[PATCH v2 1/8] wined3d: Alpha test emulation for core profile contexts.

[Henri Verbeet]

On 19 April 2016 at 18:56, Matteo Bruni <mbruni at codeweavers.com> wrote:
> +    /* alpha_func is the PASS condition, not the DISCARD condition. Instead of
> +     * flipping all the operators here, just negate the comparison below. */
As an aside, note that in general inverting operators isn't safe if
there are potential NaNs involved.

> +    static const char *comparison_operator[] =
> +    {
> +        "",   /* WINED3D_CMP_NEVER */
> +        "<",  /* WINED3D_CMP_LESS */
> +        "==", /* WINED3D_CMP_EQUAL */
> +        "<=", /* WINED3D_CMP_LESSEQUAL */
> +        ">",  /* WINED3D_CMP_GREATER */
> +        "!=", /* WINED3D_CMP_NOTEQUAL */
> +        ">=", /* WINED3D_CMP_GREATEREQUAL */
> +        ""    /* WINED3D_CMP_ALWAYS */
> +    };
I should have noticed the first time, but I think you'll want to make
the string pointers const as well.

> @@ -3091,6 +3091,13 @@ void find_ps_compile_args(const struct wined3d_state *state, const struct wined3
>      args->pointsprite = state->render_states[WINED3D_RS_POINTSPRITEENABLE]
>              && state->gl_primitive_type == GL_POINTS;
>
> +    if (gl_info->supported[WINED3D_GL_LEGACY_CONTEXT])
> +        args->alpha_test_func = WINED3D_CMP_ALWAYS - 1;
> +    else
> +        args->alpha_test_func = (state->render_states[WINED3D_RS_ALPHATESTENABLE]
> +                ? wined3d_sanitize_cmp_func(state->render_states[WINED3D_RS_ALPHAFUNC])
> +                : WINED3D_CMP_ALWAYS) - 1;
For what it's worth, what I originally had in mind was mapping
WINED3D_CMP_ALWAYS to 0. I.e., masking with 7. This works as well.