[Mesa-dev] [PATCH v2 03/10] softpipe: Split compute_lambda_lod into two functions

[Krzesimir Nowak]

textureQueryLod returns a vec2 with a mipmap information and a
LOD. The latter needs to be not clamped.

v2:
  - changed the "not_clamped" part to "unclamped"
  - corrected "clamp into" to "clamp to"
  - splitted too long lines

Reviewed-by: Brian Paul <brianp at vmware.com>
---
 src/gallium/drivers/softpipe/sp_tex_sample.c | 57 +++++++++++++++++++---------
 1 file changed, 40 insertions(+), 17 deletions(-)

diff --git a/src/gallium/drivers/softpipe/sp_tex_sample.c b/src/gallium/drivers/softpipe/sp_tex_sample.c
index 19188b0..30c9cb0 100644
--- a/src/gallium/drivers/softpipe/sp_tex_sample.c
+++ b/src/gallium/drivers/softpipe/sp_tex_sample.c
@@ -1855,24 +1855,23 @@ compute_lod(const struct pipe_sampler_state *sampler,
 }
 
 
-/* Calculate level of detail for every fragment.
+/* Calculate level of detail for every fragment. The computed value is not
+ * clamped to lod_min and lod_max.
  * \param lod_in per-fragment lod_bias or explicit_lod.
  * \param lod results per-fragment lod.
  */
 static inline void
-compute_lambda_lod(struct sp_sampler_view *sp_sview,
-                   struct sp_sampler *sp_samp,
-                   const float s[TGSI_QUAD_SIZE],
-                   const float t[TGSI_QUAD_SIZE],
-                   const float p[TGSI_QUAD_SIZE],
-                   const float lod_in[TGSI_QUAD_SIZE],
-                   enum tgsi_sampler_control control,
-                   float lod[TGSI_QUAD_SIZE])
+compute_lambda_lod_unclamped(struct sp_sampler_view *sp_sview,
+                             struct sp_sampler *sp_samp,
+                             const float s[TGSI_QUAD_SIZE],
+                             const float t[TGSI_QUAD_SIZE],
+                             const float p[TGSI_QUAD_SIZE],
+                             const float lod_in[TGSI_QUAD_SIZE],
+                             enum tgsi_sampler_control control,
+                             float lod[TGSI_QUAD_SIZE])
 {
    const struct pipe_sampler_state *sampler = &sp_samp->base;
-   float lod_bias = sampler->lod_bias;
-   float min_lod = sampler->min_lod;
-   float max_lod = sampler->max_lod;
+   const float lod_bias = sampler->lod_bias;
    float lambda;
    uint i;
 
@@ -1881,24 +1880,22 @@ compute_lambda_lod(struct sp_sampler_view *sp_sview,
       /* XXX FIXME */
    case tgsi_sampler_derivs_explicit:
       lambda = sp_sview->compute_lambda(sp_sview, s, t, p) + lod_bias;
-      lod[0] = lod[1] = lod[2] = lod[3] = CLAMP(lambda, min_lod, max_lod);
+      lod[0] = lod[1] = lod[2] = lod[3] = lambda;
       break;
    case tgsi_sampler_lod_bias:
       lambda = sp_sview->compute_lambda(sp_sview, s, t, p) + lod_bias;
       for (i = 0; i < TGSI_QUAD_SIZE; i++) {
          lod[i] = lambda + lod_in[i];
-         lod[i] = CLAMP(lod[i], min_lod, max_lod);
       }
       break;
    case tgsi_sampler_lod_explicit:
       for (i = 0; i < TGSI_QUAD_SIZE; i++) {
-         lod[i] = CLAMP(lod_in[i] + lod_bias, min_lod, max_lod);
+         lod[i] = lod_in[i] + lod_bias;
       }
       break;
    case tgsi_sampler_lod_zero:
    case tgsi_sampler_gather:
-      /* this is all static state in the sampler really need clamp here? */
-      lod[0] = lod[1] = lod[2] = lod[3] = CLAMP(lod_bias, min_lod, max_lod);
+      lod[0] = lod[1] = lod[2] = lod[3] = lod_bias;
       break;
    default:
       assert(0);
@@ -1906,6 +1903,32 @@ compute_lambda_lod(struct sp_sampler_view *sp_sview,
    }
 }
 
+/* Calculate level of detail for every fragment.
+ * \param lod_in per-fragment lod_bias or explicit_lod.
+ * \param lod results per-fragment lod.
+ */
+static inline void
+compute_lambda_lod(struct sp_sampler_view *sp_sview,
+                   struct sp_sampler *sp_samp,
+                   const float s[TGSI_QUAD_SIZE],
+                   const float t[TGSI_QUAD_SIZE],
+                   const float p[TGSI_QUAD_SIZE],
+                   const float lod_in[TGSI_QUAD_SIZE],
+                   enum tgsi_sampler_control control,
+                   float lod[TGSI_QUAD_SIZE])
+{
+   const struct pipe_sampler_state *sampler = &sp_samp->base;
+   const float min_lod = sampler->min_lod;
+   const float max_lod = sampler->max_lod;
+   int i;
+
+   compute_lambda_lod_unclamped(sp_sview, sp_samp,
+                                s, t, p, lod_in, control, lod);
+   for (i = 0; i < TGSI_QUAD_SIZE; i++) {
+      lod[i] = CLAMP(lod[i], min_lod, max_lod);
+   }
+}
+
 static inline unsigned
 get_gather_component(const float lod_in[TGSI_QUAD_SIZE])
 {
-- 
2.4.3