formats: Add support for EXT_texture_sRGB_R8 if host supports it.

This is a GLES only extension and the format is also only supported
on a GLES host.

Enables and passes on a host that supports it:
  dEQP-GLES31.functional.texture.filtering.cube_array.formats.sr8*
  dEQP-GLES31.functional.srgb_texture_decode.skip_decode.sr8.*

Closes: #49

Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Signed-off-by: Jakob Bornecrantz <jakob@collabora.com>

src/gallium/auxiliary/util/u_format.csv

@@ -112,6 +112,7 @@ PIPE_FORMAT_I32_FLOAT             , plain, 1, 1, f32 ,     ,     ,     , xxxx, r
 
 # SRGB formats
 PIPE_FORMAT_L8_SRGB               , plain, 1, 1, un8 ,     ,     ,     , xxx1, srgb 
+PIPE_FORMAT_R8_SRGB               , plain, 1, 1, un8 ,     ,     ,     , x001, srgb
 PIPE_FORMAT_L8A8_SRGB             , plain, 1, 1, un8 , un8 ,     ,     , xxxy, srgb 
 PIPE_FORMAT_R8G8B8_SRGB           , plain, 1, 1, un8 , un8 , un8 ,     , xyz1, srgb 
 PIPE_FORMAT_R8G8B8A8_SRGB         , plain, 1, 1, un8 , un8 , un8 , un8 , xyzw, srgb 

src/gallium/include/pipe/p_format.h

@@ -396,6 +396,8 @@ enum pipe_format {
    PIPE_FORMAT_X1B5G5R5_UNORM          = 310,
    PIPE_FORMAT_A4B4G4R4_UNORM          = 311,
 
+   PIPE_FORMAT_R8_SRGB                 = 312,
+
    PIPE_FORMAT_COUNT
 };
 

src/virgl_hw.h

@@ -214,6 +214,8 @@ enum virgl_formats {
 
    VIRGL_FORMAT_R10G10B10X2_UNORM       = 308,
    VIRGL_FORMAT_A4B4G4R4_UNORM          = 311,
+
+   VIRGL_FORMAT_R8_SRGB                 = 312,
    VIRGL_FORMAT_MAX,
 };
 

src/vrend_formats.c

@@ -258,6 +258,11 @@ static struct vrend_format_table gl_srgb_formats[] =
   { VIRGL_FORMAT_B8G8R8A8_SRGB, GL_SRGB8_ALPHA8, GL_BGRA, GL_UNSIGNED_BYTE, NO_SWIZZLE },
 };
 
+static struct vrend_format_table gles_srgb_r8_format[] =
+{
+   { VIRGL_FORMAT_R8_SRGB, GL_SR8_EXT, GL_RED, GL_UNSIGNED_BYTE, NO_SWIZZLE },
+};
+
 static struct vrend_format_table bit10_formats[] = {
   { VIRGL_FORMAT_B10G10R10X2_UNORM, GL_RGB10_A2, GL_BGRA, GL_UNSIGNED_INT_2_10_10_10_REV, RGB1_SWIZZLE },
   { VIRGL_FORMAT_B10G10R10A2_UNORM, GL_RGB10_A2, GL_BGRA, GL_UNSIGNED_INT_2_10_10_10_REV, NO_SWIZZLE },
@@ -467,6 +472,7 @@ void vrend_build_format_list_gles(void)
    */
   add_formats(gles_bgra_formats);
 
+  add_formats(gles_srgb_r8_format);
 
   /* The Z32 format is required, but OpenGL ES does not support
    * using it as a depth buffer. We just fake support with Z24