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gallium: initial code for wide/AA line drawing

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This commit is contained in:
Brian
2008-02-12 19:14:58 -07:00
parent 9af687c530
commit e20e89e482
1 changed files with 69 additions and 6 deletions
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src/mesa/pipe/draw/draw_wide_prims.c
+69 -6
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@@ -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;
@@ -165,6 +161,70 @@ 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
@@ -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;