i915: Use L8A8 instead of I8 to simulate A8 on gen2

Gen2 doesn't support the A8 texture format. Currently the driver
substitutes it with I8, but that results in incorrect RGB values.
Use A8L8 instead. We end up wasting a bit of memory, but at least
we should get the correct results.

v2: Handle the fallback in _mesa_choose_tex_format() and also
    do it for all alpha formats that currently accept A8

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72819
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80050
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38873
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

diff --git a/src/mesa/drivers/dri/i915/i830_texstate.c b/src/mesa/drivers/dri/i915/i830_texstate.c
index 58d3356d6e427d7c16601165346e39c2282b2de5..b1414c7005bfe89d86f2ef1354be8556cedc1089 100644 (file)
--- a/src/mesa/drivers/dri/i915/i830_texstate.c
+++ b/src/mesa/drivers/dri/i915/i830_texstate.c
@@ -47,8 +47,6 @@ translate_texture_format(GLuint mesa_format)
       return MAPSURF_8BIT | MT_8BIT_L8;
    case MESA_FORMAT_I_UNORM8:
       return MAPSURF_8BIT | MT_8BIT_I8;
-   case MESA_FORMAT_A_UNORM8:
-      return MAPSURF_8BIT | MT_8BIT_I8; /* Kludge! */
    case MESA_FORMAT_L8A8_UNORM:
       return MAPSURF_16BIT | MT_16BIT_AY88;
    case MESA_FORMAT_B5G6R5_UNORM:

diff --git a/src/mesa/drivers/dri/i915/i915_context.c b/src/mesa/drivers/dri/i915/i915_context.c
index 8811e8d4e6d50109a7a24438f0dee8874baf9025..42ea54e087dc28cb6a73675905f1a1a41de09289 100644 (file)
--- a/src/mesa/drivers/dri/i915/i915_context.c
+++ b/src/mesa/drivers/dri/i915/i915_context.c
@@ -109,7 +109,8 @@ intel_init_texture_formats(struct gl_context *ctx)
    ctx->TextureFormatSupported[MESA_FORMAT_B5G5R5A1_UNORM] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_B5G6R5_UNORM] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_L_UNORM8] = true;
-   ctx->TextureFormatSupported[MESA_FORMAT_A_UNORM8] = true;
+   if (intel->gen == 3)
+      ctx->TextureFormatSupported[MESA_FORMAT_A_UNORM8] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_I_UNORM8] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_L8A8_UNORM] = true;
 

diff --git a/src/mesa/main/texformat.c b/src/mesa/main/texformat.c
index 832e66128d81de3eb326de4f54f236fd1609ffd5..ec16af9d2a19a3c2f43fa5b1c70b52768ece9d8c 100644 (file)
--- a/src/mesa/main/texformat.c
+++ b/src/mesa/main/texformat.c
@@ -155,12 +155,14 @@ _mesa_choose_tex_format(struct gl_context *ctx, GLenum target,
    case GL_ALPHA4:
    case GL_ALPHA8:
       RETURN_IF_SUPPORTED(MESA_FORMAT_A_UNORM8);
+      RETURN_IF_SUPPORTED(MESA_FORMAT_L8A8_UNORM);
       break;
 
    case GL_ALPHA12:
    case GL_ALPHA16:
       RETURN_IF_SUPPORTED(MESA_FORMAT_A_UNORM16);
       RETURN_IF_SUPPORTED(MESA_FORMAT_A_UNORM8);
+      RETURN_IF_SUPPORTED(MESA_FORMAT_L8A8_UNORM);
       break;
 
    /* Luminance formats */
@@ -224,6 +226,7 @@ _mesa_choose_tex_format(struct gl_context *ctx, GLenum target,
 
    case GL_COMPRESSED_ALPHA_ARB:
       RETURN_IF_SUPPORTED(MESA_FORMAT_A_UNORM8);
+      RETURN_IF_SUPPORTED(MESA_FORMAT_L8A8_UNORM);
       break;
    case GL_COMPRESSED_LUMINANCE_ARB:
       RETURN_IF_SUPPORTED(MESA_FORMAT_L_UNORM8);