mesa: add EXT_texture_compression_latc

The encoding/decoding algorithms are shared with RGTC.
Thanks to some magic with the base format, the RGTC texstore functions work
for LATC too.

swrast passes the related piglit tests besides two things:
- The alpha channel is wrong (it's always 1), however the incorrect alpha
  channel makes some other tests fail too, so I guess it's unrelated to LATC.
- Signed LATC fetches aren't correct yet (signed values are clamped to [0,1]),
  however RGTC has the same problem.

Further testing (with other of my patches) shows that hardware drivers
and softpipe work.

BTW, ETQW uses this extension.

13 files changed, 234 insertions, 7 deletions

diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 3840cdc5d3..519e94fec1 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -181,6 +181,7 @@ static const struct extension extension_table[] = {
    { "GL_EXT_texture3D",                           o(EXT_texture3D),                           GL             },
    { "GL_EXT_texture_array",                       o(EXT_texture_array),                       GL             },
    { "GL_EXT_texture_compression_dxt1",            o(EXT_texture_compression_s3tc),            GL | ES1 | ES2 },
+   { "GL_EXT_texture_compression_latc",            o(EXT_texture_compression_latc),            GL             },
    { "GL_EXT_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL             },
    { "GL_EXT_texture_compression_s3tc",            o(EXT_texture_compression_s3tc),            GL             },
    { "GL_EXT_texture_cube_map",                    o(ARB_texture_cube_map),                    GL             },
@@ -483,6 +484,7 @@ _mesa_enable_sw_extensions(struct gl_context *ctx)
    ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
    ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
    ctx->Extensions.EXT_texture_array = GL_TRUE;
+   ctx->Extensions.EXT_texture_compression_latc = GL_TRUE;
    ctx->Extensions.EXT_texture_env_add = GL_TRUE;
    ctx->Extensions.EXT_texture_env_combine = GL_TRUE;
    ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c
index 947db84a69..db10c9b4c2 100644
--- a/src/mesa/main/formats.c
+++ b/src/mesa/main/formats.c
@@ -927,6 +927,42 @@ static struct gl_format_info format_info[MESA_FORMAT_COUNT] =
      0, 0, 0, 0, 0,
      4, 4, 16                     /* 16 bytes per 4x4 block */
    },
+   {
+     MESA_FORMAT_L_LATC1,
+     "MESA_FORMAT_L_LATC1",
+     GL_LUMINANCE,
+     GL_UNSIGNED_NORMALIZED,
+     0, 0, 0, 0,
+     4, 0, 0, 0, 0,
+     4, 4, 8                     /* 8 bytes per 4x4 block */
+   },
+   {
+     MESA_FORMAT_SIGNED_L_LATC1,
+     "MESA_FORMAT_SIGNED_L_LATC1",
+     GL_LUMINANCE,
+     GL_SIGNED_NORMALIZED,
+     0, 0, 0, 0,
+     4, 0, 0, 0, 0,
+     4, 4, 8                     /* 8 bytes per 4x4 block */
+   },
+   {
+     MESA_FORMAT_LA_LATC2,
+     "MESA_FORMAT_LA_LATC2",
+     GL_LUMINANCE_ALPHA,
+     GL_UNSIGNED_NORMALIZED,
+     0, 0, 0, 4,
+     4, 0, 0, 0, 0,
+     4, 4, 16                     /* 16 bytes per 4x4 block */
+   },
+   {
+     MESA_FORMAT_SIGNED_LA_LATC2,
+     "MESA_FORMAT_SIGNED_LA_LATC2",
+     GL_LUMINANCE_ALPHA,
+     GL_SIGNED_NORMALIZED,
+     0, 0, 0, 4,
+     4, 0, 0, 0, 0,
+     4, 4, 16                     /* 16 bytes per 4x4 block */
+   },
 };
 
 
@@ -1570,6 +1606,10 @@ _mesa_format_to_type_and_comps(gl_format format,
    case MESA_FORMAT_SIGNED_RED_RGTC1:
    case MESA_FORMAT_RG_RGTC2:
    case MESA_FORMAT_SIGNED_RG_RGTC2:
+   case MESA_FORMAT_L_LATC1:
+   case MESA_FORMAT_SIGNED_L_LATC1:
+   case MESA_FORMAT_LA_LATC2:
+   case MESA_FORMAT_SIGNED_LA_LATC2:
       /* XXX generate error instead? */
       *datatype = GL_UNSIGNED_BYTE;
       *comps = 0;
diff --git a/src/mesa/main/formats.h b/src/mesa/main/formats.h
index e21967e2b0..04a18930b4 100644
--- a/src/mesa/main/formats.h
+++ b/src/mesa/main/formats.h
@@ -185,6 +185,14 @@ typedef enum
    MESA_FORMAT_RG_RGTC2,
    MESA_FORMAT_SIGNED_RG_RGTC2,
    /*@}*/
+
+   /*@{*/
+   MESA_FORMAT_L_LATC1,
+   MESA_FORMAT_SIGNED_L_LATC1,
+   MESA_FORMAT_LA_LATC2,
+   MESA_FORMAT_SIGNED_LA_LATC2,
+   /*@}*/
+
    MESA_FORMAT_COUNT
 } gl_format;
 
diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index 63936132f9..18abf2882a 100644
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -743,6 +743,10 @@ _mesa_is_color_format(GLenum format)
       case GL_COMPRESSED_SIGNED_RED_RGTC1:
       case GL_COMPRESSED_RG_RGTC2:
       case GL_COMPRESSED_SIGNED_RG_RGTC2:
+      case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+      case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+      case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+      case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
       /* signed, normalized texture formats */
       case GL_RGBA_SNORM:
       case GL_RGBA8_SNORM:
@@ -1025,6 +1029,11 @@ _mesa_is_compressed_format(struct gl_context *ctx, GLenum format)
    case GL_COMPRESSED_RG_RGTC2:
    case GL_COMPRESSED_SIGNED_RG_RGTC2:
       return ctx->Extensions.ARB_texture_compression_rgtc;
+   case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+   case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+   case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+   case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
+      return ctx->Extensions.EXT_texture_compression_latc;
    default:
       return GL_FALSE;
    }
diff --git a/src/mesa/main/mipmap.c b/src/mesa/main/mipmap.c
index 0727e1818f..e594160ad9 100644
--- a/src/mesa/main/mipmap.c
+++ b/src/mesa/main/mipmap.c
@@ -1764,8 +1764,13 @@ _mesa_generate_mipmap(struct gl_context *ctx, GLenum target,
       } else if (srcImage->_BaseFormat == GL_RGBA) {
          convertFormat = MESA_FORMAT_RGBA8888;
          components = 4;
-      }
-      else {
+      } else if (srcImage->_BaseFormat == GL_LUMINANCE) {
+         convertFormat = MESA_FORMAT_L8;
+         components = 1;
+      } else if (srcImage->_BaseFormat == GL_LUMINANCE_ALPHA) {
+         convertFormat = MESA_FORMAT_AL88;
+         components = 2;
+      } else {
          _mesa_problem(ctx, "bad srcImage->_BaseFormat in _mesa_generate_mipmaps");
          return;
       }
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 49ecea59d3..d10bb05b9a 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2802,6 +2802,7 @@ struct gl_extensions
    GLboolean EXT_texture_object;
    GLboolean EXT_texture3D;
    GLboolean EXT_texture_array;
+   GLboolean EXT_texture_compression_latc;
    GLboolean EXT_texture_compression_s3tc;
    GLboolean EXT_texture_env_add;
    GLboolean EXT_texture_env_combine;
diff --git a/src/mesa/main/texcompress.c b/src/mesa/main/texcompress.c
index 82d02ed0ec..942d996695 100644
--- a/src/mesa/main/texcompress.c
+++ b/src/mesa/main/texcompress.c
@@ -173,6 +173,15 @@ _mesa_glenum_to_compressed_format(GLenum format)
    case GL_COMPRESSED_SIGNED_RG_RGTC2:
       return MESA_FORMAT_SIGNED_RG_RGTC2;
 
+   case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+      return MESA_FORMAT_L_LATC1;
+   case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+      return MESA_FORMAT_SIGNED_L_LATC1;
+   case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+      return MESA_FORMAT_LA_LATC2;
+   case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
+      return MESA_FORMAT_SIGNED_LA_LATC2;
+
    default:
       return MESA_FORMAT_NONE;
    }
@@ -229,6 +238,15 @@ _mesa_compressed_format_to_glenum(struct gl_context *ctx, GLuint mesaFormat)
    case MESA_FORMAT_SIGNED_RG_RGTC2:
       return GL_COMPRESSED_SIGNED_RG_RGTC2;
 
+   case MESA_FORMAT_L_LATC1:
+      return GL_COMPRESSED_LUMINANCE_LATC1_EXT;
+   case MESA_FORMAT_SIGNED_L_LATC1:
+      return GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT;
+   case MESA_FORMAT_LA_LATC2:
+      return GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT;
+   case MESA_FORMAT_SIGNED_LA_LATC2:
+      return GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT;
+
    default:
       _mesa_problem(ctx, "Unexpected mesa texture format in"
                     " _mesa_compressed_format_to_glenum()");
diff --git a/src/mesa/main/texcompress_rgtc.c b/src/mesa/main/texcompress_rgtc.c
index 26dca2d760..c50df19c5d 100644
--- a/src/mesa/main/texcompress_rgtc.c
+++ b/src/mesa/main/texcompress_rgtc.c
@@ -98,7 +98,8 @@ _mesa_texstore_red_rgtc1(TEXSTORE_PARAMS)
    GLubyte srcpixels[4][4];
    GLubyte *blkaddr;
    GLint dstRowDiff;
-   ASSERT(dstFormat == MESA_FORMAT_RED_RGTC1);
+   ASSERT(dstFormat == MESA_FORMAT_RED_RGTC1 ||
+          dstFormat == MESA_FORMAT_L_LATC1);
    ASSERT(dstXoffset % 4 == 0);
    ASSERT(dstYoffset % 4 == 0);
    ASSERT(dstZoffset % 4 == 0);
@@ -153,7 +154,8 @@ _mesa_texstore_signed_red_rgtc1(TEXSTORE_PARAMS)
    GLbyte srcpixels[4][4];
    GLbyte *blkaddr;
    GLint dstRowDiff;
-   ASSERT(dstFormat == MESA_FORMAT_SIGNED_RED_RGTC1);
+   ASSERT(dstFormat == MESA_FORMAT_SIGNED_RED_RGTC1 ||
+          dstFormat == MESA_FORMAT_SIGNED_L_LATC1);
    ASSERT(dstXoffset % 4 == 0);
    ASSERT(dstYoffset % 4 == 0);
    ASSERT(dstZoffset % 4 == 0);
@@ -208,7 +210,8 @@ _mesa_texstore_rg_rgtc2(TEXSTORE_PARAMS)
    GLubyte *blkaddr;
    GLint dstRowDiff;
 
-   ASSERT(dstFormat == MESA_FORMAT_RG_RGTC2);
+   ASSERT(dstFormat == MESA_FORMAT_RG_RGTC2 ||
+          dstFormat == MESA_FORMAT_LA_LATC2);
    ASSERT(dstXoffset % 4 == 0);
    ASSERT(dstYoffset % 4 == 0);
    ASSERT(dstZoffset % 4 == 0);
@@ -269,7 +272,8 @@ _mesa_texstore_signed_rg_rgtc2(TEXSTORE_PARAMS)
    GLbyte *blkaddr;
    GLint dstRowDiff;
 
-   ASSERT(dstFormat == MESA_FORMAT_SIGNED_RG_RGTC2);
+   ASSERT(dstFormat == MESA_FORMAT_SIGNED_RG_RGTC2 ||
+          dstFormat == MESA_FORMAT_SIGNED_LA_LATC2);
    ASSERT(dstXoffset % 4 == 0);
    ASSERT(dstYoffset % 4 == 0);
    ASSERT(dstZoffset % 4 == 0);
@@ -374,6 +378,62 @@ _mesa_fetch_texel_2d_f_signed_rg_rgtc2(const struct gl_texture_image *texImage,
    texel[ACOMP] = 1.0;
 }
 
+void
+_mesa_fetch_texel_2d_f_l_latc1(const struct gl_texture_image *texImage,
+                                 GLint i, GLint j, GLint k, GLfloat *texel)
+{
+   GLubyte red;
+   unsigned_fetch_texel_rgtc(texImage->RowStride, (GLubyte *)(texImage->Data),
+                       i, j, &red, 1);
+   texel[RCOMP] =
+   texel[GCOMP] =
+   texel[BCOMP] = UBYTE_TO_FLOAT(red);
+   texel[ACOMP] = 1.0;
+}
+
+void
+_mesa_fetch_texel_2d_f_signed_l_latc1(const struct gl_texture_image *texImage,
+                                        GLint i, GLint j, GLint k, GLfloat *texel)
+{
+   GLbyte red;
+   signed_fetch_texel_rgtc(texImage->RowStride, (GLbyte *)(texImage->Data),
+                       i, j, &red, 1);
+   texel[RCOMP] =
+   texel[GCOMP] =
+   texel[BCOMP] = BYTE_TO_FLOAT_TEX(red);
+   texel[ACOMP] = 1.0;
+}
+
+void
+_mesa_fetch_texel_2d_f_la_latc2(const struct gl_texture_image *texImage,
+                                 GLint i, GLint j, GLint k, GLfloat *texel)
+{
+   GLubyte red, green;
+   unsigned_fetch_texel_rgtc(texImage->RowStride, (GLubyte *)(texImage->Data),
+                     i, j, &red, 2);
+   unsigned_fetch_texel_rgtc(texImage->RowStride, (GLubyte *)(texImage->Data) + 8,
+                     i, j, &green, 2);
+   texel[RCOMP] =
+   texel[GCOMP] =
+   texel[BCOMP] = UBYTE_TO_FLOAT(red);
+   texel[ACOMP] = UBYTE_TO_FLOAT(green);
+}
+
+void
+_mesa_fetch_texel_2d_f_signed_la_latc2(const struct gl_texture_image *texImage,
+                                       GLint i, GLint j, GLint k, GLfloat *texel)
+{
+   GLbyte red, green;
+   signed_fetch_texel_rgtc(texImage->RowStride, (GLbyte *)(texImage->Data),
+                     i, j, &red, 2);
+   signed_fetch_texel_rgtc(texImage->RowStride, (GLbyte *)(texImage->Data) + 8,
+                     i, j, &green, 2);
+   texel[RCOMP] =
+   texel[GCOMP] =
+   texel[BCOMP] = BYTE_TO_FLOAT_TEX(red);
+   texel[ACOMP] = BYTE_TO_FLOAT_TEX(green);
+}
+
 #define TAG(x) unsigned_##x
 
 #define TYPE GLubyte
diff --git a/src/mesa/main/texcompress_rgtc.h b/src/mesa/main/texcompress_rgtc.h
index 424edc4581..18766770d7 100644
--- a/src/mesa/main/texcompress_rgtc.h
+++ b/src/mesa/main/texcompress_rgtc.h
@@ -57,4 +57,21 @@ _mesa_fetch_texel_2d_f_rg_rgtc2(const struct gl_texture_image *texImage,
 extern void
 _mesa_fetch_texel_2d_f_signed_rg_rgtc2(const struct gl_texture_image *texImage,
 				       GLint i, GLint j, GLint k, GLfloat *texel);
+
+extern void
+_mesa_fetch_texel_2d_f_l_latc1(const struct gl_texture_image *texImage,
+                                 GLint i, GLint j, GLint k, GLfloat *texel);
+
+extern void
+_mesa_fetch_texel_2d_f_signed_l_latc1(const struct gl_texture_image *texImage,
+                                        GLint i, GLint j, GLint k, GLfloat *texel);
+
+extern void
+_mesa_fetch_texel_2d_f_la_latc2(const struct gl_texture_image *texImage,
+                                 GLint i, GLint j, GLint k, GLfloat *texel);
+
+extern void
+_mesa_fetch_texel_2d_f_signed_la_latc2(const struct gl_texture_image *texImage,
+                                       GLint i, GLint j, GLint k, GLfloat *texel);
+
 #endif
diff --git a/src/mesa/main/texfetch.c b/src/mesa/main/texfetch.c
index 550597e1cd..988a7e0546 100644
--- a/src/mesa/main/texfetch.c
+++ b/src/mesa/main/texfetch.c
@@ -786,6 +786,34 @@ texfetch_funcs[MESA_FORMAT_COUNT] =
       NULL,
       NULL
    },
+   {
+      MESA_FORMAT_L_LATC1,
+      NULL,
+      _mesa_fetch_texel_2d_f_l_latc1,
+      NULL,
+      NULL
+   },
+   {
+      MESA_FORMAT_SIGNED_L_LATC1,
+      NULL,
+      _mesa_fetch_texel_2d_f_signed_l_latc1,
+      NULL,
+      NULL
+   },
+   {
+      MESA_FORMAT_LA_LATC2,
+      NULL,
+      _mesa_fetch_texel_2d_f_la_latc2,
+      NULL,
+      NULL
+   },
+   {
+      MESA_FORMAT_SIGNED_LA_LATC2,
+      NULL,
+      _mesa_fetch_texel_2d_f_signed_la_latc2,
+      NULL,
+      NULL
+   },
 };
 
 
diff --git a/src/mesa/main/texformat.c b/src/mesa/main/texformat.c
index 72025cf828..521b9a04b7 100644
--- a/src/mesa/main/texformat.c
+++ b/src/mesa/main/texformat.c
@@ -621,6 +621,25 @@ _mesa_choose_tex_format( struct gl_context *ctx, GLint internalFormat,
       }
    }
 
+   if (ctx->Extensions.EXT_texture_compression_latc) {
+      switch (internalFormat) {
+         case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+            RETURN_IF_SUPPORTED(MESA_FORMAT_L_LATC1);
+            break;
+         case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+            RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_L_LATC1);
+            break;
+         case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+            RETURN_IF_SUPPORTED(MESA_FORMAT_LA_LATC2);
+            break;
+         case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
+            RETURN_IF_SUPPORTED(MESA_FORMAT_SIGNED_LA_LATC2);
+            break;
+         default:
+            ; /* fallthrough */
+      }
+   }
+
    _mesa_problem(ctx, "unexpected format in _mesa_choose_tex_format()");
    return MESA_FORMAT_NONE;
 }
diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index d4ae6dd69d..6ec66100e7 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -509,6 +509,19 @@ _mesa_base_tex_format( struct gl_context *ctx, GLint internalFormat )
       }
    }
 
+   if (ctx->Extensions.EXT_texture_compression_latc) {
+      switch (internalFormat) {
+      case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
+      case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
+         return GL_LUMINANCE;
+      case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
+      case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
+         return GL_LUMINANCE_ALPHA;
+      default:
+         ; /* fallthrough */
+      }
+   }
+
    return -1; /* error */
 }
 
diff --git a/src/mesa/main/texstore.c b/src/mesa/main/texstore.c
index cd30fa0214..760cdfa854 100644
--- a/src/mesa/main/texstore.c
+++ b/src/mesa/main/texstore.c
@@ -4135,7 +4135,14 @@ texstore_funcs[MESA_FORMAT_COUNT] =
    { MESA_FORMAT_RED_RGTC1, _mesa_texstore_red_rgtc1 },
    { MESA_FORMAT_SIGNED_RED_RGTC1, _mesa_texstore_signed_red_rgtc1 },
    { MESA_FORMAT_RG_RGTC2, _mesa_texstore_rg_rgtc2 },
-   { MESA_FORMAT_SIGNED_RG_RGTC2, _mesa_texstore_signed_rg_rgtc2 }
+   { MESA_FORMAT_SIGNED_RG_RGTC2, _mesa_texstore_signed_rg_rgtc2 },
+
+   /* Re-use the R/RG texstore functions.
+    * The code is generic enough to handle LATC too. */
+   { MESA_FORMAT_L_LATC1, _mesa_texstore_red_rgtc1 },
+   { MESA_FORMAT_SIGNED_L_LATC1, _mesa_texstore_signed_red_rgtc1 },
+   { MESA_FORMAT_LA_LATC2, _mesa_texstore_rg_rgtc2 },
+   { MESA_FORMAT_SIGNED_LA_LATC2, _mesa_texstore_signed_rg_rgtc2 }
 };