Revision: 16226
http://projects.blender.org/plugins/scmsvn/viewcvs.php?view=rev&root=bf-blender&revision=16226
Author: aligorith
Date: 2008-08-22 13:46:59 +0200 (Fri, 22 Aug 2008)
Log Message:
-----------
Grease Pencil - Drawing Improvements:
This commit finishes the work started in the previous commit.
1) Reduced the effects of 'shrinking' lines with acute angles (*)
2) Ends of strokes now get crude end-caps which look ok for most purposes (they
are really just simple trapeziums not fancy semicircles)
* Note: some shrinking does still occur if the stroke was drawn quickly enough
for few points to be recorded. Also, although there are still zones of
overlapping when there are acute angles, this is reduced to steeper angles (and
is not too bad considering real-life materials)
Modified Paths:
--------------
trunk/blender/source/blender/src/drawgpencil.c
Modified: trunk/blender/source/blender/src/drawgpencil.c
===================================================================
--- trunk/blender/source/blender/src/drawgpencil.c 2008-08-22 10:27:16 UTC
(rev 16225)
+++ trunk/blender/source/blender/src/drawgpencil.c 2008-08-22 11:46:59 UTC
(rev 16226)
@@ -450,7 +450,7 @@
static void gp_draw_stroke (bGPDspoint *points, int totpoints, short
thickness, short dflag, short sflag, short debug, int winx, int winy)
{
/* if thickness is less than 3, 'smooth' opengl lines look better */
- if ((thickness < 3) || (G.rt==0)) {
+ if (thickness < 3) {
bGPDspoint *pt;
int i;
@@ -472,19 +472,15 @@
bGPDspoint *pt1, *pt2;
float pm[2];
int i;
- short n;
glShadeModel(GL_FLAT);
+ glBegin(GL_QUADS);
- glPointSize(3.0f); // temp
-
- for (n= 0; n < 2; n++) { // temp
- glBegin((n)?GL_POINTS:GL_QUADS);
-
for (i=0, pt1=points, pt2=points+1; i < (totpoints-1); i++,
pt1++, pt2++) {
float s0[2], s1[2]; /* segment 'center'
points */
float t0[2], t1[2]; /* tesselated
coordinates */
float m1[2], m2[2]; /* gradient and normal
*/
+ float mt[2], sc[2]; /* gradient for
thickness, point for end-cap */
float pthick; /* thickness at segment
point */
/* get x and y coordinates from points */
@@ -502,42 +498,75 @@
/* calculate gradient and normal - 'angle'=(ny/nx) */
m1[1]= s1[1] - s0[1];
m1[0]= s1[0] - s0[0];
+ Normalize2(m1);
m2[1]= -m1[0];
m2[0]= m1[1];
- Normalize2(m2);
/* always use pressure from first point here */
pthick= (pt1->pressure * thickness);
/* if the first segment, start of segment is segment's
normal */
if (i == 0) {
- // TODO: also draw/do a round end-cap first
+ /* draw start cap first
+ * - make points slightly closer to center
(about halfway across)
+ */
+ mt[0]= m2[0] * pthick * 0.5;
+ mt[1]= m2[1] * pthick * 0.5;
+ sc[0]= s0[0] - (m1[0] * pthick * 0.75);
+ sc[1]= s0[1] - (m1[1] * pthick * 0.75);
+ t0[0]= sc[0] - mt[0];
+ t0[1]= sc[1] - mt[1];
+ t1[0]= sc[0] + mt[0];
+ t1[1]= sc[1] + mt[1];
+
+ glVertex2fv(t0);
+ glVertex2fv(t1);
+
/* calculate points for start of segment */
- t0[0]= s0[0] - (pthick * m2[0]);
- t0[1]= s0[1] - (pthick * m2[1]);
- t1[0]= s0[0] + (pthick * m2[0]);
- t1[1]= s0[1] + (pthick * m2[1]);
+ mt[0]= m2[0] * pthick;
+ mt[1]= m2[1] * pthick;
- /* draw this line only once */
+ t0[0]= s0[0] - mt[0];
+ t0[1]= s0[1] - mt[1];
+ t1[0]= s0[0] + mt[0];
+ t1[1]= s0[1] + mt[1];
+
+ /* draw this line twice (first to finish off
start cap, then for stroke) */
+ glVertex2fv(t1);
glVertex2fv(t0);
+ glVertex2fv(t0);
glVertex2fv(t1);
}
/* if not the first segment, use bisector of angle
between segments */
else {
- float mb[2]; /* bisector normal */
+ float mb[2]; /* bisector normal */
+ float athick, dfac; /* actual
thickness, difference between thicknesses */
/* calculate gradient of bisector (as average
of normals) */
mb[0]= (pm[0] + m2[0]) / 2;
mb[1]= (pm[1] + m2[1]) / 2;
Normalize2(mb);
+ /* calculate gradient to apply
+ * - as basis, use just pthick * bisector
gradient
+ * - if cross-section not as thick as it
should be, add extra padding to fix it
+ */
+ mt[0]= mb[0] * pthick;
+ mt[1]= mb[1] * pthick;
+ athick= Vec2Length(mt);
+ dfac= pthick - (athick * 2);
+ if ( ((athick * 2) < pthick) && (IS_EQ(athick,
pthick)==0) )
+ {
+ mt[0] += (mb[0] * dfac);
+ mt[1] += (mb[1] * dfac);
+ }
+
/* calculate points for start of segment */
- // FIXME: do we need extra padding for acute
angles?
- t0[0]= s0[0] - (pthick * mb[0]);
- t0[1]= s0[1] - (pthick * mb[1]);
- t1[0]= s0[0] + (pthick * mb[0]);
- t1[1]= s0[1] + (pthick * mb[1]);
+ t0[0]= s0[0] - mt[0];
+ t0[1]= s0[1] - mt[1];
+ t1[0]= s0[0] + mt[0];
+ t1[1]= s0[1] + mt[1];
/* draw this line twice (once for end of
current segment, and once for start of next) */
glVertex2fv(t1);
@@ -552,16 +581,36 @@
pthick= (pt2->pressure * thickness);
/* calculate points for end of segment */
- t0[0]= s1[0] - (pthick * m2[0]);
- t0[1]= s1[1] - (pthick * m2[1]);
- t1[0]= s1[0] + (pthick * m2[0]);
- t1[1]= s1[1] + (pthick * m2[1]);
+ mt[0]= m2[0] * pthick;
+ mt[1]= m2[1] * pthick;
- /* draw this line only once */
+ t0[0]= s1[0] - mt[0];
+ t0[1]= s1[1] - mt[1];
+ t1[0]= s1[0] + mt[0];
+ t1[1]= s1[1] + mt[1];
+
+ /* draw this line twice (once for end of
stroke, and once for endcap)*/
glVertex2fv(t1);
glVertex2fv(t0);
+ glVertex2fv(t0);
+ glVertex2fv(t1);
- // TODO: draw end cap as last step
+
+ /* draw end cap as last step
+ * - make points slightly closer to center
(about halfway across)
+ */
+ mt[0]= m2[0] * pthick * 0.5;
+ mt[1]= m2[1] * pthick * 0.5;
+ sc[0]= s1[0] + (m1[0] * pthick * 0.75);
+ sc[1]= s1[1] + (m1[1] * pthick * 0.75);
+
+ t0[0]= sc[0] - mt[0];
+ t0[1]= sc[1] - mt[1];
+ t1[0]= sc[0] + mt[0];
+ t1[1]= sc[1] + mt[1];
+
+ glVertex2fv(t1);
+ glVertex2fv(t0);
}
/* store stroke's 'natural' normal for next stroke to
use */
@@ -569,7 +618,6 @@
}
glEnd();
- }
}
/* draw debug points of curve on top? (original stroke points) */
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