experiment with texture filtering

This commit is contained in:
David Rose 2008-05-05 21:02:21 +00:00
parent a88673a24a
commit b226cf6f5d
4 changed files with 71 additions and 25 deletions

View File

@ -35,10 +35,10 @@ void gl_transform_to_viewport(GLContext *c,GLVertex *v)
/* texture */
if (c->texture_2d_enabled) {
v->zp.s=(int)(v->tex_coord.X * (ZB_POINT_S_MAX - ZB_POINT_S_MIN)
+ ZB_POINT_S_MIN);
v->zp.t=(int)(v->tex_coord.Y * (ZB_POINT_T_MAX - ZB_POINT_T_MIN)
+ ZB_POINT_T_MIN);
v->zp.s=(int)(v->tex_coord.X * (ZB_POINT_ST_MAX - ZB_POINT_ST_MIN)
+ ZB_POINT_ST_MIN);
v->zp.t=(int)(v->tex_coord.Y * (ZB_POINT_ST_MAX - ZB_POINT_ST_MIN)
+ ZB_POINT_ST_MIN);
}
}

View File

@ -340,3 +340,36 @@ void ZB_clear_viewport(ZBuffer * zb, int clear_z, int z,
}
}
}
#define ZB_ST_FRAC_HIGH (1 << ZB_POINT_ST_FRAC_BITS)
#define ZB_ST_FRAC_MASK (ZB_ST_FRAC_HIGH - 1)
PIXEL lookup_texture_bilinear(PIXEL *texture, int s, int t)
{
PIXEL p1, p2, p3, p4;
int sf, tf;
int r, g, b, a;
p1 = ZB_LOOKUP_TEXTURE_NEAREST(texture, s, t);
p2 = ZB_LOOKUP_TEXTURE_NEAREST(texture, s + ZB_ST_FRAC_HIGH, t);
sf = s & ZB_ST_FRAC_MASK;
p3 = ZB_LOOKUP_TEXTURE_NEAREST(texture, s, t + ZB_ST_FRAC_HIGH);
p4 = ZB_LOOKUP_TEXTURE_NEAREST(texture, s + ZB_ST_FRAC_HIGH, t + ZB_ST_FRAC_HIGH);
tf = t & ZB_ST_FRAC_MASK;
r = (((PIXEL_R(p4) * sf + PIXEL_R(p3) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * tf +
((PIXEL_R(p2) * sf + PIXEL_R(p1) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * (ZB_ST_FRAC_HIGH - tf)) >> ZB_POINT_ST_FRAC_BITS;
g = (((PIXEL_G(p4) * sf + PIXEL_G(p3) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * tf +
((PIXEL_G(p2) * sf + PIXEL_G(p1) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * (ZB_ST_FRAC_HIGH - tf)) >> ZB_POINT_ST_FRAC_BITS;
b = (((PIXEL_B(p4) * sf + PIXEL_B(p3) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * tf +
((PIXEL_B(p2) * sf + PIXEL_B(p1) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * (ZB_ST_FRAC_HIGH - tf)) >> ZB_POINT_ST_FRAC_BITS;
a = (((PIXEL_A(p4) * sf + PIXEL_A(p3) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * tf +
((PIXEL_A(p2) * sf + PIXEL_A(p1) * (ZB_ST_FRAC_HIGH - sf)) >> ZB_POINT_ST_FRAC_BITS) * (ZB_ST_FRAC_HIGH - tf)) >> ZB_POINT_ST_FRAC_BITS;
return RGBA_TO_PIXEL(r, g, b, a);
}

View File

@ -18,25 +18,36 @@
/* The number of fractional bits below the S and T texture coords.
The more we have, the more precise the texel calculation will be
when we zoom into small details of a texture; but the greater
chance we'll overflow our 32-bit integer if the T texcoord gets
large. */
#define ZB_POINT_ST_FRAC_BITS 10
chance we might overflow our 32-bit integer. */
#define ZB_POINT_ST_FRAC_BITS 12
/* Various parameters and accessors based on the above bits. */
#define ZB_POINT_S_LOW ZB_POINT_ST_FRAC_BITS
#define ZB_POINT_S_MIN 0
#define ZB_POINT_S_MAX (1 << (ZB_POINT_ST_BITS + ZB_POINT_S_LOW))
#define ZB_POINT_S_MASK ((1 << (ZB_POINT_ST_BITS + ZB_POINT_S_LOW)) - (1 << ZB_POINT_S_LOW))
#define ZB_POINT_ST_MIN 0
#define ZB_POINT_ST_MAX (1 << (ZB_POINT_ST_BITS + ZB_POINT_ST_FRAC_BITS))
#define ZB_POINT_ST_MASK ((1 << (ZB_POINT_ST_BITS + ZB_POINT_ST_FRAC_BITS)) - (1 << ZB_POINT_ST_FRAC_BITS))
#define ZB_POINT_T_LOW (ZB_POINT_ST_BITS + ZB_POINT_S_LOW)
#define ZB_POINT_T_MIN 0
#define ZB_POINT_T_MAX (1 << (ZB_POINT_ST_BITS + ZB_POINT_T_LOW))
#define ZB_POINT_T_MASK ((1 << (ZB_POINT_ST_BITS + ZB_POINT_T_LOW)) - (1 << ZB_POINT_T_LOW))
// Returns the index within a 256x256 texture for the given (s, t)
// texel.
/* Returns the index within a 256x256 texture for the given (s, t)
texel. */
#define ZB_TEXEL(s, t) \
((((t) & ZB_POINT_T_MASK) | ((s) & ZB_POINT_S_MASK)) >> ZB_POINT_ST_FRAC_BITS)
((((t) & ZB_POINT_ST_MASK) >> (ZB_POINT_ST_FRAC_BITS - ZB_POINT_ST_BITS)) | \
(((s) & ZB_POINT_ST_MASK) >> ZB_POINT_ST_FRAC_BITS))
#define ZB_LOOKUP_TEXTURE_NEAREST(texture, s, t) \
(texture)[ZB_TEXEL(s, t)]
#if 1
/* Use no texture filtering by default. It's faster, even though it
looks terrible. */
#define ZB_LOOKUP_TEXTURE(texture, s, t) \
ZB_LOOKUP_TEXTURE_NEAREST(texture, s, t)
#else
/* Experiment with bilinear filtering. Looks great, but seems to run
about 25% slower. */
#define ZB_LOOKUP_TEXTURE(texture, s, t) \
lookup_texture_bilinear((texture), (s), (t))
#endif
#define ZB_POINT_RED_MIN 0x0000
#define ZB_POINT_RED_MAX 0xffff
@ -122,6 +133,8 @@ void ZB_clear_viewport(ZBuffer * zb, int clear_z, int z,
int clear_color, int r, int g, int b, int a,
int xmin, int ymin, int xsize, int ysize);
PIXEL lookup_texture_bilinear(PIXEL *texture, int s, int t);
/* linesize is in BYTES */
void ZB_copyFrameBuffer(ZBuffer *zb,void *buf,int linesize);

View File

@ -82,7 +82,7 @@ void FNAME(ZB_fillTriangleMapping) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
if (ACMP(zb, PIXEL_A(tmp))) { \
STORE_PIX(pp[_a], tmp, PIXEL_R(tmp), PIXEL_G(tmp), PIXEL_B(tmp), PIXEL_A(tmp)); \
STORE_Z(pz[_a], zz); \
@ -118,7 +118,7 @@ void FNAME(ZB_fillTriangleMappingFlat) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
int a = oa * PIXEL_A(tmp) >> 16; \
if (ACMP(zb, a)) { \
STORE_PIX(pp[_a], \
@ -159,7 +159,7 @@ void FNAME(ZB_fillTriangleMappingSmooth) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
int a = oa1 * PIXEL_A(tmp) >> 16; \
if (ACMP(zb, a)) { \
STORE_PIX(pp[_a], \
@ -216,7 +216,7 @@ void FNAME(ZB_fillTriangleMappingPerspective) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
if (ACMP(zb, PIXEL_A(tmp))) { \
STORE_PIX(pp[_a], tmp, PIXEL_R(tmp), PIXEL_G(tmp), PIXEL_B(tmp), PIXEL_A(tmp)); \
STORE_Z(pz[_a], zz); \
@ -321,7 +321,7 @@ void FNAME(ZB_fillTriangleMappingPerspectiveFlat) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
int a = oa * PIXEL_A(tmp) >> 16; \
if (ACMP(zb, a)) { \
STORE_PIX(pp[_a], \
@ -434,7 +434,7 @@ void FNAME(ZB_fillTriangleMappingPerspectiveSmooth) (ZBuffer *zb,
{ \
zz=z >> ZB_POINT_Z_FRAC_BITS; \
if (ZCMP(pz[_a], zz)) { \
tmp = texture[ZB_TEXEL(s, t)]; \
tmp = ZB_LOOKUP_TEXTURE(texture, s, t); \
int a = oa1 * PIXEL_A(tmp) >> 16; \
if (ACMP(zb, a)) { \
STORE_PIX(pp[_a], \