[Mesa-dev] [PATCH 08/22] mesa: Add decoding functions for GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC

Anuj Phogat anuj.phogat at gmail.com
Fri Nov 9 23:29:55 PST 2012


v2: Use MESA_FORMAT_SARGB8 to store the decoded texture data
Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
---
 src/mesa/main/texcompress_etc.c |   96 +++++++++++++++++++++++++++++++++++---
 src/mesa/main/texcompress_etc.h |    9 +++-
 2 files changed, 96 insertions(+), 9 deletions(-)

diff --git a/src/mesa/main/texcompress_etc.c b/src/mesa/main/texcompress_etc.c
index c04ba8d..9940375 100644
--- a/src/mesa/main/texcompress_etc.c
+++ b/src/mesa/main/texcompress_etc.c
@@ -28,6 +28,7 @@
  * GL_COMPRESSED_RGB8_ETC2
  * GL_COMPRESSED_SRGB8_ETC2
  * GL_COMPRESSED_RGBA8_ETC2_EAC
+ * GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
  */
 
 #include <stdbool.h>
@@ -494,6 +495,14 @@ etc2_alpha8_fetch_texel(const struct etc2_block *block,
 }
 
 static void
+etc2_rgba8_fetch_texel(const struct etc2_block *block,
+      int x, int y, GLubyte *dst)
+{
+   etc2_rgb8_fetch_texel(block, x, y, dst);
+   etc2_alpha8_fetch_texel(block, x, y, dst);
+}
+
+static void
 etc2_alpha8_parse_block(struct etc2_block *block, const GLubyte *src)
 {
    block->base_codeword = src[0];
@@ -517,14 +526,6 @@ etc2_rgba8_parse_block(struct etc2_block *block, const GLubyte *src)
    etc2_alpha8_parse_block(block, src);
 }
 
-static void
-etc2_rgba8_fetch_texel(const struct etc2_block *block,
-      int x, int y, GLubyte *dst)
-{
-   etc2_rgb8_fetch_texel(block, x, y, dst);
-   etc2_alpha8_fetch_texel(block, x, y, dst);
-}
-
 /**
  * Convert an 8-bit sRGB value from non-linear space to a
  * linear RGB value in [0, 1].
@@ -662,6 +663,50 @@ etc2_unpack_rgba8(uint8_t *dst_row,
     }
 }
 
+static void
+etc2_unpack_srgb8_alpha8(uint8_t *dst_row,
+                         unsigned dst_stride,
+                         const uint8_t *src_row,
+                         unsigned src_stride,
+                         unsigned width,
+                         unsigned height)
+{
+   /* If internalformat is COMPRESSED_SRGB8_ALPHA8_ETC2_EAC, each 4 × 4 block
+    * of RGBA8888 information is compressed to 128 bits. To decode a block, the
+      two 64-bit integers int64bitAlpha and int64bitColor are calculated.
+   */
+   const unsigned bw = 4, bh = 4, bs = 16, comps = 4;
+   struct etc2_block block;
+   unsigned x, y, i, j;
+   uint8_t tmp;
+
+   for (y = 0; y < height; y += bh) {
+      const uint8_t *src = src_row;
+
+      for (x = 0; x < width; x+= bw) {
+         etc2_rgba8_parse_block(&block, src);
+
+         for (j = 0; j < bh; j++) {
+            uint8_t *dst = dst_row + (y + j) * dst_stride + x * comps;
+            for (i = 0; i < bw; i++) {
+               etc2_rgba8_fetch_texel(&block, i, j, dst);
+
+               /* Convert to MESA_FORMAT_SARGB8 */
+	       tmp = dst[0];
+               dst[0] = dst[2];
+               dst[2] = tmp;
+               dst[3] = dst[3];
+
+               dst += comps;
+            }
+         }
+         src += bs;
+       }
+
+      src_row += src_stride;
+    }
+}
+
 /* ETC2 texture formats are valid in glCompressedTexImage2D and
  * glCompressedTexSubImage2D functions */
 GLboolean
@@ -688,6 +733,14 @@ _mesa_texstore_etc2_rgba8_eac(TEXSTORE_PARAMS)
    return GL_FALSE;
 }
 
+GLboolean
+_mesa_texstore_etc2_srgb8_alpha8_eac(TEXSTORE_PARAMS)
+{
+   ASSERT(0);
+
+   return GL_FALSE;
+}
+
 void
 _mesa_fetch_texel_2d_f_etc2_rgb8(const struct swrast_texture_image *texImage,
                                  GLint i, GLint j, GLint k, GLfloat *texel)
@@ -748,11 +801,34 @@ _mesa_fetch_texel_2d_f_etc2_rgba8_eac(const struct swrast_texture_image *texImag
    texel[ACOMP] = UBYTE_TO_FLOAT(dst[3]);
 }
 
+void
+_mesa_fetch_texel_2d_f_etc2_srgb8_alpha8_eac(const struct
+                                             swrast_texture_image *texImage,
+                                             GLint i, GLint j,
+					     GLint k, GLfloat *texel)
+{
+   struct etc2_block block;
+   GLubyte dst[4];
+   const GLubyte *src;
+
+   src = (const GLubyte *) texImage->Map +
+      (((texImage->RowStride + 3) / 4) * (j / 4) + (i / 4)) * 16;
+
+   etc2_rgba8_parse_block(&block, src);
+   etc2_rgba8_fetch_texel(&block, i % 4, j % 4, dst);
+
+   texel[RCOMP] = nonlinear_to_linear(dst[0]);
+   texel[GCOMP] = nonlinear_to_linear(dst[1]);
+   texel[BCOMP] = nonlinear_to_linear(dst[2]);
+   texel[ACOMP] = UBYTE_TO_FLOAT(dst[3]);
+}
+
 /**
  * Decode texture data in any one of following formats:
  * `MESA_FORMAT_ETC2_RGB8`
  * `MESA_FORMAT_ETC2_SRGB8`
  * `MESA_FORMAT_ETC2_RGBA8_EAC`
+ * `MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC`
  *
  * The size of the source data must be a multiple of the ETC2 block size
  * even if the texture image's dimensions are not aligned to 4.
@@ -783,4 +859,8 @@ _mesa_unpack_etc2_format(uint8_t *dst_row,
       etc2_unpack_rgba8(dst_row, dst_stride,
                         src_row, src_stride,
                         src_width, src_height);
+   else if (format == MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC)
+      etc2_unpack_srgb8_alpha8(dst_row, dst_stride,
+                               src_row, src_stride,
+                               src_width, src_height);
 }
diff --git a/src/mesa/main/texcompress_etc.h b/src/mesa/main/texcompress_etc.h
index 2191c97..c10414d 100644
--- a/src/mesa/main/texcompress_etc.h
+++ b/src/mesa/main/texcompress_etc.h
@@ -43,6 +43,9 @@ _mesa_texstore_etc2_srgb8(TEXSTORE_PARAMS);
 GLboolean
 _mesa_texstore_etc2_rgba8_eac(TEXSTORE_PARAMS);
 
+GLboolean
+_mesa_texstore_etc2_srgb8_alpha8_eac(TEXSTORE_PARAMS);
+
 void
 _mesa_fetch_texel_2d_f_etc1_rgb8(const struct swrast_texture_image *texImage,
                                  GLint i, GLint j, GLint k, GLfloat *texel);
@@ -55,7 +58,11 @@ _mesa_fetch_texel_2d_f_etc2_srgb8(const struct swrast_texture_image *texImage,
 void
 _mesa_fetch_texel_2d_f_etc2_rgba8_eac(const struct swrast_texture_image *texImage,
                                       GLint i, GLint j, GLint k, GLfloat *texel);
-
+void
+_mesa_fetch_texel_2d_f_etc2_srgb8_alpha8_eac(const struct
+                                            swrast_texture_image *texImage,
+                                            GLint i, GLint j,
+					    GLint k, GLfloat *texel);
 void
 _mesa_etc1_unpack_rgba8888(uint8_t *dst_row,
                            unsigned dst_stride,
-- 
1.7.7.6



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