mesa: per-buffer blend enabled flags

ctx->Color.BlendEnabled is now a GLbitfield instead of a GLboolean to
indicate blend on/off status for each color/draw buffer.

This is infrastructure for GL_EXT_draw_buffers2 and OpenGL 3.x

New functions include _mesa_EnableIndexed(), _mesa_DisableIndexed(), and
_mesa_IsEnabledIndexed().  The enable function corresponds to
glEnableIndexedEXT() for GL_EXT_draw_buffers2 or glEnablei() for GL3.

Note that there's quite a few tests for ctx->Color.BlendEnabled != 0 in
drivers, etc.  Those tests can remain as-is since the mask will be 0 or ~0
unless GL_EXT_draw_buffers2 is enabled.

1 files changed, 13 insertions, 5 deletions

diff --git a/src/mesa/drivers/common/meta.c b/src/mesa/drivers/common/meta.c
index cd9075b3936..da2c06677a6 100644
--- a/src/mesa/drivers/common/meta.c
+++ b/src/mesa/drivers/common/meta.c
@@ -107,7 +107,7 @@ struct save_state
    GLboolean AlphaEnabled;
 
    /** META_BLEND */
-   GLboolean BlendEnabled;
+   GLbitfield BlendEnabled;
    GLboolean ColorLogicOpEnabled;
 
    /** META_COLOR_MASK */
@@ -335,8 +335,12 @@ _mesa_meta_begin(GLcontext *ctx, GLbitfield state)
 
    if (state & META_BLEND) {
       save->BlendEnabled = ctx->Color.BlendEnabled;
-      if (ctx->Color.BlendEnabled)
-         _mesa_set_enable(ctx, GL_BLEND, GL_FALSE);
+      if (ctx->Color.BlendEnabled) {
+         GLuint i;
+         for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) {
+            _mesa_set_enablei(ctx, GL_BLEND, i, GL_FALSE);
+         }
+      }
       save->ColorLogicOpEnabled = ctx->Color.ColorLogicOpEnabled;
       if (ctx->Color.ColorLogicOpEnabled)
          _mesa_set_enable(ctx, GL_COLOR_LOGIC_OP, GL_FALSE);
@@ -566,8 +570,12 @@ _mesa_meta_end(GLcontext *ctx)
    }
 
    if (state & META_BLEND) {
-      if (ctx->Color.BlendEnabled != save->BlendEnabled)
-         _mesa_set_enable(ctx, GL_BLEND, save->BlendEnabled);
+      if (ctx->Color.BlendEnabled != save->BlendEnabled) {
+         GLuint i;
+         for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) {
+            _mesa_set_enablei(ctx, GL_BLEND, i, (save->BlendEnabled >> i) & 1);
+         }
+      }
       if (ctx->Color.ColorLogicOpEnabled != save->ColorLogicOpEnabled)
          _mesa_set_enable(ctx, GL_COLOR_LOGIC_OP, save->ColorLogicOpEnabled);
    }