[Gzz-commits] gzz/gfx/liblines Lines.cxx

[Matti Katila]

CVSROOT:        /cvsroot/gzz
Module name:    gzz
Changes by:     Matti Katila <address@hidden>   02/12/10 15:40:19

Modified files:
        gfx/liblines   : Lines.cxx 

Log message:
        Fixed texture oords calculating.

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/gfx/liblines/Lines.cxx.diff?tr1=1.14&tr2=1.15&r1=text&r2=text

Patches:
Index: gzz/gfx/liblines/Lines.cxx
diff -u gzz/gfx/liblines/Lines.cxx:1.14 gzz/gfx/liblines/Lines.cxx:1.15
--- gzz/gfx/liblines/Lines.cxx:1.14     Tue Nov  5 14:00:16 2002
+++ gzz/gfx/liblines/Lines.cxx  Tue Dec 10 15:40:19 2002
@@ -44,7 +44,7 @@
            if (level != 0) size /= 2;
 
            for (int i=0; i<size; i++) {
-                line_image[i] = 0.2;
+                line_image[i] = 0;
            } 
 
            int steps = size / 8;
@@ -57,10 +57,11 @@
                }
            } else {
                switch(size) {
-               case 4: line_image[1] = 1;
-                       line_image[2] = 1; break;
-               case 2: line_image[1] = 1; break;
-               case 1: line_image[0] = 1; break;
+               case 4: line_image[1] = 0.5;
+                       line_image[2] = 0.5; break;
+               case 2: line_image[0] = 0.25;
+                       line_image[1] = 0.25; break;
+               case 1: line_image[0] = 0.125; break;
                }
            }
 
@@ -84,6 +85,34 @@
     }
 
 
+  /* How texture clipping is count?
+   * ------------------------------
+   *   line... 
+   *   +-----+---+-------+---+-----+
+   *   |     |whi|       |whi|     |
+   *   |clamp|te | black |te | clamp
+   *   |     |   |       |   |     |
+   *   +-----+---+-------+---+-----+
+   *   0     t0  3/8    5/8  t1    1
+   *          
+   *         |< >|       ¦< >|
+   *           2 pixels   2 pixels
+   *
+   *             |<width>|
+   *               
+   *-----------------------------------
+   *
+   *     t0 = 1 - t1
+   *
+   *
+   *  5/8 - 3/8      t1 - 10
+   *  ---------  =  ---------
+   *      w         2 + w + 2
+   *
+   *
+   *   t0 = 0.5 - (4+w)/8w
+   */
+
     void Lines::draw(ZPt a, ZPt b) {
         if (dbg) cout << linewidth;
         if (dbg) cout <<" x: "<< a.x << ", "<< b.x 
@@ -103,30 +132,30 @@
 
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 
-       float lp2 = 1 + linewidth/2;
-       float texcoord = 0.5;
-       texcoord *=  1/lp2;
+       // lp2 > 1
+       float total_width = 2 + linewidth/2;
        
        ZPt l = (a-b).cw90().normalized();
-       l.x *= lp2; l.y *= lp2;
+       l.x *= total_width; 
+       l.y *= total_width;
 
-       float t0 = 0.5 - texcoord;
-       float t1 = 0.5 + texcoord;
+       float t0 = 0.5 - ( (4+linewidth) / (8*linewidth) );
+       float t1 = 1 - t0;
 
        if (dbg) cout <<"t1: " << t1 <<" t0 :" << t0 << endl;
 
        glBegin(GL_QUADS);
          
-           glTexCoord2f(t0, t1);
+           glTexCoord2f(t0, 1);
            glVertex3f(a.x + l.x, a.y + l.y, a.z);
 
-           glTexCoord2f(t1, t1);
+           glTexCoord2f(t1, 1);
            glVertex3f(a.x - l.x, a.y - l.y, a.z);
 
-           glTexCoord2f(t1, t0);
+           glTexCoord2f(t1, 0);
            glVertex3f(b.x - l.x, b.y - l.y, b.z);
 
-           glTexCoord2f(t0, t0);
+           glTexCoord2f(t0, 0);
            glVertex3f(b.x + l.x, b.y + l.y, b.z);
 
        glEnd();