[PATCH 3/8] wined3d: Simplify shader interface matching for SM4+ vertex shaders.

[Matteo Bruni]

2016-04-20 12:50 GMT+02:00 Henri Verbeet <hverbeet at gmail.com>:
> On 19 April 2016 at 18:56, Matteo Bruni <mbruni at codeweavers.com> wrote:
>> After some testing it looks like, with SM4+ on Windows:
>> 1. Output registers have to match with input registers from the
>> following shader stage (register index and mask). There is no "smart"
>> matching of semantics like in SM3.
>> 2. Using uninitialized varyings in SM4+ shaders doesn't give consistent
>> results.
>> That means we can simplify the relevant code quite a bit. Applications
>> shouldn't be able to depend on particular values for uninitialized
>> varyings so we can avoid explicitly initializing them.
>>
> Does that mean we don't need the separate "reorder" shader between the
> stages? (Even more so if we have separate shader objects.)

We shouldn't really need separate "reorder" shaders for SM4+, correct.
At the moment I'm still making use of the separate shader for the
setup_vs_output() function to be able to use the same VS variant both
with and without a GS. Of course that means right now we need to
compile the "setup" shader in that case which is arguably worse than a
shader variant.
I had in mind to look into that at some point after this first "pass"
at fixing shaders matching but maybe that's not a good plan. I guess
I'll have a shot at dropping the separate shader for SM4 and see what
happens...

> On 19 April 2016 at 18:56, Matteo Bruni <mbruni at codeweavers.com> wrote:
>> -static void shader_glsl_setup_shader_output(struct shader_glsl_priv *priv,
>> +static void shader_glsl_setup_vs3_output(struct shader_glsl_priv *priv,
>>          const struct wined3d_gl_info *gl_info, const DWORD *map,
>>          const struct wined3d_shader_signature *input_signature,
>>          const struct wined3d_shader_reg_maps *reg_maps_in,
>>          const struct wined3d_shader_signature *output_signature,
>> -        const struct wined3d_shader_reg_maps *reg_maps_out, const char *out_array_name)
>> +        const struct wined3d_shader_reg_maps *reg_maps_out)
>>  {
>>      struct wined3d_string_buffer *destination = string_buffer_get(&priv->string_buffers);
>>      BOOL legacy_context = gl_info->supported[WINED3D_GL_LEGACY_CONTEXT];
>> @@ -5191,7 +5191,7 @@ static void shader_glsl_setup_shader_output(struct shader_glsl_priv *priv,
>>          else if (in_idx == in_count + 1)
>>              string_buffer_sprintf(destination, "gl_FrontSecondaryColor");
>>          else
>> -            string_buffer_sprintf(destination, "%s[%u]", out_array_name, in_idx);
>> +            string_buffer_sprintf(destination, "%s[%u]", "ps_link", in_idx);
>>
>>          if (!set[in_idx])
>>              set[in_idx] = ~0u;
>> @@ -5243,7 +5243,7 @@ static void shader_glsl_setup_shader_output(struct shader_glsl_priv *priv,
>>          else if (i == in_count + 1)
>>              string_buffer_sprintf(destination, "gl_FrontSecondaryColor");
>>          else
>> -            string_buffer_sprintf(destination, "%s[%u]", out_array_name, i);
>> +            string_buffer_sprintf(destination, "%s[%u]", "ps_link", i);
>>
>>          if (size == 1)
>>              shader_addline(buffer, "%s.%s = 0.0;\n", destination->buffer, reg_mask);
> This looks like you should have just kept it the way it was in the
> previous patch.

Sure, I can drop that change. Actually it was like that until a couple
of days ago (I reread these patches way too many times...)