mesa: add new signed rgba texture format

This is a (partial) backport of the signed texture format support in OGL 3.1.
Since it wasn't promoted from an existing extension roll our own.

18 files changed, 342 insertions, 45 deletions

diff --git a/src/mesa/glapi/gl_API.xml b/src/mesa/glapi/gl_API.xml
index cc3e3ae6bf..ef774f2e60 100644
--- a/src/mesa/glapi/gl_API.xml
+++ b/src/mesa/glapi/gl_API.xml
@@ -12326,6 +12326,12 @@
     </function>
 </category>
 
+<category name="GL_MESA_texture_signed_rgba">
+    <enum name="SIGNED_NORMALIZED"                        value="0x8F9C"/>
+    <enum name="RGBA_SNORM"                               value="0x8F93"/>
+    <enum name="RGBA8_SNORM"                              value="0x8F97"/>
+</category>
+
 <category name="GL_MESA_shader_debug">
     <enum name="DEBUG_OBJECT_MESA"                        value="0x8759"/>
     <enum name="DEBUG_PRINT_MESA"                         value="0x875A"/>
diff --git a/src/mesa/main/colortab.c b/src/mesa/main/colortab.c
index bd9cf438b4..b05c0513aa 100644
--- a/src/mesa/main/colortab.c
+++ b/src/mesa/main/colortab.c
@@ -718,7 +718,7 @@ _mesa_GetColorTable( GLenum target, GLenum format,
    }
 
    _mesa_pack_rgba_span_float(ctx, table->Size, rgba,
-                              format, type, data, &ctx->Pack, 0x0);
+                              format, type, data, &ctx->Pack, 0x0, GL_FALSE);
 
    if (ctx->Pack.BufferObj->Name) {
       ctx->Driver.UnmapBuffer(ctx, GL_PIXEL_PACK_BUFFER_EXT,
diff --git a/src/mesa/main/convolve.c b/src/mesa/main/convolve.c
index 814c6a0a5a..63b652bf70 100644
--- a/src/mesa/main/convolve.c
+++ b/src/mesa/main/convolve.c
@@ -626,7 +626,7 @@ _mesa_GetConvolutionFilter(GLenum target, GLenum format, GLenum type,
                                           row, 0);
       GLfloat (*src)[4] = (GLfloat (*)[4]) (filter->Filter + row * filter->Width * 4);
       _mesa_pack_rgba_span_float(ctx, filter->Width, src,
-                                 format, type, dst, &ctx->Pack, 0x0);
+                                 format, type, dst, &ctx->Pack, 0x0, GL_FALSE);
    }
 
    if (ctx->Pack.BufferObj->Name) {
@@ -836,7 +836,7 @@ _mesa_GetSeparableFilter(GLenum target, GLenum format, GLenum type,
                                           format, type, 0);
       _mesa_pack_rgba_span_float(ctx, filter->Width,
                                  (GLfloat (*)[4]) filter->Filter,
-                                 format, type, dst, &ctx->Pack, 0x0);
+                                 format, type, dst, &ctx->Pack, 0x0, GL_FALSE);
    }
 
    /* Column filter */
@@ -845,7 +845,7 @@ _mesa_GetSeparableFilter(GLenum target, GLenum format, GLenum type,
                                           format, type, 0);
       GLfloat (*src)[4] = (GLfloat (*)[4]) (filter->Filter + colStart);
       _mesa_pack_rgba_span_float(ctx, filter->Height, src,
-                                 format, type, dst, &ctx->Pack, 0x0);
+                                 format, type, dst, &ctx->Pack, 0x0, GL_FALSE);
    }
 
    (void) span;  /* unused at this time */
diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 2d2bf51784..147d923e64 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -150,6 +150,7 @@ static const struct {
    { OFF, "GL_MESA_packed_depth_stencil",      F(MESA_packed_depth_stencil) },
    { OFF, "GL_MESA_resize_buffers",            F(MESA_resize_buffers) },
    { OFF, "GL_MESA_texture_array",             F(MESA_texture_array) },
+   { OFF, "GL_MESA_texture_signed_rgba",       F(MESA_texture_signed_rgba) },
    { OFF, "GL_MESA_ycbcr_texture",             F(MESA_ycbcr_texture) },
    { ON,  "GL_MESA_window_pos",                F(ARB_window_pos) },
    { OFF, "GL_NV_blend_square",                F(NV_blend_square) },
diff --git a/src/mesa/main/histogram.c b/src/mesa/main/histogram.c
index 905c1ad830..febf8d99c4 100644
--- a/src/mesa/main/histogram.c
+++ b/src/mesa/main/histogram.c
@@ -684,7 +684,7 @@ _mesa_GetMinmax(GLenum target, GLboolean reset, GLenum format, GLenum type, GLvo
       minmax[1][BCOMP] = CLAMP(ctx->MinMax.Max[BCOMP], 0.0F, 1.0F);
       minmax[1][ACOMP] = CLAMP(ctx->MinMax.Max[ACOMP], 0.0F, 1.0F);
       _mesa_pack_rgba_span_float(ctx, 2, minmax,
-                                 format, type, values, &ctx->Pack, 0x0);
+                                 format, type, values, &ctx->Pack, 0x0, GL_FALSE);
    }
 
    if (ctx->Pack.BufferObj->Name) {
diff --git a/src/mesa/main/image.c b/src/mesa/main/image.c
index fa3149d56d..44972ae8e2 100644
--- a/src/mesa/main/image.c
+++ b/src/mesa/main/image.c
@@ -1686,24 +1686,13 @@ _mesa_pack_rgba_span_float(GLcontext *ctx, GLuint n, GLfloat rgba[][4],
                            GLenum dstFormat, GLenum dstType,
                            GLvoid *dstAddr,
                            const struct gl_pixelstore_attrib *dstPacking,
-                           GLbitfield transferOps)
+                           GLbitfield transferOps, GLboolean noClamp)
 {
    GLfloat luminance[MAX_WIDTH];
    const GLint comps = _mesa_components_in_format(dstFormat);
    GLuint i;
-   /* clamping only applies to colors, not the dudv values, but still need
-      it if converting to unsigned values (which doesn't make much sense) */
-   if (dstFormat == GL_DUDV_ATI || dstFormat == GL_DU8DV8_ATI) {
-      switch (dstType) {
-         case GL_UNSIGNED_BYTE:
-         case GL_UNSIGNED_SHORT:
-         case GL_UNSIGNED_INT:
-            transferOps |= IMAGE_CLAMP_BIT;
-            break;
-            /* actually might want clamp to [-1,1] otherwise but shouldn't matter? */
-      }
-   }
-   else if (dstType != GL_FLOAT || ctx->Color.ClampReadColor == GL_TRUE) {
+
+   if ((!noClamp) && (dstType != GL_FLOAT || ctx->Color.ClampReadColor == GL_TRUE)) {
       /* need to clamp to [0, 1] */
       transferOps |= IMAGE_CLAMP_BIT;
    }
diff --git a/src/mesa/main/image.h b/src/mesa/main/image.h
index b26c27e5a8..fb7a5c0e90 100644
--- a/src/mesa/main/image.h
+++ b/src/mesa/main/image.h
@@ -178,7 +178,7 @@ extern void
 _mesa_pack_rgba_span_float( GLcontext *ctx, GLuint n, GLfloat rgba[][4],
                             GLenum dstFormat, GLenum dstType, GLvoid *dstAddr,
                             const struct gl_pixelstore_attrib *dstPacking,
-                            GLbitfield transferOps );
+                            GLbitfield transferOps, GLboolean noClamp );
 
 
 extern void
diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index bfd740870e..01d59dd42d 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -54,12 +54,20 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 #define FLOAT_TO_BYTE(X)    ( (((GLint) (255.0F * (X))) - 1) / 2 )
 
 
+/** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0], texture/fb data */
+#define BYTE_TO_FLOAT_TEX(B)    ((B) == -128 ? -1.0 : (B) * (1.0F/127.0F))
+
+/** Convert GLfloat in [-1.0,1.0] to GLbyte in [-128,127], texture/fb data */
+#define FLOAT_TO_BYTE_TEX(X)    ( (GLint) (127.0F * (X)) )
+
+
 /** Convert GLushort in [0,65535] to GLfloat in [0.0,1.0] */
 #define USHORT_TO_FLOAT(S)  ((GLfloat) (S) * (1.0F / 65535.0F))
 
 /** Convert GLfloat in [0.0,1.0] to GLushort in [0, 65535] */
 #define FLOAT_TO_USHORT(X)   ((GLuint) ((X) * 65535.0))
 
+
 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0] */
 #define SHORT_TO_FLOAT(S)   ((2.0F * (S) + 1.0F) * (1.0F/65535.0F))
 
@@ -67,6 +75,13 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 #define FLOAT_TO_SHORT(X)   ( (((GLint) (65535.0F * (X))) - 1) / 2 )
 
 
+/** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0], texture/fb data */
+#define SHORT_TO_FLOAT_TEX(S)    ((S) == -32768 ? -1.0 : (S) * (1.0F/32767.0F))
+
+/** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767], texture/fb data */
+#define FLOAT_TO_SHORT_TEX(X)    ( (GLint) (32767.0F * (X)) )
+
+
 /** Convert GLuint in [0,4294967295] to GLfloat in [0.0,1.0] */
 #define UINT_TO_FLOAT(U)    ((GLfloat) (U) * (1.0F / 4294967295.0F))
 
@@ -85,6 +100,13 @@ extern GLfloat _mesa_ubyte_to_float_color_tab[256];
 #define FLOAT_TO_INT(X)     ( (GLint) (2147483647.0 * (X)) )
 
 
+/** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0], texture/fb data */
+#define INT_TO_FLOAT_TEX(I)    ((I) == -2147483648 ? -1.0 : (I) * (1.0F/2147483647.0))
+
+/** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647], texture/fb data */
+#define FLOAT_TO_INT_TEX(X)    ( (GLint) (2147483647.0F * (X)) )
+
+
 #define BYTE_TO_UBYTE(b)   ((GLubyte) ((b) < 0 ? 0 : (GLubyte) (b)))
 #define SHORT_TO_UBYTE(s)  ((GLubyte) ((s) < 0 ? 0 : (GLubyte) ((s) >> 7)))
 #define USHORT_TO_UBYTE(s) ((GLubyte) ((s) >> 8))
diff --git a/src/mesa/main/mipmap.c b/src/mesa/main/mipmap.c
index 4a79430c34..7001211a13 100644
--- a/src/mesa/main/mipmap.c
+++ b/src/mesa/main/mipmap.c
@@ -86,6 +86,21 @@ bytes_per_pixel(GLenum datatype, GLuint comps)
                                 rowD[j][e], rowD[k][e]); \
    } while(0)
 
+#define FILTER_SUM_3D_SIGNED(Aj, Ak, Bj, Bk, Cj, Ck, Dj, Dk) \
+   (Aj + Ak \
+    + Bj + Bk \
+    + Cj + Ck \
+    + Dj + Dk \
+    + 4) / 8
+
+#define FILTER_3D_SIGNED(e) \
+   do { \
+      dst[i][e] = FILTER_SUM_3D_SIGNED(rowA[j][e], rowA[k][e], \
+                                       rowB[j][e], rowB[k][e], \
+                                       rowC[j][e], rowC[k][e], \
+                                       rowD[j][e], rowD[k][e]); \
+   } while(0)
+
 #define FILTER_F_3D(e) \
    do { \
       dst[i][e] = (rowA[j][e] + rowA[k][e] \
@@ -180,6 +195,53 @@ do_row(GLenum datatype, GLuint comps, GLint srcWidth,
       }
    }
 
+   if (datatype == GL_BYTE && comps == 4) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[4] = (const GLbyte(*)[4]) srcRowA;
+      const GLbyte(*rowB)[4] = (const GLbyte(*)[4]) srcRowB;
+      GLbyte(*dst)[4] = (GLbyte(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+         dst[i][3] = (rowA[j][3] + rowA[k][3] + rowB[j][3] + rowB[k][3]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 3) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[3] = (const GLbyte(*)[3]) srcRowA;
+      const GLbyte(*rowB)[3] = (const GLbyte(*)[3]) srcRowB;
+      GLbyte(*dst)[3] = (GLbyte(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 2) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[2] = (const GLbyte(*)[2]) srcRowA;
+      const GLbyte(*rowB)[2] = (const GLbyte(*)[2]) srcRowB;
+      GLbyte(*dst)[2] = (GLbyte(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 1) {
+      GLuint i, j, k;
+      const GLbyte *rowA = (const GLbyte *) srcRowA;
+      const GLbyte *rowB = (const GLbyte *) srcRowB;
+      GLbyte *dst = (GLbyte *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) / 4;
+      }
+   }
+
    else if (datatype == GL_UNSIGNED_SHORT && comps == 4) {
       GLuint i, j, k;
       const GLushort(*rowA)[4] = (const GLushort(*)[4]) srcRowA;
@@ -470,17 +532,6 @@ do_row(GLenum datatype, GLuint comps, GLint srcWidth,
          dst[i] = (blue << 5) | (green << 2) | red;
       }
    }
-   else if (datatype == GL_BYTE && comps == 2) {
-      GLuint i, j, k;
-      const GLbyte(*rowA)[2] = (const GLbyte(*)[2]) srcRowA;
-      const GLbyte(*rowB)[2] = (const GLbyte(*)[2]) srcRowB;
-      GLbyte(*dst)[2] = (GLbyte(*)[2]) dstRow;
-      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
-           i++, j += colStride, k += colStride) {
-         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) >> 2;
-         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) >> 2;
-      }
-   }
    else {
       _mesa_problem(NULL, "bad format in do_row()");
    }
@@ -555,6 +606,44 @@ do_row_3D(GLenum datatype, GLuint comps, GLint srcWidth,
          FILTER_3D(0);
       }
    }
+   if ((datatype == GL_BYTE) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLbyte, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+         FILTER_3D_SIGNED(2);
+         FILTER_3D_SIGNED(3);
+      }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLbyte, 3);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+         FILTER_3D_SIGNED(2);
+      }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLbyte, 2);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+       }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLbyte, 1);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+      }
+   }
    else if ((datatype == GL_UNSIGNED_SHORT) && (comps == 4)) {
       DECLARE_ROW_POINTERS(GLushort, 4);
 
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 5293009454..a5d3be3543 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2503,6 +2503,7 @@ struct gl_extensions
    GLboolean MESA_resize_buffers;
    GLboolean MESA_ycbcr_texture;
    GLboolean MESA_texture_array;
+   GLboolean MESA_texture_signed_rgba;
    GLboolean NV_blend_square;
    GLboolean NV_fragment_program;
    GLboolean NV_light_max_exponent;
diff --git a/src/mesa/main/texformat.c b/src/mesa/main/texformat.c
index c372b49398..0ceaaf3ece 100644
--- a/src/mesa/main/texformat.c
+++ b/src/mesa/main/texformat.c
@@ -699,9 +699,7 @@ const struct gl_texture_format _mesa_texformat_intensity_float16 = {
 const struct gl_texture_format _mesa_texformat_dudv8 = {
    MESA_FORMAT_DUDV8,			/* MesaFormat */
    GL_DUDV_ATI,				/* BaseFormat */
-   /* FIXME: spec doesn't say since that parameter didn't exist then,
-      but this should be something like SIGNED_NORMALIZED */
-   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
+   GL_SIGNED_NORMALIZED,		/* DataType */
    /* maybe should add dudvBits field, but spec seems to be
       lacking the ability to query with GetTexLevelParameter anyway */
    0,					/* RedBits */
@@ -724,6 +722,30 @@ const struct gl_texture_format _mesa_texformat_dudv8 = {
    NULL					/* StoreTexel */
 };
 
+const struct gl_texture_format _mesa_texformat_signed_rgba8888 = {
+   MESA_FORMAT_SIGNED_RGBA8888,		/* MesaFormat */
+   GL_RGBA,				/* BaseFormat */
+   GL_SIGNED_NORMALIZED,		/* DataType */
+   8,					/* RedBits */
+   8,					/* GreenBits */
+   8,					/* BlueBits */
+   8,					/* AlphaBits */
+   0,					/* LuminanceBits */
+   0,					/* IntensityBits */
+   0,					/* IndexBits */
+   0,					/* DepthBits */
+   0,					/* StencilBits */
+   4,					/* TexelBytes */
+   _mesa_texstore_signed_rgba8888,	/* StoreTexImageFunc */
+   NULL,				/* FetchTexel1D */
+   NULL,				/* FetchTexel2D */
+   NULL,				/* FetchTexel3D */
+   fetch_texel_1d_signed_rgba8888,	/* FetchTexel1Df */
+   fetch_texel_2d_signed_rgba8888,	/* FetchTexel2Df */
+   fetch_texel_3d_signed_rgba8888,	/* FetchTexel3Df */
+   store_texel_signed_rgba8888		/* StoreTexel */
+};
+
 /*@}*/
 
 
@@ -1671,6 +1693,17 @@ _mesa_choose_tex_format( GLcontext *ctx, GLint internalFormat,
       }
    }
 
+   if (ctx->Extensions.MESA_texture_signed_rgba) {
+      switch (internalFormat) {
+         case GL_RGBA_SNORM:
+         case GL_RGBA8_SNORM:
+            return &_mesa_texformat_signed_rgba8888;
+         default:
+            ; /* fallthrough */
+      }
+   }
+
+
 #if FEATURE_EXT_texture_sRGB
    if (ctx->Extensions.EXT_texture_sRGB) {
       switch (internalFormat) {
@@ -1820,6 +1853,11 @@ _mesa_format_to_type_and_comps(const struct gl_texture_format *format,
       *comps = 2;
       return;
 
+   case MESA_FORMAT_SIGNED_RGBA8888:
+      *datatype = GL_BYTE;
+      *comps = 4;
+      return;
+
 #if FEATURE_EXT_texture_sRGB
    case MESA_FORMAT_SRGB8:
       *datatype = GL_UNSIGNED_BYTE;
diff --git a/src/mesa/main/texformat.h b/src/mesa/main/texformat.h
index 7fa70ad4fe..3a08339adf 100644
--- a/src/mesa/main/texformat.h
+++ b/src/mesa/main/texformat.h
@@ -168,7 +168,8 @@ enum _format {
     * \name Signed fixed point texture formats.
     */
    /*@{*/
-   MESA_FORMAT_DUDV8
+   MESA_FORMAT_DUDV8,
+   MESA_FORMAT_SIGNED_RGBA8888
    /*@}*/
 };
 
@@ -219,6 +220,7 @@ extern const struct gl_texture_format _mesa_texformat_intensity_float16;
 /** Signed fixed point texture formats */
 /*@{*/
 extern const struct gl_texture_format _mesa_texformat_dudv8;
+extern const struct gl_texture_format _mesa_texformat_signed_rgba8888;
 /*@}*/
 
 /** \name Assorted hardware-friendly formats */
diff --git a/src/mesa/main/texformat_tmp.h b/src/mesa/main/texformat_tmp.h
index 0f6a172ef0..604b1a744c 100644
--- a/src/mesa/main/texformat_tmp.h
+++ b/src/mesa/main/texformat_tmp.h
@@ -1321,6 +1321,28 @@ static void FETCH(dudv8)(const struct gl_texture_image *texImage,
    texel[ACOMP] = 0;
 }
 
+/* MESA_FORMAT_SIGNED_ARGB8888 ***********************************************/
+
+static void FETCH(signed_rgba8888)( const struct gl_texture_image *texImage,
+			            GLint i, GLint j, GLint k, GLfloat *texel )
+{
+   const GLuint s = *TEXEL_ADDR(GLuint, texImage, i, j, k, 1);
+   texel[RCOMP] = BYTE_TO_FLOAT_TEX( (s >> 24)        );
+   texel[GCOMP] = BYTE_TO_FLOAT_TEX( (s >> 16) & 0xff );
+   texel[BCOMP] = BYTE_TO_FLOAT_TEX( (s >>  8) & 0xff );
+   texel[ACOMP] = BYTE_TO_FLOAT_TEX( (s      ) & 0xff );
+}
+
+#if DIM == 3
+static void store_texel_signed_rgba8888(struct gl_texture_image *texImage,
+                                        GLint i, GLint j, GLint k, const void *texel)
+{
+   const GLbyte *rgba = (const GLbyte *) texel;
+   GLuint *dst = TEXEL_ADDR(GLuint, texImage, i, j, k, 1);
+   *dst = PACK_COLOR_8888(rgba[RCOMP], rgba[GCOMP], rgba[BCOMP], rgba[ACOMP]);
+}
+#endif
+
 
 /* MESA_FORMAT_YCBCR *********************************************************/
 
diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index 4f297738df..8c03c36c75 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -349,6 +349,15 @@ _mesa_base_tex_format( GLcontext *ctx, GLint internalFormat )
       }
    }
 
+   if (ctx->Extensions.MESA_texture_signed_rgba) {
+      switch (internalFormat) {
+         case GL_RGBA_SNORM:
+         case GL_RGBA8_SNORM:
+            return GL_RGBA;
+         default:
+            ; /* fallthrough */
+      }
+   }
 
    if (ctx->Extensions.EXT_packed_depth_stencil) {
       switch (internalFormat) {
@@ -502,6 +511,10 @@ _mesa_is_color_format(GLenum format)
       case GL_COMPRESSED_SLUMINANCE_ALPHA_EXT:
 #endif /* FEATURE_EXT_texture_sRGB */
          return GL_TRUE;
+      /* signed texture formats */
+      case GL_RGBA_SNORM:
+      case GL_RGBA8_SNORM:
+         return GL_TRUE;
       case GL_YCBCR_MESA:  /* not considered to be RGB */
          /* fall-through */
       default:
diff --git a/src/mesa/main/texstore.c b/src/mesa/main/texstore.c
index cc3c6958c7..785fb50622 100644
--- a/src/mesa/main/texstore.c
+++ b/src/mesa/main/texstore.c
@@ -417,7 +417,7 @@ make_temp_float_image(GLcontext *ctx, GLuint dims,
                                           (GLfloat (*)[4]) src,
                                           logicalBaseFormat, GL_FLOAT,
                                           dst, &ctx->DefaultPacking,
-                                          postConvTransferOps);
+                                          postConvTransferOps, GL_FALSE);
                src += convWidth * 4;
                dst += convWidth * logComponents;
             }
@@ -798,6 +798,7 @@ static const GLubyte *
 type_mapping( GLenum srcType )
 {
    switch (srcType) {
+   case GL_BYTE:
    case GL_UNSIGNED_BYTE:
       return map_identity;
    case GL_UNSIGNED_INT_8_8_8_8:
@@ -819,6 +820,7 @@ byteswap_mapping( GLboolean swapBytes,
       return map_identity;
 
    switch (srcType) {
+   case GL_BYTE:
    case GL_UNSIGNED_BYTE:
       return map_identity;
    case GL_UNSIGNED_INT_8_8_8_8:
@@ -2561,6 +2563,99 @@ _mesa_texstore_dudv8(TEXSTORE_PARAMS)
    return GL_TRUE;
 }
 
+/**
+ * Store a texture in MESA_FORMAT_RGBA8888 or MESA_FORMAT_RGBA8888_REV.
+ */
+GLboolean
+_mesa_texstore_signed_rgba8888(TEXSTORE_PARAMS)
+{
+   const GLboolean littleEndian = _mesa_little_endian();
+
+   ASSERT(dstFormat == &_mesa_texformat_signed_rgba8888);
+   ASSERT(dstFormat->TexelBytes == 4);
+
+   if (!ctx->_ImageTransferState &&
+       !srcPacking->SwapBytes &&
+       dstFormat == &_mesa_texformat_signed_rgba8888 &&
+       baseInternalFormat == GL_RGBA &&
+      ((srcFormat == GL_RGBA && srcType == GL_BYTE && !littleEndian) ||
+       (srcFormat == GL_ABGR_EXT && srcType == GL_BYTE && littleEndian))) {
+       /* simple memcpy path */
+      memcpy_texture(ctx, dims,
+                     dstFormat, dstAddr, dstXoffset, dstYoffset, dstZoffset,
+                     dstRowStride,
+                     dstImageOffsets,
+                     srcWidth, srcHeight, srcDepth, srcFormat, srcType,
+                     srcAddr, srcPacking);
+   }
+   else if (!ctx->_ImageTransferState &&
+	    (srcType == GL_BYTE) &&
+	    can_swizzle(baseInternalFormat) &&
+	    can_swizzle(srcFormat)) {
+
+      GLubyte dstmap[4];
+
+      /* dstmap - how to swizzle from RGBA to dst format:
+       */
+      if (littleEndian && dstFormat == &_mesa_texformat_signed_rgba8888) {
+	 dstmap[3] = 0;
+	 dstmap[2] = 1;
+	 dstmap[1] = 2;
+	 dstmap[0] = 3;
+      }
+      else {
+	 dstmap[3] = 3;
+	 dstmap[2] = 2;
+	 dstmap[1] = 1;
+	 dstmap[0] = 0;
+      }
+      
+      _mesa_swizzle_ubyte_image(ctx, dims,
+				srcFormat,
+				srcType,
+				baseInternalFormat,
+				dstmap, 4,
+				dstAddr, dstXoffset, dstYoffset, dstZoffset,
+				dstRowStride, dstImageOffsets,
+				srcWidth, srcHeight, srcDepth, srcAddr,
+				srcPacking);      
+   }
+   else {
+      /* general path */
+      const GLfloat *tempImage = make_temp_float_image(ctx, dims,
+                                                 baseInternalFormat,
+                                                 dstFormat->BaseFormat,
+                                                 srcWidth, srcHeight, srcDepth,
+                                                 srcFormat, srcType, srcAddr,
+                                                 srcPacking);
+      const GLfloat *srcRow = tempImage;
+      GLint img, row, col;
+      if (!tempImage)
+         return GL_FALSE;
+      _mesa_adjust_image_for_convolution(ctx, dims, &srcWidth, &srcHeight);
+      for (img = 0; img < srcDepth; img++) {
+         GLubyte *dstRow = (GLubyte *) dstAddr
+            + dstImageOffsets[dstZoffset + img] * dstFormat->TexelBytes
+            + dstYoffset * dstRowStride
+            + dstXoffset * dstFormat->TexelBytes;
+         for (row = 0; row < srcHeight; row++) {
+            GLuint *dstUI = (GLuint *) dstRow;
+            if (dstFormat == &_mesa_texformat_signed_rgba8888) {
+               for (col = 0; col < srcWidth; col++) {
+                  dstUI[col] = PACK_COLOR_8888( FLOAT_TO_BYTE_TEX(srcRow[RCOMP]),
+                                                FLOAT_TO_BYTE_TEX(srcRow[GCOMP]),
+                                                FLOAT_TO_BYTE_TEX(srcRow[BCOMP]),
+                                                FLOAT_TO_BYTE_TEX(srcRow[ACOMP]) );
+                  srcRow += 4;
+               }
+            }
+            dstRow += dstRowStride;
+         }
+      }
+      _mesa_free((void *) tempImage);
+   }
+   return GL_TRUE;
+}
 
 /**
  * Store a combined depth/stencil texture image.
@@ -3820,6 +3915,21 @@ linear_to_nonlinear(GLfloat cl)
 
 #endif /* FEATURE_EXT_texture_sRGB */
 
+static INLINE GLboolean
+type_with_negative_values(GLenum type)
+{
+    switch (type) {
+    case GL_BYTE:
+    case GL_SHORT:
+    case GL_INT:
+    case GL_FLOAT:
+    case GL_HALF_FLOAT_ARB:
+       return GL_TRUE;
+   default:
+      return GL_FALSE;
+    }
+}
+
 /**
  * This is the software fallback for Driver.GetTexImage().
  * All error checking will have been done before this routine is called.
@@ -3962,7 +4072,7 @@ _mesa_get_teximage(GLcontext *ctx, GLenum target, GLint level,
                }
                _mesa_pack_rgba_span_float(ctx, width, (GLfloat (*)[4]) rgba,
                                           format, type, dest,
-                                          &ctx->Pack, transferOps /*image xfer ops*/);
+                                          &ctx->Pack, transferOps, GL_TRUE);
             }
 #endif /* FEATURE_EXT_texture_sRGB */
             else {
@@ -3971,10 +4081,13 @@ _mesa_get_teximage(GLcontext *ctx, GLenum target, GLint level,
                GLint col;
                GLbitfield transferOps = 0x0;
 
-               if (type == GL_FLOAT && texImage->TexFormat->BaseFormat != GL_DUDV_ATI &&
-                   ((ctx->Color.ClampReadColor == GL_TRUE) ||
-                    (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
-                     texImage->TexFormat->DataType != GL_FLOAT)))
+               /* clamp does not apply to GetTexImage (final conversion)?
+                  Looks like we need clamp though when going from format containing
+                  negative values to unsigned format */
+
+               if (!type_with_negative_values(type) &&
+                   (texImage->TexFormat->DataType == GL_FLOAT ||
+                   texImage->TexFormat->DataType == GL_SIGNED_NORMALIZED))
                   transferOps |= IMAGE_CLAMP_BIT;
 
                for (col = 0; col < width; col++) {
@@ -4001,7 +4114,7 @@ _mesa_get_teximage(GLcontext *ctx, GLenum target, GLint level,
                }
                _mesa_pack_rgba_span_float(ctx, width, (GLfloat (*)[4]) rgba,
                                           format, type, dest,
-                                          &ctx->Pack, transferOps /*image xfer ops*/);
+                                          &ctx->Pack, transferOps, GL_TRUE);
             } /* format */
          } /* row */
       } /* img */
diff --git a/src/mesa/main/texstore.h b/src/mesa/main/texstore.h
index c9e639be4e..91cb64f377 100644
--- a/src/mesa/main/texstore.h
+++ b/src/mesa/main/texstore.h
@@ -79,6 +79,7 @@ extern GLboolean _mesa_texstore_sl8(TEXSTORE_PARAMS);
 extern GLboolean _mesa_texstore_sla8(TEXSTORE_PARAMS);
 #endif
 extern GLboolean _mesa_texstore_dudv8(TEXSTORE_PARAMS);
+extern GLboolean _mesa_texstore_signed_rgba8888(TEXSTORE_PARAMS);
 
 extern GLchan *
 _mesa_make_temp_chan_image(GLcontext *ctx, GLuint dims,
diff --git a/src/mesa/state_tracker/st_cb_readpixels.c b/src/mesa/state_tracker/st_cb_readpixels.c
index ce7a8cda4e..c11973cdb3 100644
--- a/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/src/mesa/state_tracker/st_cb_readpixels.c
@@ -486,7 +486,7 @@ st_readpixels(GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
             df += dfStride;
             if (!dfStride) {
                _mesa_pack_rgba_span_float(ctx, width, temp, format, type, dst,
-                                          &clippedPacking, transferOps);
+                                          &clippedPacking, transferOps, GL_FALSE);
                dst += dstStride;
             }
          }
diff --git a/src/mesa/swrast/s_readpix.c b/src/mesa/swrast/s_readpix.c
index e901fc6b5d..524ac4ee21 100644
--- a/src/mesa/swrast/s_readpix.c
+++ b/src/mesa/swrast/s_readpix.c
@@ -396,7 +396,7 @@ read_rgba_pixels( GLcontext *ctx,
                                       format, type, row, 0);
          _mesa_pack_rgba_span_float(ctx, width, (GLfloat (*)[4]) src,
                                     format, type, dest, packing,
-                                    transferOps & IMAGE_POST_CONVOLUTION_BITS);
+                                    transferOps & IMAGE_POST_CONVOLUTION_BITS, GL_FALSE);
          src += width * 4;
       }
       _mesa_free(convImage);
@@ -441,7 +441,7 @@ read_rgba_pixels( GLcontext *ctx,
 
          /* pack the row of RGBA pixels into user's buffer */
          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
-                                    packing, transferOps);
+                                    packing, transferOps, GL_FALSE);
 
          dst += dstStride;
       }