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Start implementing new raster. rules

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This commit is contained in:
Miloslav Číž 2019-05-04 03:44:43 +02:00
parent 8c4809e9d9
commit e5425af9ed
1 changed files with 9 additions and 8 deletions
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17
s3l.h
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@ -792,8 +792,9 @@ void S3L_drawTriangle(
v - which side (l or r) v - which side (l or r)
p1 - point from (t, l or r) p1 - point from (t, l or r)
p2 - point to (t, l or r) p2 - point to (t, l or r)
down - whether going top-down or bottom-up */ down - whether the side coordinate goes top-down or vice versa
#define initSide(v,p1,p2,down)\ shift - initial shift of the line, to rasterize pix. centers */
#define initSide(v,p1,p2,down,shift)\
v##X = p1##PointX;\ v##X = p1##PointX;\
v##Dx = p2##PointX - p1##PointX;\ v##Dx = p2##PointX - p1##PointX;\
v##Dy = p2##PointY - p1##PointY;\ v##Dy = p2##PointY - p1##PointY;\
@ -806,7 +807,7 @@ void S3L_drawTriangle(
}\ }\
helperDxAbs = S3L_abs(v##Dx);\ helperDxAbs = S3L_abs(v##Dx);\
v##Inc = v##Dx >= 0 ? 1 : -1;\ v##Inc = v##Dx >= 0 ? 1 : -1;\
v##Err = 2 * helperDxAbs - v##Dy;\ v##Err = (2 + shift) * helperDxAbs - v##Dy;\
v##ErrAdd = 2 * helperDxAbs;\ v##ErrAdd = 2 * helperDxAbs;\
v##ErrSub = 2 * v##Dy;\ v##ErrSub = 2 * v##Dy;\
v##ErrSub = v##ErrSub != 0 ? v##ErrSub : 1; /* don't allow 0, could lead v##ErrSub = v##ErrSub != 0 ? v##ErrSub : 1; /* don't allow 0, could lead
@ -820,8 +821,8 @@ void S3L_drawTriangle(
}\ }\
s##Err += s##ErrAdd; s##Err += s##ErrAdd;
initSide(r,t,r,1) initSide(r,t,r,1,-1)
initSide(l,t,l,1) initSide(l,t,l,1,1)
while (currentY <= endY) // draw the triangle from top to bottom while (currentY <= endY) // draw the triangle from top to bottom
{ {
@ -829,7 +830,7 @@ void S3L_drawTriangle(
{ // then reinit one side { // then reinit one side
if (splitOnLeft) if (splitOnLeft)
{ {
initSide(l,l,r,0); initSide(l,l,r,0,1);
S3L_Unit *tmp = barycentric0; S3L_Unit *tmp = barycentric0;
barycentric0 = barycentric2; barycentric0 = barycentric2;
@ -840,7 +841,7 @@ void S3L_drawTriangle(
} }
else else
{ {
initSide(r,r,l,0); initSide(r,r,l,0,-1);
S3L_Unit *tmp = barycentric1; S3L_Unit *tmp = barycentric1;
barycentric1 = barycentric2; barycentric1 = barycentric2;
@ -861,7 +862,7 @@ void S3L_drawTriangle(
S3L_Unit t1 = 0; S3L_Unit t1 = 0;
S3L_Unit t2 = tMax; S3L_Unit t2 = tMax;
for (S3L_ScreenCoord x = lX; x <= rX; ++x) for (S3L_ScreenCoord x = lX; x < rX; ++x)
{ {
*barycentric0 = S3L_interpolateFrom0(rSideUnitPos,t1,tMax); *barycentric0 = S3L_interpolateFrom0(rSideUnitPos,t1,tMax);
*barycentric1 = S3L_interpolateFrom0(lSideUnitPos,t2,tMax); *barycentric1 = S3L_interpolateFrom0(lSideUnitPos,t2,tMax);