mesa: in glReadBufer() set _NEW_BUFFERS, not _NEW_PIXEL

Since GL_READ_BUFFER is historically part of the gl_pixel_attrib group
it made sense to signal changes with _NEW_PIXEL.  But now with FBOs it's
also part of the framebuffer state.

Now _NEW_PIXEL strictly indicates pixels transfer state changes.

This change avoids framebuffer state validation when any random bit of
pixel-transfer state is set.

DRI drivers updated too:  don't check _NEW_COLOR when updating framebuffer
state.  I think that was just copied from the Xlib driver because we care
about dither enable/disable state there.

6 files changed, 7 insertions, 6 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_buffers.c b/src/mesa/drivers/dri/intel/intel_buffers.c
index b86cafea24..4f4ea45b74 100644
--- a/src/mesa/drivers/dri/intel/intel_buffers.c
+++ b/src/mesa/drivers/dri/intel/intel_buffers.c
@@ -157,7 +157,7 @@ intel_draw_buffer(GLcontext * ctx, struct gl_framebuffer *fb)
    /* Do this here, not core Mesa, since this function is called from
     * many places within the driver.
     */
-   if (ctx->NewState & (_NEW_BUFFERS | _NEW_COLOR | _NEW_PIXEL)) {
+   if (ctx->NewState & _NEW_BUFFERS) {
       /* this updates the DrawBuffer->_NumColorDrawBuffers fields, etc */
       _mesa_update_framebuffer(ctx);
       /* this updates the DrawBuffer's Width/Height if it's a FBO */
diff --git a/src/mesa/drivers/dri/r200/r200_state.c b/src/mesa/drivers/dri/r200/r200_state.c
index 28ba5f49bc..81ee1ed022 100644
--- a/src/mesa/drivers/dri/r200/r200_state.c
+++ b/src/mesa/drivers/dri/r200/r200_state.c
@@ -2480,7 +2480,7 @@ void r200ValidateState( GLcontext *ctx )
    r200ContextPtr rmesa = R200_CONTEXT(ctx);
    GLuint new_state = rmesa->NewGLState;
 
-   if (new_state & (_NEW_BUFFERS | _NEW_COLOR | _NEW_PIXEL)) {
+   if (new_state & _NEW_BUFFERS) {
      r200UpdateDrawBuffer(ctx);
    }
 
diff --git a/src/mesa/drivers/dri/r300/r300_state.c b/src/mesa/drivers/dri/r300/r300_state.c
index b96ba4ed94..07299f3b36 100644
--- a/src/mesa/drivers/dri/r300/r300_state.c
+++ b/src/mesa/drivers/dri/r300/r300_state.c
@@ -2589,7 +2589,7 @@ static void r300InvalidateState(GLcontext * ctx, GLuint new_state)
 	_tnl_InvalidateState(ctx, new_state);
 	_ae_invalidate_state(ctx, new_state);
 
-	if (new_state & (_NEW_BUFFERS | _NEW_COLOR | _NEW_PIXEL)) {
+	if (new_state & _NEW_BUFFERS) {
 		r300UpdateDrawBuffer(ctx);
 	}
 
diff --git a/src/mesa/drivers/dri/radeon/radeon_state.c b/src/mesa/drivers/dri/radeon/radeon_state.c
index b6561001e7..4432f85691 100644
--- a/src/mesa/drivers/dri/radeon/radeon_state.c
+++ b/src/mesa/drivers/dri/radeon/radeon_state.c
@@ -2255,7 +2255,7 @@ void radeonValidateState( GLcontext *ctx )
    radeonContextPtr rmesa = RADEON_CONTEXT(ctx);
    GLuint new_state = rmesa->NewGLState;
 
-   if (new_state & (_NEW_BUFFERS | _NEW_COLOR | _NEW_PIXEL)) {
+   if (new_state & _NEW_BUFFERS) {
      radeonUpdateDrawBuffer(ctx);
    }
 
diff --git a/src/mesa/drivers/x11/xm_dd.c b/src/mesa/drivers/x11/xm_dd.c
index 305df548fa..9a01465bdf 100644
--- a/src/mesa/drivers/x11/xm_dd.c
+++ b/src/mesa/drivers/x11/xm_dd.c
@@ -912,8 +912,9 @@ xmesa_update_state( GLcontext *ctx, GLbitfield new_state )
    /*
     * GL_DITHER, GL_READ/DRAW_BUFFER, buffer binding state, etc. effect
     * renderbuffer span/clear funcs.
+    * Check _NEW_COLOR to detect dither enable/disable.
     */
-   if (new_state & (_NEW_COLOR | _NEW_PIXEL | _NEW_BUFFERS)) {
+   if (new_state & (_NEW_COLOR | _NEW_BUFFERS)) {
       XMesaBuffer xmbuf = XMESA_BUFFER(ctx->DrawBuffer);
       struct xmesa_renderbuffer *front_xrb, *back_xrb;
 
diff --git a/src/mesa/main/buffers.c b/src/mesa/main/buffers.c
index c5f13345f0..d8b5f3b1f4 100644
--- a/src/mesa/main/buffers.c
+++ b/src/mesa/main/buffers.c
@@ -443,7 +443,7 @@ _mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex)
    fb->ColorReadBuffer = buffer;
    fb->_ColorReadBufferIndex = bufferIndex;
 
-   ctx->NewState |= _NEW_PIXEL;
+   ctx->NewState |= _NEW_BUFFERS;
 }