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Update z-buffer

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Miloslav Číž 2019-06-24 00:21:14 +02:00
parent 87d7718545
commit 2ca331eb64
1 changed files with 20 additions and 2 deletions
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22
small3dlib.h
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@ -215,6 +215,11 @@ typedef uint16_t S3L_Index;
#define S3L_Z_BUFFER 0
#endif
#ifndef S3L_REDUCED_Z_BUFFER_GRANULARITY
/** For S3L_Z_BUFFER == 2 this sets the reduced z-buffer granularity. */
#define S3L_REDUCED_Z_BUFFER_GRANULARITY 5
#endif
#ifndef S3L_STENCIL_BUFFER
/** Whether to use stencil buffer for drawing -- with this a pixel that would
be resterized over an already rasterized pixel will be discarded. This is
@ -698,7 +703,8 @@ static inline void S3L_rotate2DPoint(S3L_Unit *x, S3L_Unit *y, S3L_Unit angle);
#define S3L_COMPUTE_DEPTH 1
#define S3L_MAX_DEPTH 255
uint8_t S3L_zBuffer[S3L_RESOLUTION_X * S3L_RESOLUTION_Y];
#define S3L_zBufferFormat(depth) (((depth) >> 5) & 0x000000FF)
#define S3L_zBufferFormat(depth)\
S3L_min(255,(depth) >> S3L_REDUCED_Z_BUFFER_GRANULARITY)
#endif
#if S3L_Z_BUFFER
@ -711,12 +717,24 @@ static inline int8_t S3L_zTest(
depth = S3L_zBufferFormat(depth);
if (depth < S3L_zBuffer[index])
#if S3L_Z_BUFFER == 2
#define cmp <= /* For reduced z-buffer we need equality test, because
otherwise pixels at the maximum depth (255) would never be
drawn over the background (which also has the depth of
255). */
#else
#define cmp < /* For normal z-buffer we leave out equality test to not waste
time by drawing over already drawn pixls. */
#endif
if (depth cmp S3L_zBuffer[index])
{
S3L_zBuffer[index] = depth;
return 1;
}
#undef cmp
return 0;
}
#endif