zink - Fix for blend color change without blend state change

Flag blend color change and make sure vkCmdSetBlendConstants is called.

Signed-off-by: daoxianggong <daoxiang.gong@imgtec.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26799>

src/gallium/drivers/zink/zink_context.c

@@ -3713,6 +3713,8 @@ zink_set_blend_color(struct pipe_context *pctx,
 {
    struct zink_context *ctx = zink_context(pctx);
    memcpy(ctx->blend_constants, color->color, sizeof(float) * 4);
+
+   ctx->blend_color_changed = true;
    zink_flush_dgc_if_enabled(ctx);
 }
 

src/gallium/drivers/zink/zink_draw.cpp

@@ -874,10 +874,11 @@ zink_draw(struct pipe_context *pctx,
       ctx->sample_locations_changed = false;
    }
 
-   if (BATCH_CHANGED || ctx->blend_state_changed) {
+   if (BATCH_CHANGED || ctx->blend_color_changed) {
       VKCTX(CmdSetBlendConstants)(batch->state->cmdbuf, ctx->blend_constants);
    }
    ctx->blend_state_changed = false;
+   ctx->blend_color_changed = false;
 
    if (!DRAW_STATE) {
       if (BATCH_CHANGED || ctx->vertex_buffers_dirty) {

src/gallium/drivers/zink/zink_types.h

@@ -2032,6 +2032,7 @@ struct zink_context {
    bool unordered_blitting : 1;
    bool vertex_state_changed : 1;
    bool blend_state_changed : 1;
+   bool blend_color_changed : 1;
    bool sample_mask_changed : 1;
    bool rast_state_changed : 1;
    bool line_width_changed : 1;