[Mesa-dev] [PATCH] glsl: Use M_PI_* macros.

[Aaron Watry]

On Mon, Apr 7, 2014 at 12:19 PM, Matt Turner <mattst88 at gmail.com> wrote:
> Notice our multiple values for M_PI_2, which rounded ...32 up to
> ...4 and ...5.
> ---
> The float casts are ugly. I tried to define M_PI_2f using the
> preprocessor -- something like
>    #define M_PI_2f M_PI_2##f
> but no luck.
>
>  src/glsl/builtin_functions.cpp | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/src/glsl/builtin_functions.cpp b/src/glsl/builtin_functions.cpp
> index 26ea923..62bf154 100644
> --- a/src/glsl/builtin_functions.cpp
> +++ b/src/glsl/builtin_functions.cpp
> @@ -2538,11 +2538,11 @@ ir_expression *
>  builtin_builder::asin_expr(ir_variable *x)
>  {
>     return mul(sign(x),
> -              sub(imm(1.5707964f),
> +              sub(imm((float)M_PI_2),
>                    mul(sqrt(sub(imm(1.0f), abs(x))),
> -                      add(imm(1.5707964f),
> +                      add(imm((float)M_PI_2),
>                            mul(abs(x),
> -                              add(imm(-0.21460183f),
> +                              add(imm((float)(1.0 - M_PI_4)),

1 - M_PI_4 comes out to 0.21460 (positive), not -0.21460.  You
probably want to switch the operand order in the subtraction here
(unless this change was intentional).

--Aaron

>                                    mul(abs(x),
>                                        add(imm(0.086566724f),
>                                            mul(abs(x), imm(-0.03102955f))))))))));
> @@ -2586,7 +2586,7 @@ builtin_builder::_acos(const glsl_type *type)
>     ir_variable *x = in_var(type, "x");
>     MAKE_SIG(type, always_available, 1, x);
>
> -   body.emit(ret(sub(imm(1.5707964f), asin_expr(x))));
> +   body.emit(ret(sub(imm((float)M_PI_2), asin_expr(x))));
>
>     return sig;
>  }
> @@ -2623,13 +2623,13 @@ builtin_builder::_atan2(const glsl_type *type)
>        ir_if *inner_if = new(mem_ctx) ir_if(less(x, imm(0.0f)));
>        inner_if->then_instructions.push_tail(
>           if_tree(gequal(y, imm(0.0f)),
> -                 assign(r, add(r, imm(3.141593f))),
> -                 assign(r, sub(r, imm(3.141593f)))));
> +                 assign(r, add(r, imm((float)M_PI))),
> +                 assign(r, sub(r, imm((float)M_PI)))));
>        outer_then.emit(inner_if);
>
>        /* Else... */
>        outer_if->else_instructions.push_tail(
> -         assign(r, mul(sign(y), imm(1.5707965f))));
> +         assign(r, mul(sign(y), imm((float)M_PI_2))));
>
>        body.emit(outer_if);
>
> --
> 1.8.3.2
>
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