[PATCH 2/5] wined3d: Implement SM4 discard in the GLSL shader backend.

[Matteo Bruni]

2015-06-15 14:07 GMT+02:00 Henri Verbeet <hverbeet at codeweavers.com>:
> ---
>  dlls/wined3d/glsl_shader.c | 35 +++++++++++++++++++++--------------
>  1 file changed, 21 insertions(+), 14 deletions(-)
>
> diff --git a/dlls/wined3d/glsl_shader.c b/dlls/wined3d/glsl_shader.c
> index 5ba246e..eb98ffe 100644
> --- a/dlls/wined3d/glsl_shader.c
> +++ b/dlls/wined3d/glsl_shader.c
> @@ -4704,22 +4704,29 @@ static void shader_glsl_texreg2rgb(const struct wined3d_shader_instruction *ins)
>   * If any of the first 3 components are < 0, discard this pixel */
>  static void shader_glsl_texkill(const struct wined3d_shader_instruction *ins)
>  {
> -    struct glsl_dst_param dst_param;
> +    if (ins->ctx->reg_maps->shader_version.major >= 4)
> +    {
> +        struct glsl_src_param src_param;
>
> -    /* The argument is a destination parameter, and no writemasks are allowed */
> -    shader_glsl_add_dst_param(ins, &ins->dst[0], &dst_param);
> -    if (ins->ctx->reg_maps->shader_version.major >= 2)
> +        shader_glsl_add_src_param(ins, &ins->src[0], WINED3DSP_WRITEMASK_0, &src_param);
> +        shader_addline(ins->ctx->buffer, "if (bool(floatBitsToUint(%s))) discard;\n", src_param.param_str);
> +    }
> +    else
>      {
> -        if (ins->ctx->reg_maps->shader_version.major >= 4)
> -            FIXME("SM4 discard not implemented.\n");
> -        /* 2.0 shaders compare all 4 components in texkill */
> -        shader_addline(ins->ctx->buffer, "if (any(lessThan(%s.xyzw, vec4(0.0)))) discard;\n", dst_param.reg_name);
> -    } else {
> -        /* 1.X shaders only compare the first 3 components, probably due to the nature of the texkill
> -         * instruction as a tex* instruction, and phase, which kills all a / w components. Even if all
> -         * 4 components are defined, only the first 3 are used
> -         */
> -        shader_addline(ins->ctx->buffer, "if (any(lessThan(%s.xyz, vec3(0.0)))) discard;\n", dst_param.reg_name);
> +        struct glsl_dst_param dst_param;
> +
> +        /* The argument is a destination parameter, and no writemasks are allowed */
> +        shader_glsl_add_dst_param(ins, &ins->dst[0], &dst_param);
> +
> +        /* 2.0 shaders compare all 4 components in texkill. */
> +        if (ins->ctx->reg_maps->shader_version.major >= 2)
> +            shader_addline(ins->ctx->buffer, "if (any(lessThan(%s.xyzw, vec4(0.0)))) discard;\n", dst_param.reg_name);
> +        /* 1.x shaders only compare the first 3 components, probably due to
> +         * the nature of the texkill instruction as a tex* instruction, and
> +         * phase, which kills all .w components. Even if all 4 components are
> +         * defined, only the first 3 are used. */
> +        else
> +            shader_addline(ins->ctx->buffer, "if (any(lessThan(%s.xyz, vec3(0.0)))) discard;\n", dst_param.reg_name);
>      }
>  }
>
> --
> 2.1.4

FWIW, https://msdn.microsoft.com/en-us/library/windows/desktop/hh446968%28v=vs.85%29.aspx
mentions two variants of the discard instruction. Any clue how is that
_z vs _nz part encoded?