Expose currently selected shader via poke interface.

driver.h

@@ -358,6 +358,8 @@ typedef struct video_poke_interface
 
    void (*show_mouse)(void *data, bool state);
    void (*grab_mouse_toggle)(void *data);
+
+   struct gfx_shader *(*get_current_shader)(void *data);
 } video_poke_interface_t;
 
 typedef struct video_driver

gfx/gl.c

@@ -2909,6 +2909,12 @@ static void gl_show_mouse(void *data, bool state)
       gl->ctx_driver->show_mouse(gl, state);
 }
 
+static struct gfx_shader *gl_get_current_shader(void *data)
+{
+   gl_t *gl = (gl_t*)data;
+   return gl->shader ? gl->shader->get_current_shader() : NULL;
+}
+
 static const video_poke_interface_t gl_poke_interface = {
    NULL,
 #ifdef HAVE_FBO
@@ -2924,6 +2930,9 @@ static const video_poke_interface_t gl_poke_interface = {
    gl_set_osd_msg,
 
    gl_show_mouse,
+   NULL,
+
+   gl_get_current_shader,
 };
 
 static void gl_get_poke_interface(void *data, const video_poke_interface_t **iface)

gfx/shader_cg.c

@@ -913,6 +913,11 @@ static bool gl_cg_mipmap_input(unsigned index)
       return false;
 }
 
+static struct gfx_shader *gl_cg_get_current_shader(void)
+{
+   return cg_active ? cg_shader : NULL;
+}
+
 void gl_cg_invalidate_context(void)
 {
    cgCtx = NULL;
@@ -931,6 +936,7 @@ const gl_shader_backend_t gl_cg_backend = {
    gl_cg_set_mvp,
    gl_cg_get_prev_textures,
    gl_cg_mipmap_input,
+   gl_cg_get_current_shader,
 
    RARCH_SHADER_CG,
 };

gfx/shader_common.h

@@ -54,6 +54,8 @@ struct gl_shader_backend
    unsigned (*get_prev_textures)(void);
    bool (*mipmap_input)(unsigned index);
 
+   struct gfx_shader *(*get_current_shader)(void);
+
    enum rarch_shader_type type;
 };
 

gfx/shader_glsl.c

@@ -1179,6 +1179,11 @@ static bool gl_glsl_mipmap_input(unsigned index)
       return false;
 }
 
+static struct gfx_shader *gl_glsl_get_current_shader(void)
+{
+   return glsl_enable ? glsl_shader : NULL;
+}
+
 void gl_glsl_set_get_proc_address(gfx_ctx_proc_t (*proc)(const char*))
 {
    glsl_get_proc_address = proc;
@@ -1204,6 +1209,7 @@ const gl_shader_backend_t gl_glsl_backend = {
    gl_glsl_set_mvp,
    gl_glsl_get_prev_textures,
    gl_glsl_mipmap_input,
+   gl_glsl_get_current_shader,
 
    RARCH_SHADER_GLSL,
 };

gfx/shader_hlsl.c

@@ -435,6 +435,11 @@ static bool hlsl_mipmap_input(unsigned index)
    return false;
 }
 
+static struct gfx_shader *hlsl_get_current_shader(void)
+{
+   return NULL;
+}
+
 const gl_shader_backend_t hlsl_backend = {
    hlsl_init,
    hlsl_deinit,
@@ -448,6 +453,7 @@ const gl_shader_backend_t hlsl_backend = {
    hlsl_set_mvp,
    NULL,              /* hlsl_get_prev_textures */
    hlsl_mipmap_input,
+   hlsl_get_current_shader,
 
    RARCH_SHADER_HLSL,
 };

gfx/video_thread_wrapper.c

@@ -751,6 +751,13 @@ static void thread_apply_state_changes(void *data)
    slock_unlock(thr->frame.lock);
 }
 
+// This is read-only state which should not have any kind of race condition.
+static struct gfx_shader *thread_get_current_shader(void *data)
+{
+   thread_video_t *thr = (thread_video_t*)data;
+   return thr->poke ? thr->poke->get_current_shader(thr->driver_data) : NULL;
+}
+
 static const video_poke_interface_t thread_poke = {
    thread_set_filtering,
 #ifdef HAVE_FBO
@@ -763,6 +770,12 @@ static const video_poke_interface_t thread_poke = {
    thread_set_texture_frame,
    thread_set_texture_enable,
 #endif
+
+   NULL,
+   NULL,
+   NULL,
+
+   thread_get_current_shader,
 };
 
 static void thread_get_poke_interface(void *data, const video_poke_interface_t **iface)