From 175ad8050e3337f7065306017ea4eb8eae599f6d Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Thu, 17 May 2012 15:31:40 -0700
Subject: [PATCH] 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@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Dave Airlie <airlied@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 bc446edcabb..5bc40a028bd 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 df0452cd114..3bcedecd9ba 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 eefe5e7e97d..3a8cac9c5a1 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;
-- 
2.30.2