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Add correction funtion

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This commit is contained in:
Miloslav Číž 2019-06-11 15:37:40 +02:00
parent 4c042bd5fa
commit 3a29d4c679
2 changed files with 30 additions and 4 deletions
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4
programs/demo.c
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@ -11,7 +11,7 @@
#define S3L_FLAT 0
#define S3L_STRICT_NEAR_CULLING 0
#define S3L_PERSPECTIVE_CORRECTION 1
#define S3L_PERSPECTIVE_CORRECTION 2
#define S3L_SORT 2
#define S3L_STENCIL_BUFFER 1
#define S3L_Z_BUFFER 0
@ -80,6 +80,8 @@ void drawPixel(S3L_PixelInfo *p)
{
/*
S3L_correctBarycentricCoords(p->barycentric);
if (p->barycentric[0] < 0 || p->barycentric[0] > 512)
printf("%d %d %d\n",p->barycentric[0],p->barycentric[1],p->barycentric[2]);

30
small3dlib.h
View file

@ -448,9 +448,11 @@ typedef struct
triangle and interpolate values between it's
three points. Each one goes from 0 to
S3L_FRACTIONS_PER_UNIT (inclidung), but due to
rounding error may fall outside this range. The
sum of the three coordinates will always be
exactly S3L_FRACTIONS_PER_UNIT. */
rounding error may fall outside this range (you
can use S3L_correctBarycentricCoords to fix this
for the price of some performance). The sum of
the three coordinates will always be exactly
S3L_FRACTIONS_PER_UNIT. */
S3L_Index triangleIndex; ///< Triangle index.
S3L_Index modelIndex;
S3L_Unit depth; ///< Depth (only if depth is turned on).
@ -466,6 +468,12 @@ typedef struct
static inline void S3L_initPixelInfo(S3L_PixelInfo *p);
/** Corrects barycentric coordinates so that they exactly meet the defined
conditions (each fall into <0,S3L_FRACTIONS_PER_UNIT>, sum =
S3L_FRACTIONS_PER_UNIT). Note that doing this per-pixel can slow the program
down significantly. */
static inline void S3LcorrectBarycentricCoords(S3L_Unit barycentric[3]);
// general helper functions
static inline S3L_Unit S3L_abs(S3L_Unit value);
static inline S3L_Unit S3L_min(S3L_Unit v1, S3L_Unit v2);
@ -1138,6 +1146,22 @@ S3L_Unit S3L_cos(S3L_Unit x)
return S3L_sin(x - S3L_FRACTIONS_PER_UNIT / 4);
}
void S3L_correctBarycentricCoords(S3L_Unit barycentric[3])
{
barycentric[0] = S3L_clamp(barycentric[0],0,S3L_FRACTIONS_PER_UNIT);
barycentric[1] = S3L_clamp(barycentric[1],0,S3L_FRACTIONS_PER_UNIT);
S3L_Unit d = S3L_FRACTIONS_PER_UNIT - barycentric[0] - barycentric[1];
if (d < 0)
{
barycentric[0] += d;
barycentric[2] = 0;
}
else
barycentric[2] = d;
}
void S3L_makeTranslationMat(
S3L_Unit offsetX,
S3L_Unit offsetY,