/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* Antialiased line template.
*/
/*
* Function to render each fragment in the AA line.
* \param ix - integer fragment window X coordiante
* \param iy - integer fragment window Y coordiante
*/
static void
NAME(plot)(struct gl_context *ctx, struct LineInfo *line, int ix, int iy)
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
const GLfloat fx = (GLfloat) ix;
const GLfloat fy = (GLfloat) iy;
const GLfloat coverage = compute_coveragef(line, ix, iy);
const GLuint i = line->span.end;
(void) swrast;
if (coverage == 0.0F)
return;
line->span.end++;
line->span.array->coverage[i] = coverage;
line->span.array->x[i] = ix;
line->span.array->y[i] = iy;
/*
* Compute Z, color, texture coords, fog for the fragment by
* solving the plane equations at (ix,iy).
*/
#ifdef DO_Z
line->span.array->z[i] = (GLuint) solve_plane(fx, fy, line->zPlane);
#endif
line->span.array->rgba[i][RCOMP] = solve_plane_chan(fx, fy, line->rPlane);
line->span.array->rgba[i][GCOMP] = solve_plane_chan(fx, fy, line->gPlane);
line->span.array->rgba[i][BCOMP] = solve_plane_chan(fx, fy, line->bPlane);
line->span.array->rgba[i][ACOMP] = solve_plane_chan(fx, fy, line->aPlane);
#if defined(DO_ATTRIBS)
ATTRIB_LOOP_BEGIN
GLfloat (*attribArray)[4] = line->span.array->attribs[attr];
if (attr >= VARYING_SLOT_TEX0 && attr < VARYING_SLOT_VAR0
&& !_swrast_use_fragment_program(ctx)) {
/* texcoord w/ divide by Q */
const GLuint unit = attr - VARYING_SLOT_TEX0;
const GLfloat invQ = solve_plane_recip(fx, fy, line->attrPlane[attr][3]);
GLuint c;
for (c = 0; c < 3; c++) {
attribArray[i][c] = solve_plane(fx, fy, line->attrPlane[attr][c]) * invQ;
}
line->span.array->lambda[unit][i]
= compute_lambda(line->attrPlane[attr][0],
line->attrPlane[attr][1], invQ,
line->texWidth[attr], line->texHeight[attr]);
}
else {
/* non-texture attrib */
const GLfloat invW = solve_plane_recip(fx, fy, line->wPlane);
GLuint c;
for (c = 0; c < 4; c++) {
attribArray[i][c] = solve_plane(fx, fy, line->attrPlane[attr][c]) * invW;
}
}
ATTRIB_LOOP_END
#endif
if (line->span.end == SWRAST_MAX_WIDTH) {
_swrast_write_rgba_span(ctx, &(line->span));
line->span.end = 0; /* reset counter */
}
}
/*
* Line setup
*/
static void
NAME(line)(struct gl_context *ctx, const SWvertex *v0, const SWvertex *v1)
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLfloat tStart, tEnd; /* segment start, end along line length */
GLboolean inSegment;
GLint iLen, i;
/* Init the LineInfo struct */
struct LineInfo line;
line.x0 = v0->attrib[VARYING_SLOT_POS][0];
line.y0 = v0->attrib[VARYING_SLOT_POS][1];
line.x1 = v1->attrib[VARYING_SLOT_POS][0];
line.y1 = v1->attrib[VARYING_SLOT_POS][1];
line.dx = line.x1 - line.x0;
line.dy = line.y1 - line.y0;
line.len = sqrtf(line.dx * line.dx + line.dy * line.dy);
line.halfWidth = 0.5F * CLAMP(ctx->Line.Width,
ctx->Const.MinLineWidthAA,
ctx->Const.MaxLineWidthAA);
if (line.len == 0.0F || IS_INF_OR_NAN(line.len))
return;
INIT_SPAN(line.span, GL_LINE);
line.span.arrayMask = SPAN_XY | SPAN_COVERAGE;
line.span.facing = swrast->PointLineFacing;
line.xAdj = line.dx / line.len * line.halfWidth;
line.yAdj = line.dy / line.len * line.halfWidth;
#ifdef DO_Z
line.span.arrayMask |= SPAN_Z;
compute_plane(line.x0, line.y0, line.x1, line.y1,
v0->attrib[VARYING_SLOT_POS][2], v1->attrib[VARYING_SLOT_POS][2], line.zPlane);
#endif
line.span.arrayMask |= SPAN_RGBA;
if (ctx->Light.ShadeModel == GL_SMOOTH) {
compute_plane(line.x0, line.y0, line.x1, line.y1,
v0->color[RCOMP], v1->color[RCOMP], line.rPlane);
compute_plane(line.x0, line.y0, line.x1, line.y1,
v0->color[GCOMP], v1->color[GCOMP], line.gPlane);
compute_plane(line.x0, line.y0, line.x1, line.y1,
v0->color[BCOMP], v1->color[BCOMP], line.bPlane);
compute_plane(line.x0, line.y0, line.x1, line.y1,
v0->color[ACOMP], v1->color[ACOMP], line.aPlane);
}
else {
constant_plane(v1->color[RCOMP], line.rPlane);
constant_plane(v1->color[GCOMP], line.gPlane);
constant_plane(v1->color[BCOMP], line.bPlane);
constant_plane(v1->color[ACOMP], line.aPlane);
}
#if defined(DO_ATTRIBS)
{
const GLfloat invW0 = v0->attrib[VARYING_SLOT_POS][3];
const GLfloat invW1 = v1->attrib[VARYING_SLOT_POS][3];
line.span.arrayMask |= SPAN_LAMBDA;
compute_plane(line.x0, line.y0, line.x1, line.y1, invW0, invW1, line.wPlane);
ATTRIB_LOOP_BEGIN
GLuint c;
if (swrast->_InterpMode[attr] == GL_FLAT) {
for (c = 0; c < 4; c++) {
constant_plane(v1->attrib[attr][c], line.attrPlane[attr][c]);
}
}
else {
for (c = 0; c < 4; c++) {
const GLfloat a0 = v0->attrib[attr][c] * invW0;
const GLfloat a1 = v1->attrib[attr][c] * invW1;
compute_plane(line.x0, line.y0, line.x1, line.y1, a0, a1,
line.attrPlane[attr][c]);
}
}
line.span.arrayAttribs |= BITFIELD64_BIT(attr);
if (attr >= VARYING_SLOT_TEX0 && attr < VARYING_SLOT_VAR0) {
const GLuint u = attr - VARYING_SLOT_TEX0;
const struct gl_texture_object *obj = ctx->Texture.Unit[u]._Current;
const struct gl_texture_image *texImage =
_mesa_base_tex_image(obj);
line.texWidth[attr] = (GLfloat) texImage->Width;
line.texHeight[attr] = (GLfloat) texImage->Height;
}
ATTRIB_LOOP_END
}
#endif
tStart = tEnd = 0.0;
inSegment = GL_FALSE;
iLen = (GLint) line.len;
if (ctx->Line.StippleFlag) {
for (i = 0; i < iLen; i++) {
const GLuint bit = (swrast->StippleCounter / ctx->Line.StippleFactor) & 0xf;
if ((1 << bit) & ctx->Line.StipplePattern) {
/* stipple bit is on */
const GLfloat t = (GLfloat) i / (GLfloat) line.len;
if (!inSegment) {
/* start new segment */
inSegment = GL_TRUE;
tStart = t;
}
else {
/* still in the segment, extend it */
tEnd = t;
}
}
else {
/* stipple bit is off */
if (inSegment && (tEnd > tStart)) {
/* draw the segment */
segment(ctx, &line, NAME(plot), tStart, tEnd);
inSegment = GL_FALSE;
}
else {
/* still between segments, do nothing */
}
}
swrast->StippleCounter++;
}
if (inSegment) {
/* draw the final segment of the line */
segment(ctx, &line, NAME(plot), tStart, 1.0F);
}
}
else {
/* non-stippled */
segment(ctx, &line, NAME(plot), 0.0, 1.0);
}
_swrast_write_rgba_span(ctx, &(line.span));
}
#undef DO_Z
#undef DO_ATTRIBS
#undef NAME