nir: add a pass to clamp gl_PointSize to a range

The OpenGL and OpenGL ES specs require that implementations clamp the
value of gl_PointSize to an implementation-depedent range. This pass
is useful for any GPU hardware that doesn't do this automatically
for either one or both sides of the range, such as V3D.

v2:
 - Turn into a generic NIR pass (Eric).
 - Make the pass work before lower I/O so we can use the deref variable
   to inspect if we are writing to gl_PointSize (Eric).
 - Make the pass take the range to clamp as parameter and allow it
   to clamp to both sides of the range or just one side.
 - Make the pass report progress.

v3:
 - Fix copyright header (Eric)
 - use fmin/fmax instead of bcsel to clamp (Eric)

Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 314b696f738..09a3be5527e 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -3886,6 +3886,8 @@ bool nir_lower_doubles(nir_shader *shader, const nir_shader *softfp64,
                        nir_lower_doubles_options options);
 bool nir_lower_pack(nir_shader *shader);
 
+bool nir_lower_point_size(nir_shader *shader, float min, float max);
+
 typedef enum {
    nir_lower_interpolation_at_sample = (1 << 1),
    nir_lower_interpolation_at_offset = (1 << 2),