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-rw-r--r--src/gallium/drivers/softpipe/sp_tex_sample.c99
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;