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[dense] Add optimization for division 

* src/dense/ftdense.c: FT_UDIV, FT_UDIVPREP macros taken from smooth
rasterizer, help optimize fixed-point division
This commit is contained in:
Anurag Thakur 2022-11-19 13:22:15 +05:30
parent 668bc29ff0
commit 724e81ef5b
1 changed files with 18 additions and 6 deletions
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24
src/dense/ftdense.c
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@ -41,6 +41,11 @@
#define FT_MAX( a, b ) ( (a) > (b) ? (a) : (b) )
#define FT_ABS( a ) ( (a) < 0 ? -(a) : (a) )
// TODO: Fix types
#define FT_UDIVPREP( c, b ) \
FT26D6 b ## _r = c ? (FT26D6)0xFFFFFFFF / ( b ) : 0
#define FT_UDIV( a, b ) \
(FT26D6)( ( (FT26D6)( a ) * (FT26D6)( b ## _r ) ) >> 32 )
typedef struct dense_TRaster_
{
@ -114,6 +119,10 @@ dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
deltax = to_x - from_x;
deltay = to_y - from_y;
FT_UDIVPREP(from_x != to_x, deltax);
FT_UDIVPREP(from_y != to_y, deltay);
if ( from_y < 0 )
{
from_x -= from_y * deltax/deltay;
@ -164,7 +173,7 @@ dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
{
int linestart = y * worker->m_w;
FT26D6 dy = FT_MIN( (y + 1)<<6, to_y ) - FT_MAX( y<<6, from_y );
FT26D6 xnext = x + dy * deltax/deltay;
FT26D6 xnext = x + FT_UDIV((dy*deltax), deltay);
FT26D6 d = dy * dir;
FT26D6 x0, x1;
@ -197,13 +206,16 @@ dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
{
FT26D6 oneOverS = x1 - x0;
FT_UDIVPREP(x1 != x0, oneOverS);
FT26D6 x0f = x0 - x0floor;
FT26D6 oneMinusX0f = (1<<6) - x0f;
FT26D6 a0 = ((oneMinusX0f * oneMinusX0f) >> 1) / oneOverS;
FT26D6 a0 = FT_UDIV(((oneMinusX0f * oneMinusX0f) >> 1), oneOverS);
FT26D6 x1f = x1 - x1ceil + (1<<6);
FT26D6 am = ((x1f * x1f) >> 1) / oneOverS;
FT26D6 am = FT_UDIV(((x1f * x1f) >> 1) , oneOverS);
m_a[linestart + x0i] += d * a0;
@ -211,15 +223,15 @@ dense_render_line( dense_worker* worker, FT_Pos tox, FT_Pos toy )
m_a[linestart + ( x0i + 1 )] += d * ( (1<<6) - a0 - am );
else
{
FT26D6 a1 = (((1<<6) + (1<<5) - x0f) << 6) / oneOverS;
FT26D6 a1 = FT_UDIV((((1<<6) + (1<<5) - x0f) << 6) , oneOverS);
m_a[linestart + ( x0i + 1 )] += d * ( a1 - a0 );
FT26D6 dTimesS = (d << 12) / oneOverS;
FT26D6 dTimesS = FT_UDIV((d << 12) , oneOverS);
for ( FT26D6 xi = x0i + 2; xi < x1i - 1; xi++ )
m_a[linestart + xi] += dTimesS;
FT26D6 a2 = a1 + (( x1i - x0i - 3 )<<12)/oneOverS;
FT26D6 a2 = a1 + FT_UDIV((( x1i - x0i - 3 )<<12),oneOverS);
m_a[linestart + ( x1i - 1 )] += d * ( (1<<6) - a2 - am );
}
m_a[linestart + x1i] += d * am;