Mesa (master): mesa: Keep a computed value for dual source blend func with each buffer.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 175ad8050e3337f7065306017ea4eb8eae599f6d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=175ad8050e3337f7065306017ea4eb8eae599f6d

Author: Eric Anholt <eric at anholt.net>
Date:   Thu May 17 15:31:40 2012 -0700

mesa: Keep a computed value for dual source blend func with each buffer.

The i965 driver needed this as well for hardware setup, so instead of
duplicating the logic, just save it off.

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Dave Airlie <airlied at redhat.com>

---

 src/mesa/main/blend.c   |   20 ++++++++++++++++++++
 src/mesa/main/context.c |   24 +++++++-----------------
 src/mesa/main/mtypes.h  |    5 +++++
 3 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/src/mesa/main/blend.c b/src/mesa/main/blend.c
index bc446ed..5bc40a0 100644
--- a/src/mesa/main/blend.c
+++ b/src/mesa/main/blend.c
@@ -166,6 +166,24 @@ _mesa_BlendFunc( GLenum sfactor, GLenum dfactor )
    _mesa_BlendFuncSeparateEXT(sfactor, dfactor, sfactor, dfactor);
 }
 
+static GLboolean
+blend_factor_is_dual_src(GLenum factor)
+{
+   return (factor == GL_SRC1_COLOR ||
+	   factor == GL_SRC1_ALPHA ||
+	   factor == GL_ONE_MINUS_SRC1_COLOR ||
+	   factor == GL_ONE_MINUS_SRC1_ALPHA);
+}
+
+static void
+update_uses_dual_src(struct gl_context *ctx, int buf)
+{
+   ctx->Color.Blend[buf]._UsesDualSrc =
+      (blend_factor_is_dual_src(ctx->Color.Blend[buf].SrcRGB) ||
+       blend_factor_is_dual_src(ctx->Color.Blend[buf].DstRGB) ||
+       blend_factor_is_dual_src(ctx->Color.Blend[buf].SrcA) ||
+       blend_factor_is_dual_src(ctx->Color.Blend[buf].DstA));
+}
 
 /**
  * Set the separate blend source/dest factors for all draw buffers.
@@ -220,6 +238,7 @@ _mesa_BlendFuncSeparateEXT( GLenum sfactorRGB, GLenum dfactorRGB,
       ctx->Color.Blend[buf].DstRGB = dfactorRGB;
       ctx->Color.Blend[buf].SrcA = sfactorA;
       ctx->Color.Blend[buf].DstA = dfactorA;
+      update_uses_dual_src(ctx, buf);
    }
    ctx->Color._BlendFuncPerBuffer = GL_FALSE;
 
@@ -282,6 +301,7 @@ _mesa_BlendFuncSeparatei(GLuint buf, GLenum sfactorRGB, GLenum dfactorRGB,
    ctx->Color.Blend[buf].DstRGB = dfactorRGB;
    ctx->Color.Blend[buf].SrcA = sfactorA;
    ctx->Color.Blend[buf].DstA = dfactorA;
+   update_uses_dual_src(ctx, buf);
    ctx->Color._BlendFuncPerBuffer = GL_TRUE;
 
    if (ctx->Driver.BlendFuncSeparatei) {
diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
index df0452c..3bcedec 100644
--- a/src/mesa/main/context.c
+++ b/src/mesa/main/context.c
@@ -1703,13 +1703,6 @@ _mesa_set_mvp_with_dp4( struct gl_context *ctx,
    ctx->mvp_with_dp4 = flag;
 }
 
-static GLboolean
-blend_factor_is_dual_src(GLenum factor)
-{
-   return factor == GL_SRC1_COLOR || factor == GL_SRC1_ALPHA ||
-      factor == GL_ONE_MINUS_SRC1_COLOR || factor == GL_ONE_MINUS_SRC1_ALPHA;
-}
-
 /*
  * ARB_blend_func_extended - ERRORS section
  * "The error INVALID_OPERATION is generated by Begin or any procedure that
@@ -1722,16 +1715,13 @@ static GLboolean
 _mesa_check_blend_func_error(struct gl_context *ctx)
 {
    GLuint i;
-   for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
-      if (blend_factor_is_dual_src(ctx->Color.Blend[i].SrcRGB) ||
-          blend_factor_is_dual_src(ctx->Color.Blend[i].DstRGB) ||
-          blend_factor_is_dual_src(ctx->Color.Blend[i].SrcA) ||
-          blend_factor_is_dual_src(ctx->Color.Blend[i].DstA)) {
-         if (i >= ctx->Const.MaxDualSourceDrawBuffers) {
-            _mesa_error(ctx, GL_INVALID_OPERATION,
-                        "dual source blend on illegal attachment");
-            return GL_FALSE;
-         }
+   for (i = ctx->Const.MaxDualSourceDrawBuffers;
+	i < ctx->DrawBuffer->_NumColorDrawBuffers;
+	i++) {
+      if (ctx->Color.Blend[i]._UsesDualSrc) {
+	 _mesa_error(ctx, GL_INVALID_OPERATION,
+		     "dual source blend on illegal attachment");
+	 return GL_FALSE;
       }
    }
    return GL_TRUE;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index eefe5e7..3a8cac9 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -755,6 +755,11 @@ struct gl_colorbuffer_attrib
       GLenum DstA;               /**< Alpha blend dest term */
       GLenum EquationRGB;        /**< GL_ADD, GL_SUBTRACT, etc. */
       GLenum EquationA;          /**< GL_ADD, GL_SUBTRACT, etc. */
+      /**
+       * Set if any blend factor uses SRC1.  Computed at the time blend factors
+       * get set.
+       */
+      GLboolean _UsesDualSrc;
    } Blend[MAX_DRAW_BUFFERS];
    /** Are the blend func terms currently different for each buffer/target? */
    GLboolean _BlendFuncPerBuffer;