diff options
| -rw-r--r-- | src/mesa/pipe/draw/draw_wide_prims.c | 75 |
1 files changed, 69 insertions, 6 deletions
diff --git a/src/mesa/pipe/draw/draw_wide_prims.c b/src/mesa/pipe/draw/draw_wide_prims.c index 9759e7e2e8..4c7e279b20 100644 --- a/src/mesa/pipe/draw/draw_wide_prims.c +++ b/src/mesa/pipe/draw/draw_wide_prims.c @@ -76,7 +76,6 @@ static void passthrough_tri( struct draw_stage *stage, /** * Draw a wide line by drawing a quad (two triangles). - * XXX still need line stipple. * XXX need to disable polygon stipple. */ static void wide_line( struct draw_stage *stage, @@ -103,12 +102,9 @@ static void wide_line( struct draw_stage *stage, /* * Draw wide line as a quad (two tris) by "stretching" the line along * X or Y. - * XXX For AA lines, the quad corners have to be computed in a - * more sophisticated way. + * We need to tweak coords in several ways to be conformant here. */ - /* need to tweak coords in several ways to be conformant here */ - if (dx > dy) { /* x-major line */ pos0[1] = pos0[1] - half_width - 0.25f; @@ -166,6 +162,70 @@ static void wide_line( struct draw_stage *stage, /** + * Draw a wide line by drawing a quad, using geometry which will + * fullfill GL's antialiased line requirements. + */ +static void wide_line_aa(struct draw_stage *stage, + struct prim_header *header) +{ + const struct wide_stage *wide = wide_stage(stage); + const float half_width = wide->half_line_width; + struct prim_header tri; + struct vertex_header *v[4]; + float *pos; + float dx = header->v[1]->data[0][0] - header->v[0]->data[0][0]; + float dy = header->v[1]->data[0][1] - header->v[0]->data[0][1]; + const float len = sqrt(dx * dx + dy * dy); + uint i; + + dx = dx * half_width / len; + dy = dy * half_width / len; + + /* allocate/dup new verts */ + for (i = 0; i < 4; i++) { + v[i] = dup_vert(stage, header->v[i/2], i); + } + + /* + * Quad for line from v0 to v1: + * + * 1 3 + * +-------------------------+ + * | | + * *v0 v1* + * | | + * +-------------------------+ + * 0 2 + */ + + pos = v[0]->data[0]; + pos[0] += dy; + pos[1] -= dx; + + pos = v[1]->data[0]; + pos[0] -= dy; + pos[1] += dx; + + pos = v[2]->data[0]; + pos[0] += dy; + pos[1] -= dx; + + pos = v[3]->data[0]; + pos[0] -= dy; + pos[1] += dx; + + tri.det = header->det; /* only the sign matters */ + + tri.v[0] = v[2]; tri.v[1] = v[1]; tri.v[2] = v[0]; + stage->next->tri( stage->next, &tri ); + + tri.v[0] = v[3]; tri.v[1] = v[1]; tri.v[2] = v[2]; + stage->next->tri( stage->next, &tri ); + +} + + +/** * Set the vertex texcoords for sprite mode. * Coords may be left untouched or set to a right-side-up or upside-down * orientation. @@ -319,7 +379,10 @@ static void wide_first_line( struct draw_stage *stage, wide->half_line_width = 0.5f * draw->rasterizer->line_width; if (draw->rasterizer->line_width != 1.0) { - wide->stage.line = wide_line; + if (draw->rasterizer->line_smooth) + wide->stage.line = wide_line_aa; + else + wide->stage.line = wide_line; } else { wide->stage.line = passthrough_line; |