[Mesa-dev] [PATCH] mesa/llvmpipe: add fake MSAA support

[Dave Airlie]

This adds a gallium cap that allows us to fake GL3.0 by
not exposing MSAA on sw rendering. It also forces the
extra extensions needed for GL3.2. Along with a patch to
raise the GLSL version in llvmpipe this will expose GL3.3
on llvmpipe.

However we still need Marek's code for layered clears.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/drivers/llvmpipe/lp_screen.c | 2 ++
 src/gallium/include/pipe/p_defines.h     | 3 ++-
 src/mesa/main/mtypes.h                   | 1 +
 src/mesa/main/version.c                  | 2 +-
 src/mesa/state_tracker/st_extensions.c   | 7 +++++++
 5 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
index f61df98..218b3f8 100644
--- a/src/gallium/drivers/llvmpipe/lp_screen.c
+++ b/src/gallium/drivers/llvmpipe/lp_screen.c
@@ -234,6 +234,8 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
       return PIPE_MAX_VIEWPORTS;
    case PIPE_CAP_ENDIANNESS:
       return PIPE_ENDIAN_NATIVE;
+   case PIPE_CAP_FAKE_SW_MSAA:
+	return 1;
    }
    /* should only get here on unhandled cases */
    debug_printf("Unexpected PIPE_CAP %d query\n", param);
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index db6db32..27f1bcf 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -513,7 +513,8 @@ enum pipe_cap {
    PIPE_CAP_MAX_TEXTURE_BUFFER_SIZE = 83,
    PIPE_CAP_MAX_VIEWPORTS = 84,
    PIPE_CAP_ENDIANNESS = 85,
-   PIPE_CAP_MIXED_FRAMEBUFFER_SIZES = 86
+   PIPE_CAP_MIXED_FRAMEBUFFER_SIZES = 86,
+   PIPE_CAP_FAKE_SW_MSAA = 87
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index ecfb5e0..39b8abd 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3302,6 +3302,7 @@ struct gl_constants
    /** GL_ARB_vertex_attrib_binding */
    GLint MaxVertexAttribRelativeOffset;
    GLint MaxVertexAttribBindings;
+   GLboolean FakeSWMSAA;
 };
 
 
diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
index 55411fa..1dfce09 100644
--- a/src/mesa/main/version.c
+++ b/src/mesa/main/version.c
@@ -229,7 +229,7 @@ compute_version(struct gl_context *ctx)
                               ctx->Extensions.EXT_texture_sRGB);
    const GLboolean ver_3_0 = (ver_2_1 &&
                               ctx->Const.GLSLVersion >= 130 &&
-                              ctx->Const.MaxSamples >= 4 &&
+                              (ctx->Const.MaxSamples >= 4 || ctx->Const.FakeSWMSAA) &&
                               (ctx->API == API_OPENGL_CORE ||
                                ctx->Extensions.ARB_color_buffer_float) &&
                               ctx->Extensions.ARB_depth_buffer_float &&
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index cd10a0c..701086a 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -715,6 +715,13 @@ void st_init_extensions(struct st_context *st)
       ctx->Extensions.EXT_framebuffer_multisample_blit_scaled = GL_TRUE;
    }
 
+   if (ctx->Const.MaxSamples == 0 && screen->get_param(screen, PIPE_CAP_FAKE_SW_MSAA)) {
+	ctx->Const.FakeSWMSAA = GL_TRUE;
+        ctx->Extensions.EXT_framebuffer_multisample = GL_TRUE;
+        ctx->Extensions.EXT_framebuffer_multisample_blit_scaled = GL_TRUE;
+        ctx->Extensions.ARB_texture_multisample = GL_TRUE;
+   }
+
    if (ctx->Const.MaxDualSourceDrawBuffers > 0 &&
        !st->options.disable_blend_func_extended)
       ctx->Extensions.ARB_blend_func_extended = GL_TRUE;
-- 
1.8.3.1