VideoCommon: Fix color channel logic when per-pixel lighting is in use

[Pokechu22]

Fixes bug 12698.

This was broken in #10012 (specifically by 06579e4 and c3dec34) when I attempted to simplify the logic incorrectly.

For color channel 0, this is approximately the code that is generated prior to that PR:

  if ((uid_data->components & VB_HAS_COL0) != 0)
  {
    out.Write("vertex_color_0 = rawcolor0;\n");
  }
  else
  {
    out.Write("vertex_color_0 = missing_color_value;\n");
  }

  // roughly
  out.write("o.colors_0 = LightingShaderCode(vertex_color_0);");

  if (uid_data->numColorChans == 0)
  {
    if ((uid_data->components & VB_HAS_COL0) != 0)
      out.Write("o.colors_0 = rawcolor0;\n");
    else
      out.Write("o.colors_0 = float4(1.0, 1.0, 1.0, 1.0);\n");
  }

  if (per_pixel_lighting)
  {
    if ((uid_data->components & VB_HAS_COL0) != 0)
      out.Write("o.colors_0 = vertex_color_0;\n");
  }
  else
  {
    if (uid_data->numColorChans == 0)
      out.Write("o.colors_0 = float4(0.0, 0.0, 0.0, 0.0);\n");
  }

Here is a table of results:

chans==0	VB_HAS_COL0	per-pixel	Result
Yes	Yes	Yes	vertex_color_0 => rawcolor0
Yes	Yes	No	float4(0, 0, 0, 0)
Yes	No	Yes	float4(1, 1, 1, 1) - vertex_color_0 => missing_color_value would also work
Yes	No	No	float4(0, 0, 0, 0)
No	Yes	Yes	vertex_color_0 => rawcolor0
No	Yes	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(rawcolor0)
No	No	Yes	LightingShaderCode(vertex_color_0) => LightingShaderCode(missing_color_value)
No	No	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(missing_color_value)

For color channel 0, this is approximately the code that is generated after that PR:

  if ((uid_data->components & VB_HAS_COL0) != 0)
  {
    out.Write("vertex_color_0 = rawcolor0;\n");
  }
  else
  {
    out.Write("vertex_color_0 = missing_color_value;\n");
  }

  // roughly
  out.write("o.colors_0 = LightingShaderCode(vertex_color_0);");

  if (uid_data->numColorChans == 0)
  {
    if ((uid_data->components & VB_HAS_COL0) != 0)
    {
      if (per_pixel_lighting)
        out.Write("o.colors_0 = vertex_color_0;\n");
      else
        out.Write("o.colors_0 = rawcolor0;\n");
    }
    else
    {
      out.Write("o.colors_0 = float4(0.0, 0.0, 0.0, 0.0);\n");
    }
  }

Here is a table of results:

chans==0	VB_HAS_COL0	per-pixel	Result
Yes	Yes	Yes	vertex_color_0 => rawcolor0
Yes	Yes	No	rawcolor0
Yes	No	Yes	float4(0, 0, 0, 0)
Yes	No	No	float4(0, 0, 0, 0)
No	Yes	Yes	LightingShaderCode(vertex_color_0) => LightingShaderCode(rawcolor0)
No	Yes	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(rawcolor0)
No	No	Yes	LightingShaderCode(vertex_color_0) => LightingShaderCode(missing_color_value)
No	No	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(missing_color_value)

As you can see, the results disagree in several places.

For color channel 0, this is approximately the code that is generated with this PR:

  if ((uid_data->components & VB_HAS_COL0) != 0)
  {
    out.Write("vertex_color_0 = rawcolor0;\n");
  }
  else
  {
    out.Write("vertex_color_0 = missing_color_value;\n");
  }

  // roughly
  out.write("o.colors_0 = LightingShaderCode(vertex_color_0);");

  if (per_pixel_lighting) {
    out.Write("o.colors_0 = vertex_color_0;\n");
  } else if (uid_data->numColorChans == 0)
    out.Write("o.colors_0 = float4(0.0, 0.0, 0.0, 0.0);\n");
  }

Here is a table of results:

chans==0	VB_HAS_COL0	per-pixel	Result
Yes	Yes	Yes	vertex_color_0 => rawcolor0
Yes	Yes	No	float4(0, 0, 0, 0)
Yes	No	Yes	vertex_color_0 => missing_color_value
Yes	No	No	float4(0, 0, 0, 0)
No	Yes	Yes	vertex_color_0 => rawcolor0
No	Yes	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(rawcolor0)
No	No	Yes	vertex_color_0 => missing_color_value
No	No	No	LightingShaderCode(vertex_color_0) => LightingShaderCode(missing_color_value)

These also don't match the old behavior, but now the pixel shader is always getting the raw color, never a pre-lit value.

In addition to fixing the darkness in Xenoblade Chronicles, this also makes the debug cubes in Super Mario Sunshine have the same brightness with per-pixel lighting enabled as with it disabled. (This only shows up with the fifoplayer; missing_color_value is set to 0 by gameini when launching the game normally.) Here are images from both games, along with the CRC32 hashes of those images to more easily identify distinct results:

Test	5.0-15105	5.0-15260	This PR
Super Mario Sunshine, no per-pixel lighting	2B87C475	2B87C475	2B87C475
Super Mario Sunshine, with per-pixel lighting	733708B3	6DF359AE	49E8A160
Xenoblade, no per-pixel lighting	378454C1	378454C1	378454C1
Xenoblade, with per-pixel lighting	6FC10472	64A4CC02	6FC10472

Both specialized shaders and ubershaders give exactly identical results for all of these.