
 		/* right triangle */
 	if(seq->type < SEQ_EFFECT) {
@@ -427,11 +493,20 @@ void drawseq(Sequence *seq)
 		else {
 			cpack(body);
 		}
+		/*Tint the color for wave display to show through */
+		if (seq->type == SEQ_SOUND) {
+			glGetFloatv(GL_CURRENT_COLOR, color_tint);
+			glColor4f(color_tint[0], color_tint[1], color_tint[2], 0.7);
+		}
+		
 		glBegin(GL_TRIANGLES);
 			v2[0]= x2; glVertex2fv(v2);
 			v1[0]= x2; glVertex2fv(v1);
 			v2[0]-= seq->handsize; v2[1]= (y1+y2)/2.0; glVertex2fv(v2); v2[1]= y2;
 		glEnd();
+		
+		if (seq->type == SEQ_SOUND)
+			glDisable( GL_BLEND );
 
 		cpack(dark);
 		glBegin(GL_LINE_STRIP);
@@ -442,7 +517,15 @@ void drawseq(Sequence *seq)
 			glVertex2fv(v2);
 		glEnd();
 	}
-
+	
+	
+	if(G.moving || (seq->flag & SEQ_LEFTSEL)) {
+		cpack(0xFFFFFF);
+		glRasterPos3f(x1,  y1+0.2, 0.0);
+		sprintf(str, "%d", seq->startdisp);
+		BMF_DrawString(G.font, str);
+	}
+	
 	if(G.moving || (seq->flag & SEQ_RIGHTSEL)) {
 		cpack(0xFFFFFF);
 		glRasterPos3f(x2-seq->handsize/2,  y1+0.2, 0.0);
@@ -834,7 +917,7 @@ void drawseqspace(ScrArea *sa, void *spacedata)
 			{
 				/* dont draw */
 			} else {
-				drawseq(seq);
+				drawseq(seq, sa);
 			}
 			seq= seq->next;
 		}
@@ -851,7 +934,7 @@ void drawseqspace(ScrArea *sa, void *spacedata)
 			{
 				/* dont draw */
 			} else {
-				drawseq(seq);
+				drawseq(seq, sa);
 			}
 			seq= seq->next;
 		}