diff options
| -rw-r--r-- | src/mesa/main/points.c | 93 |
1 files changed, 57 insertions, 36 deletions
diff --git a/src/mesa/main/points.c b/src/mesa/main/points.c index 2aebb72472d..fe4810eaebe 100644 --- a/src/mesa/main/points.c +++ b/src/mesa/main/points.c @@ -1,4 +1,4 @@ -/* $Id: points.c,v 1.10 2000/06/28 23:11:10 brianp Exp $ */ +/* $Id: points.c,v 1.11 2000/07/15 03:13:43 brianp Exp $ */ /* * Mesa 3-D graphics library @@ -521,6 +521,17 @@ multitextured_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) } +/* + * NOTES on aa point rasterization: + * + * Let d = distance of fragment center from vertex. + * if d < rmin2 then + * fragment has 100% coverage + * else if d > rmax2 then + * fragment has 0% coverage + * else + * fragement has % coverage = (d - rmin2) / (rmax2 - rmin2) + */ /* @@ -534,7 +545,7 @@ antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) const GLfloat radius = ctx->Point.Size * 0.5F; const GLfloat rmin = radius - 0.7071F; /* 0.7071 = sqrt(2)/2 */ const GLfloat rmax = radius + 0.7071F; - const GLfloat rmin2 = rmin * rmin; + const GLfloat rmin2 = MAX2(0.0, rmin * rmin); const GLfloat rmax2 = rmax * rmax; const GLfloat cscale = 256.0F / (rmax2 - rmin2); GLuint i; @@ -546,11 +557,13 @@ antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) GLint red, green, blue, alpha; GLfloat s, t, u; GLfloat s1, t1, u1; + GLfloat vx = VB->Win.data[i][0]; + GLfloat vy = VB->Win.data[i][1]; - GLint xmin = (GLint) (VB->Win.data[i][0] - radius); - GLint xmax = (GLint) (VB->Win.data[i][0] + radius); - GLint ymin = (GLint) (VB->Win.data[i][1] - radius); - GLint ymax = (GLint) (VB->Win.data[i][1] + radius); + GLint xmin = (GLint) (vx - radius); + GLint xmax = (GLint) (vx + radius); + GLint ymin = (GLint) (vy - radius); + GLint ymax = (GLint) (vy + radius); GLint z = (GLint) (VB->Win.data[i][2] + ctx->PointZoffset); red = VB->ColorPtr->data[i][0]; @@ -621,15 +634,19 @@ antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) } } - for (y=ymin;y<=ymax;y++) { - for (x=xmin;x<=xmax;x++) { - GLfloat dx = x/*+0.5F*/ - VB->Win.data[i][0]; - GLfloat dy = y/*+0.5F*/ - VB->Win.data[i][1]; - GLfloat dist2 = dx*dx + dy*dy; - if (dist2<rmax2) { + /* translate by a half pixel to simplify math below */ + vx -= 0.5F; + vx -= 0.5F; + + for (y = ymin; y <= ymax; y++) { + for (x = xmin; x <= xmax; x++) { + const GLfloat dx = x - vx; + const GLfloat dy = y - vy; + const GLfloat dist2 = dx*dx + dy*dy; + if (dist2 < rmax2) { alpha = VB->ColorPtr->data[i][3]; - if (dist2>=rmin2) { - GLint coverage = (GLint) (256.0F-(dist2-rmin2)*cscale); + if (dist2 >= rmin2) { + GLint coverage = (GLint) (256.0F - (dist2 - rmin2) * cscale); /* coverage is in [0,256] */ alpha = (alpha * coverage) >> 8; } @@ -656,25 +673,29 @@ antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) GLint x, y, z; GLint red, green, blue, alpha; - xmin = (GLint) (VB->Win.data[i][0] - radius); - xmax = (GLint) (VB->Win.data[i][0] + radius); - ymin = (GLint) (VB->Win.data[i][1] - radius); - ymax = (GLint) (VB->Win.data[i][1] + radius); + xmin = (GLint) (VB->Win.data[i][0] - 0.0 - radius); + xmax = (GLint) (VB->Win.data[i][0] - 0.0 + radius); + ymin = (GLint) (VB->Win.data[i][1] - 0.0 - radius); + ymax = (GLint) (VB->Win.data[i][1] - 0.0 + radius); z = (GLint) (VB->Win.data[i][2] + ctx->PointZoffset); red = VB->ColorPtr->data[i][0]; green = VB->ColorPtr->data[i][1]; blue = VB->ColorPtr->data[i][2]; - for (y=ymin;y<=ymax;y++) { - for (x=xmin;x<=xmax;x++) { - GLfloat dx = x/*+0.5F*/ - VB->Win.data[i][0]; - GLfloat dy = y/*+0.5F*/ - VB->Win.data[i][1]; - GLfloat dist2 = dx*dx + dy*dy; - if (dist2<rmax2) { + /* + printf("point %g, %g\n", VB->Win.data[i][0], VB->Win.data[i][1]); + printf("%d..%d X %d..%d\n", xmin, xmax, ymin, ymax); + */ + for (y = ymin; y <= ymax; y++) { + for (x = xmin; x <= xmax; x++) { + const GLfloat dx = x + 0.5F - VB->Win.data[i][0]; + const GLfloat dy = y + 0.5F - VB->Win.data[i][1]; + const GLfloat dist2 = dx*dx + dy*dy; + if (dist2 < rmax2) { alpha = VB->ColorPtr->data[i][3]; - if (dist2>=rmin2) { - GLint coverage = (GLint) (256.0F-(dist2-rmin2)*cscale); + if (dist2 >= rmin2) { + GLint coverage = (GLint) (256.0F - (dist2 - rmin2) * cscale); /* coverage is in [0,256] */ alpha = (alpha * coverage) >> 8; } @@ -1104,9 +1125,9 @@ dist_atten_antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) } rmin = radius - 0.7071F; /* 0.7071 = sqrt(2)/2 */ rmax = radius + 0.7071F; - rmin2 = rmin*rmin; - rmax2 = rmax*rmax; - cscale = 256.0F / (rmax2-rmin2); + rmin2 = MAX2(0.0, rmin * rmin); + rmax2 = rmax * rmax; + cscale = 256.0F / (rmax2 - rmin2); xmin = (GLint) (VB->Win.data[i][0] - radius); xmax = (GLint) (VB->Win.data[i][0] + radius); @@ -1184,9 +1205,9 @@ dist_atten_antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) for (y = ymin; y <= ymax; y++) { for (x = xmin; x <= xmax; x++) { - GLfloat dx = x/*+0.5F*/ - VB->Win.data[i][0]; - GLfloat dy = y/*+0.5F*/ - VB->Win.data[i][1]; - GLfloat dist2 = dx*dx + dy*dy; + const GLfloat dx = x + 0.5F - VB->Win.data[i][0]; + const GLfloat dy = y + 0.5F - VB->Win.data[i][1]; + const GLfloat dist2 = dx*dx + dy*dy; if (dist2 < rmax2) { alpha = VB->ColorPtr->data[i][3]; if (dist2 >= rmin2) { @@ -1230,7 +1251,7 @@ dist_atten_antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) } rmin = radius - 0.7071F; /* 0.7071 = sqrt(2)/2 */ rmax = radius + 0.7071F; - rmin2 = rmin * rmin; + rmin2 = MAX2(0.0, rmin * rmin); rmax2 = rmax * rmax; cscale = 256.0F / (rmax2 - rmin2); @@ -1246,9 +1267,9 @@ dist_atten_antialiased_rgba_points( GLcontext *ctx, GLuint first, GLuint last ) for (y = ymin; y <= ymax; y++) { for (x = xmin; x <= xmax; x++) { - GLfloat dx = x/*+0.5F*/ - VB->Win.data[i][0]; - GLfloat dy = y/*+0.5F*/ - VB->Win.data[i][1]; - GLfloat dist2 = dx * dx + dy * dy; + const GLfloat dx = x + 0.5F - VB->Win.data[i][0]; + const GLfloat dy = y + 0.5F - VB->Win.data[i][1]; + const GLfloat dist2 = dx * dx + dy * dy; if (dist2 < rmax2) { alpha = VB->ColorPtr->data[i][3]; if (dist2 >= rmin2) { |