mirror of
https://git.coom.tech/drummyfish/small3dlib.git
synced 2024-11-23 20:59:58 +01:00
Fix persp. corr (ugly)
This commit is contained in:
Miloslav Číž
parent
a7237a2aee
commit
625d2436eb
2 changed files with 45 additions and 149 deletions
190
small3dlib.h
190
small3dlib.h
|
|
@ -1077,106 +1077,6 @@ typedef struct
|
|||
#define S3L_stepFastLerp(state)\
|
||||
state.valueScaled += state.stepScaled
|
||||
|
||||
typedef struct
|
||||
{
|
||||
S3L_ScreenCoord p0[2]; ///< 2D coordinates of the 1st point projection
|
||||
S3L_ScreenCoord p1[2]; ///< 2D coordinates of the 2nd point projection
|
||||
|
||||
S3L_Unit a[3]; ///< 3D coordinates of the 1st projected point of the line
|
||||
S3L_Unit b[3]; ///< 3D coordinates of the 2nd projected point of the line
|
||||
S3L_Unit pointDifference[3]; ///< [bx - ax, by - ay, bz - cz]
|
||||
|
||||
S3L_ScreenCoord c[2]; /**< helper point to for a plane for the intersection
|
||||
with line */
|
||||
|
||||
S3L_Unit fcx; ///< precomputed helper product
|
||||
S3L_Unit fcy; ///< precomputed helper product
|
||||
|
||||
S3L_Unit focalLength;
|
||||
} S3L_PerspectiveCorrectionState; ///< State for computing persp. correction.
|
||||
|
||||
/**
|
||||
Initializes the state of perspective correction along a line. The correction
|
||||
itself is then done using S3L_correctPerspective function, using the state.
|
||||
*/
|
||||
void S3L_initPerspectiveCorrectionState(
|
||||
S3L_ScreenCoord x0,
|
||||
S3L_ScreenCoord y0,
|
||||
S3L_Unit depth0,
|
||||
S3L_ScreenCoord x1,
|
||||
S3L_ScreenCoord y1,
|
||||
S3L_Unit depth1,
|
||||
S3L_Unit focalLength,
|
||||
S3L_PerspectiveCorrectionState *state)
|
||||
{
|
||||
state->focalLength = focalLength;
|
||||
|
||||
state->p0[0] = x0;
|
||||
state->p0[1] = y0;
|
||||
|
||||
state->p1[0] = x1;
|
||||
state->p1[1] = y1;
|
||||
|
||||
state->a[0] = (x0 * (depth0 + focalLength)) / focalLength;
|
||||
state->a[1] = (y0 * (depth0 + focalLength)) / focalLength;
|
||||
state->a[2] = depth0;
|
||||
|
||||
state->b[0] = (x1 * (depth1 + focalLength)) / focalLength;
|
||||
state->b[1] = (y1 * (depth1 + focalLength)) / focalLength;
|
||||
state->b[2] = depth1;
|
||||
|
||||
state->pointDifference[0] = state->b[0] - state->a[0];
|
||||
state->pointDifference[1] = state->b[1] - state->a[1];
|
||||
state->pointDifference[2] = state->b[2] - state->a[2];
|
||||
|
||||
state->c[0] = x1 + y1 - y0;
|
||||
state->c[1] = y1 - x1 + x0;
|
||||
|
||||
state->fcx = focalLength * state->c[0];
|
||||
state->fcy = focalLength * state->c[1];
|
||||
}
|
||||
|
||||
S3L_Unit S3L_correctPerspective(
|
||||
S3L_Unit interpolationParameter, S3L_PerspectiveCorrectionState *state)
|
||||
{
|
||||
S3L_Unit p[2]; // lin. interpolated position between the projections
|
||||
|
||||
// TODO: perhaps this could be interpolated faster by stepping?
|
||||
p[0] =
|
||||
S3L_interpolateByUnit(state->p0[0],state->p1[0],interpolationParameter);
|
||||
|
||||
p[1] =
|
||||
S3L_interpolateByUnit(state->p0[1],state->p1[1],interpolationParameter);
|
||||
|
||||
S3L_Unit a, b, c, d; // plane coeficients
|
||||
|
||||
a = state->focalLength * p[1] - state->fcy;
|
||||
b = state->fcx - state->focalLength * p[0];
|
||||
c = p[0] * state->c[1] - p[1] * state->c[0];
|
||||
d = state->focalLength * c;
|
||||
|
||||
a >>= 4; // TODO: this sometimes prevents overflow, but should be solved better!
|
||||
b >>= 4;
|
||||
c >>= 4;
|
||||
d >>= 4;
|
||||
|
||||
S3L_Unit result =
|
||||
(
|
||||
- a * state->a[0] - b * state->a[1] - c * state->a[2] - d
|
||||
)
|
||||
/
|
||||
S3L_nonZero(
|
||||
(
|
||||
a * state->pointDifference[0] +
|
||||
b * state->pointDifference[1] +
|
||||
c * state->pointDifference[2]
|
||||
) / S3L_FRACTIONS_PER_UNIT
|
||||
);
|
||||
|
||||
return result < 0 ? 0 :
|
||||
(result > S3L_FRACTIONS_PER_UNIT ? S3L_FRACTIONS_PER_UNIT : result);
|
||||
}
|
||||
|
||||
static inline S3L_Unit S3L_interpolateBarycentric(
|
||||
S3L_Unit value0,
|
||||
S3L_Unit value1,
|
||||
|
|
@ -1475,22 +1375,23 @@ void S3L_drawTriangle(
|
|||
initSide(r,t,r,1)
|
||||
initSide(l,t,l,1)
|
||||
|
||||
#define initPC(f,t,pc)\
|
||||
S3L_initPerspectiveCorrectionState(\
|
||||
f##PointPP->x,\
|
||||
f##PointPP->y,\
|
||||
f##PointPP->z,\
|
||||
t##PointPP->x,\
|
||||
t##PointPP->y,\
|
||||
t##PointPP->z,\
|
||||
camera->focalLength,\
|
||||
&pc##PC);
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
S3L_PerspectiveCorrectionState lPC, rPC, rowPC;
|
||||
S3L_Unit tPointRecipZ, lPointRecipZ, rPointRecipZ,
|
||||
lRecip0, lRecip1, rRecip0, rRecip1;
|
||||
|
||||
initPC(t,l,l)
|
||||
initPC(t,r,r)
|
||||
tPointRecipZ = (S3L_FRACTIONS_PER_UNIT * S3L_FRACTIONS_PER_UNIT)
|
||||
/ S3L_nonZero(tPointPP->z);
|
||||
|
||||
lPointRecipZ = (S3L_FRACTIONS_PER_UNIT * S3L_FRACTIONS_PER_UNIT)
|
||||
/ S3L_nonZero(lPointPP->z);
|
||||
|
||||
rPointRecipZ = (S3L_FRACTIONS_PER_UNIT * S3L_FRACTIONS_PER_UNIT)
|
||||
/ S3L_nonZero(rPointPP->z);
|
||||
|
||||
lRecip0 = tPointRecipZ;
|
||||
lRecip1 = lPointRecipZ;
|
||||
rRecip0 = tPointRecipZ;
|
||||
rRecip1 = rPointRecipZ;
|
||||
#endif
|
||||
|
||||
// clip to the screen in y dimension:
|
||||
|
|
@ -1519,20 +1420,22 @@ void S3L_drawTriangle(
|
|||
{
|
||||
initSide(l,l,r,0);
|
||||
manageSplit(0,2,r)
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
initPC(r,l,l)
|
||||
initPC(r,t,r)
|
||||
lRecip0 = rPointRecipZ;
|
||||
lRecip1 = lPointRecipZ;
|
||||
rRecip0 = rPointRecipZ;
|
||||
rRecip1 = tPointRecipZ ;
|
||||
#endif
|
||||
}
|
||||
else
|
||||
{
|
||||
initSide(r,r,l,0);
|
||||
manageSplit(1,2,l)
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
initPC(l,r,r)
|
||||
initPC(l,t,l)
|
||||
rRecip0 = lPointRecipZ;
|
||||
rRecip1 = rPointRecipZ;
|
||||
lRecip0 = lPointRecipZ;
|
||||
lRecip1 = tPointRecipZ;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
|
@ -1552,26 +1455,16 @@ void S3L_drawTriangle(
|
|||
S3L_Unit rowLength = S3L_nonZero(rX - lX - 1); // prevent zero div
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
S3L_Unit
|
||||
lDepth, rDepth,
|
||||
lT, rT; // perspective-corrected position along either side
|
||||
S3L_Unit lOverZ, lRecipZ, rOverZ, rRecipZ, lT, rT;
|
||||
|
||||
lT = S3L_correctPerspective(S3L_getFastLerpValue(lSideFLS),&lPC);
|
||||
rT = S3L_correctPerspective(S3L_getFastLerpValue(rSideFLS),&rPC);
|
||||
lT = S3L_getFastLerpValue(lSideFLS);
|
||||
rT = S3L_getFastLerpValue(rSideFLS);
|
||||
|
||||
lDepth = S3L_interpolateByUnit(lPC.a[2],lPC.b[2],lT);
|
||||
rDepth = S3L_interpolateByUnit(rPC.a[2],rPC.b[2],rT);
|
||||
lOverZ = S3L_interpolateByUnitFrom0(lRecip1,lT);
|
||||
lRecipZ = S3L_interpolateByUnit(lRecip0,lRecip1,lT);
|
||||
|
||||
S3L_initPerspectiveCorrectionState(
|
||||
S3L_interpolateByUnit(lPC.a[0],lPC.b[0],lT),
|
||||
S3L_interpolateByUnit(lPC.a[1],lPC.b[1],lT),
|
||||
lDepth,
|
||||
S3L_interpolateByUnit(rPC.a[0],rPC.b[0],rT),
|
||||
S3L_interpolateByUnit(rPC.a[1],rPC.b[1],rT),
|
||||
rDepth,
|
||||
camera->focalLength,
|
||||
&rowPC
|
||||
);
|
||||
rOverZ = S3L_interpolateByUnitFrom0(rRecip1,rT);
|
||||
rRecipZ = S3L_interpolateByUnit(rRecip0,rRecip1,rT);
|
||||
#else
|
||||
S3L_FastLerpState b0FLS, b1FLS;
|
||||
|
||||
|
|
@ -1619,16 +1512,8 @@ void S3L_drawTriangle(
|
|||
#endif
|
||||
p.x = x;
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
S3L_Unit rowT =
|
||||
S3L_correctPerspective(S3L_interpolateFrom0(S3L_FRACTIONS_PER_UNIT,
|
||||
x - lX,rowLength),&rowPC);
|
||||
#endif
|
||||
|
||||
#if S3L_COMPUTE_DEPTH
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
p.depth = S3L_interpolateByUnit(lDepth,rDepth,rowT);
|
||||
#else
|
||||
#if S3L_PERSPECTIVE_CORRECTION != S3L_PC_FULL
|
||||
p.depth = S3L_getFastLerpValue(depthFLS);
|
||||
S3L_stepFastLerp(depthFLS);
|
||||
#endif
|
||||
|
|
@ -1645,11 +1530,20 @@ void S3L_drawTriangle(
|
|||
#endif
|
||||
|
||||
#if S3L_PERSPECTIVE_CORRECTION == S3L_PC_FULL
|
||||
p.depth = (S3L_FRACTIONS_PER_UNIT * S3L_FRACTIONS_PER_UNIT) /
|
||||
S3L_nonZero(S3L_interpolate(lRecipZ,rRecipZ,x - lX,rX - lX));
|
||||
|
||||
*barycentric0 =
|
||||
S3L_interpolateByUnitFrom0(rT,rowT);
|
||||
(
|
||||
S3L_interpolate(0,rOverZ,x - lX,rX - lX)
|
||||
* p.depth
|
||||
) / S3L_FRACTIONS_PER_UNIT;
|
||||
|
||||
*barycentric1 =
|
||||
S3L_interpolateByUnitFrom0(lT,S3L_FRACTIONS_PER_UNIT - rowT);
|
||||
(
|
||||
S3L_interpolate(lOverZ,0,x - lX,rX - lX)
|
||||
* p.depth
|
||||
) / S3L_FRACTIONS_PER_UNIT;
|
||||
#else
|
||||
*barycentric0 = S3L_getFastLerpValue(b0FLS);
|
||||
*barycentric1 = S3L_getFastLerpValue(b1FLS);
|
||||
|
|
|
|||
|
|
@ -7,7 +7,9 @@
|
|||
#include <stdio.h>
|
||||
#include <math.h>
|
||||
|
||||
#define S3L_PRESET_HIGHEST_QUALITY
|
||||
//#define S3L_PRESET_HIGHEST_QUALITY
|
||||
|
||||
#define S3L_PERSPECTIVE_CORRECTION 1
|
||||
|
||||
#define S3L_PIXEL_FUNCTION drawPixel
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue