diff --git a/src/vrend_renderer.c b/src/vrend_renderer.c
index a325f9e..2103f66 100644
--- a/src/vrend_renderer.c
+++ b/src/vrend_renderer.c
@@ -2804,6 +2804,7 @@ static inline void vrend_fill_shader_key(struct vrend_context *ctx,
    }
    key->invert_fs_origin = !ctx->sub->inverted_fbo_content;
    key->coord_replace = ctx->sub->rs_state.point_quad_rasterization ? ctx->sub->rs_state.sprite_coord_enable : 0;
+   key->winsys_adjust_y_emitted = false;
 
    if (ctx->sub->shaders[PIPE_SHADER_GEOMETRY])
       key->gs_present = true;
diff --git a/src/vrend_shader.c b/src/vrend_shader.c
index a3e3b01..08053b9 100644
--- a/src/vrend_shader.c
+++ b/src/vrend_shader.c
@@ -4613,8 +4613,10 @@ static char *emit_ios(struct dump_ctx *ctx, char *glsl_hdr)
       }
 
       if (ctx->prog_type == TGSI_PROCESSOR_FRAGMENT && ctx->cfg->use_gles &&
+          !ctx->key->winsys_adjust_y_emitted &&
          (ctx->key->coord_replace & (1 << ctx->inputs[i].sid))) {
          snprintf(buf, 255, "uniform float winsys_adjust_y;\n");
+         ctx->key->winsys_adjust_y_emitted = true;
          STRCAT_WITH_RET(glsl_hdr, buf);
       }
    }
diff --git a/src/vrend_shader.h b/src/vrend_shader.h
index fbcdf63..cb928e6 100644
--- a/src/vrend_shader.h
+++ b/src/vrend_shader.h
@@ -82,6 +82,7 @@ struct vrend_shader_info {
 
 struct vrend_shader_key {
    uint32_t coord_replace;
+   bool winsys_adjust_y_emitted;
    bool invert_fs_origin;
    bool pstipple_tex;
    bool add_alpha_test;