diff options
| -rw-r--r-- | src/gallium/drivers/softpipe/sp_tex_sample.c | 99 |
1 files changed, 71 insertions, 28 deletions
diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.c b/src/gallium/drivers/softpipe/sp_tex_sample.c index 473ec3e150a..824d8d12b02 100644 --- a/src/gallium/drivers/softpipe/sp_tex_sample.c +++ b/src/gallium/drivers/softpipe/sp_tex_sample.c @@ -1327,6 +1327,11 @@ mip_filter_linear(struct tgsi_sampler *tgsi_sampler, } +/** + * Compute nearest mipmap level from texcoords. + * Then sample the texture level for four elements of a quad. + * \param c0 the LOD bias factors, or absolute LODs (depending on control) + */ static void mip_filter_nearest(struct tgsi_sampler *tgsi_sampler, const float s[QUAD_SIZE], @@ -1563,8 +1568,8 @@ sample_compare(struct tgsi_sampler *tgsi_sampler, /** - * Compute which cube face is referenced by each texcoord and put that - * info into the sampler faces[] array. Then sample the cube faces + * Use 3D texcoords to choose a cube face, then sample the 2D cube faces. + * Put face info into the sampler faces[] array. */ static void sample_cube(struct tgsi_sampler *tgsi_sampler, @@ -1578,11 +1583,12 @@ sample_cube(struct tgsi_sampler *tgsi_sampler, struct sp_sampler_varient *samp = sp_sampler_varient(tgsi_sampler); unsigned j; float ssss[4], tttt[4]; + unsigned face; /* major axis - direction target sc tc ma - ---------- ------------------------------- --- --- --- + direction target sc tc ma + ---------- ------------------------------- --- --- --- +rx TEXTURE_CUBE_MAP_POSITIVE_X_EXT -rz -ry rx -rx TEXTURE_CUBE_MAP_NEGATIVE_X_EXT +rz -ry rx +ry TEXTURE_CUBE_MAP_POSITIVE_Y_EXT +rx +rz ry @@ -1590,56 +1596,93 @@ sample_cube(struct tgsi_sampler *tgsi_sampler, +rz TEXTURE_CUBE_MAP_POSITIVE_Z_EXT +rx -ry rz -rz TEXTURE_CUBE_MAP_NEGATIVE_Z_EXT -rx -ry rz */ - for (j = 0; j < QUAD_SIZE; j++) { - float rx = s[j]; - float ry = t[j]; - float rz = p[j]; + + /* First choose the cube face. + * Use the same cube face for all four pixels in the quad. + * + * This isn't ideal, but if we want to use a different cube face + * per pixel in the quad, we'd have to also compute the per-face + * LOD here too. That's because the four post-face-selection + * texcoords are no longer related to each other (they're + * per-face!) so we can't use subtraction to compute the partial + * deriviates to compute the LOD. Doing so (near cube edges + * anyway) gives us pretty much random values. + */ + { + /* use the average of the four pixel's texcoords to choose the face */ + const float rx = 0.25 * (s[0] + s[1] + s[2] + s[3]); + const float ry = 0.25 * (t[0] + t[1] + t[2] + t[3]); + const float rz = 0.25 * (p[0] + p[1] + p[2] + p[3]); const float arx = fabsf(rx), ary = fabsf(ry), arz = fabsf(rz); - unsigned face; - float sc, tc, ma; if (arx >= ary && arx >= arz) { if (rx >= 0.0F) { face = PIPE_TEX_FACE_POS_X; - sc = -rz; - tc = -ry; - ma = arx; } else { face = PIPE_TEX_FACE_NEG_X; - sc = rz; - tc = -ry; - ma = arx; } } else if (ary >= arx && ary >= arz) { if (ry >= 0.0F) { face = PIPE_TEX_FACE_POS_Y; - sc = rx; - tc = rz; - ma = ary; } else { face = PIPE_TEX_FACE_NEG_Y; - sc = rx; - tc = -rz; - ma = ary; } } else { if (rz > 0.0F) { face = PIPE_TEX_FACE_POS_Z; - sc = rx; - tc = -ry; - ma = arz; } else { face = PIPE_TEX_FACE_NEG_Z; - sc = -rx; - tc = -ry; - ma = arz; } } + } + + /* Now compute the 2D _face_ texture coords from the + * 3D _cube_ texture coords. + */ + for (j = 0; j < QUAD_SIZE; j++) { + const float rx = s[j], ry = t[j], rz = p[j]; + const float arx = fabsf(rx), ary = fabsf(ry), arz = fabsf(rz); + float sc, tc, ma; + + switch (face) { + case PIPE_TEX_FACE_POS_X: + sc = -rz; + tc = -ry; + ma = arx; + break; + case PIPE_TEX_FACE_NEG_X: + sc = rz; + tc = -ry; + ma = arx; + break; + case PIPE_TEX_FACE_POS_Y: + sc = rx; + tc = rz; + ma = ary; + break; + case PIPE_TEX_FACE_NEG_Y: + sc = rx; + tc = -rz; + ma = ary; + break; + case PIPE_TEX_FACE_POS_Z: + sc = rx; + tc = -ry; + ma = arz; + break; + case PIPE_TEX_FACE_NEG_Z: + sc = -rx; + tc = -ry; + ma = arz; + break; + default: + assert(0 && "bad cube face"); + } { const float ima = 1.0 / ma; |