adjustment to coverage sample positions

src/mesa/swrast/s_aaline.c

@@ -1,4 +1,4 @@
-/* $Id: s_aaline.c,v 1.6 2001/03/12 00:48:41 gareth Exp $ */
+/* $Id: s_aaline.c,v 1.7 2001/03/28 21:37:24 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -234,8 +234,8 @@ make_sample_table(GLint xSamples, GLint ySamples, GLfloat samples[][2])
          else {
             j = i++;
          }
-         samples[j][0] = x * dx;
-         samples[j][1] = y * dy;
+         samples[j][0] = x * dx + 0.5 * dx;
+         samples[j][1] = y * dy + 0.5 * dy;
       }
    }
 }

src/mesa/swrast/s_aatriangle.c

@@ -1,4 +1,4 @@
-/* $Id: s_aatriangle.c,v 1.10 2001/03/19 02:25:36 keithw Exp $ */
+/* $Id: s_aatriangle.c,v 1.11 2001/03/28 21:37:24 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -138,25 +138,26 @@ static GLfloat
 compute_coveragef(const GLfloat v0[3], const GLfloat v1[3],
                   const GLfloat v2[3], GLint winx, GLint winy)
 {
+#define B 0.125
    static const GLfloat samples[16][2] = {
       /* start with the four corners */
-      { 0.00, 0.00 },
-      { 0.75, 0.00 },
-      { 0.00, 0.75 },
-      { 0.75, 0.75 },
+      { 0.00+B, 0.00+B },
+      { 0.75+B, 0.00+B },
+      { 0.00+B, 0.75+B },
+      { 0.75+B, 0.75+B },
       /* continue with interior samples */
-      { 0.25, 0.00 },
-      { 0.50, 0.00 },
-      { 0.00, 0.25 },
-      { 0.25, 0.25 },
-      { 0.50, 0.25 },
-      { 0.75, 0.25 },
-      { 0.00, 0.50 },
-      { 0.25, 0.50 },
-      { 0.50, 0.50 },
-      { 0.75, 0.50 },
-      { 0.25, 0.75 },
-      { 0.50, 0.75 }
+      { 0.25+B, 0.00+B },
+      { 0.50+B, 0.00+B },
+      { 0.00+B, 0.25+B },
+      { 0.25+B, 0.25+B },
+      { 0.50+B, 0.25+B },
+      { 0.75+B, 0.25+B },
+      { 0.00+B, 0.50+B },
+      { 0.25+B, 0.50+B },
+      { 0.50+B, 0.50+B },
+      { 0.75+B, 0.50+B },
+      { 0.25+B, 0.75+B },
+      { 0.50+B, 0.75+B }
    };
    const GLfloat x = (GLfloat) winx;
    const GLfloat y = (GLfloat) winy;
@@ -226,23 +227,23 @@ compute_coveragei(const GLfloat v0[3], const GLfloat v1[3],
     */
    static const GLfloat samples[15][2] = {
       /* start with the four corners */
-      { 0.00, 0.00 },
-      { 0.75, 0.00 },
-      { 0.00, 0.75 },
-      { 0.75, 0.75 },
+      { 0.00+B, 0.00+B },
+      { 0.75+B, 0.00+B },
+      { 0.00+B, 0.75+B },
+      { 0.75+B, 0.75+B },
       /* continue with interior samples */
-      { 0.25, 0.00 },
-      { 0.50, 0.00 },
-      { 0.00, 0.25 },
-      { 0.25, 0.25 },
-      { 0.50, 0.25 },
-      { 0.75, 0.25 },
-      { 0.00, 0.50 },
-      { 0.25, 0.50 },
+      { 0.25+B, 0.00+B },
+      { 0.50+B, 0.00+B },
+      { 0.00+B, 0.25+B },
+      { 0.25+B, 0.25+B },
+      { 0.50+B, 0.25+B },
+      { 0.75+B, 0.25+B },
+      { 0.00+B, 0.50+B },
+      { 0.25+B, 0.50+B },
       /*{ 0.50, 0.50 },*/
-      { 0.75, 0.50 },
-      { 0.25, 0.75 },
-      { 0.50, 0.75 }
+      { 0.75+B, 0.50+B },
+      { 0.25+B, 0.75+B },
+      { 0.50+B, 0.75+B }
    };
    const GLfloat x = (GLfloat) winx;
    const GLfloat y = (GLfloat) winy;