diff --git a/gfx/shader_cg.c b/gfx/shader_cg.c
index 17c0196924..b599c292f4 100644
--- a/gfx/shader_cg.c
+++ b/gfx/shader_cg.c
@@ -104,10 +104,12 @@ struct cg_program
    CGparameter tex_size_f;
    CGparameter out_size_f;
    CGparameter frame_cnt_f;
+   CGparameter frame_dir_f;
    CGparameter vid_size_v;
    CGparameter tex_size_v;
    CGparameter out_size_v;
    CGparameter frame_cnt_v;
+   CGparameter frame_dir_v;
    CGparameter mvp;
 
    struct cg_fbo_params fbo[MAX_SHADERS];
@@ -162,11 +164,13 @@ void gl_cg_set_params(unsigned width, unsigned height,
       set_param_2f(prg[active_index].tex_size_f, tex_width, tex_height);
       set_param_2f(prg[active_index].out_size_f, out_width, out_height);
       set_param_1f(prg[active_index].frame_cnt_f, (float)frame_count);
+      set_param_1f(prg[active_index].frame_dir_f, g_extern.frame_is_reverse ? -1.0 : 1.0);
 
       set_param_2f(prg[active_index].vid_size_v, width, height);
       set_param_2f(prg[active_index].tex_size_v, tex_width, tex_height);
       set_param_2f(prg[active_index].out_size_v, out_width, out_height);
       set_param_1f(prg[active_index].frame_cnt_v, (float)frame_count);
+      set_param_1f(prg[active_index].frame_dir_v, g_extern.frame_is_reverse ? -1.0 : 1.0);
 
       // Set orig texture.
       CGparameter param = prg[active_index].orig.tex;
@@ -935,10 +939,12 @@ bool gl_cg_init(const char *path)
       prg[i].tex_size_f = cgGetNamedParameter(prg[i].fprg, "IN.texture_size");
       prg[i].out_size_f = cgGetNamedParameter(prg[i].fprg, "IN.output_size");
       prg[i].frame_cnt_f = cgGetNamedParameter(prg[i].fprg, "IN.frame_count");
+      prg[i].frame_dir_f = cgGetNamedParameter(prg[i].fprg, "IN.frame_direction");
       prg[i].vid_size_v = cgGetNamedParameter(prg[i].vprg, "IN.video_size");
       prg[i].tex_size_v = cgGetNamedParameter(prg[i].vprg, "IN.texture_size");
       prg[i].out_size_v = cgGetNamedParameter(prg[i].vprg, "IN.output_size");
       prg[i].frame_cnt_v = cgGetNamedParameter(prg[i].vprg, "IN.frame_count");
+      prg[i].frame_dir_v = cgGetNamedParameter(prg[i].vprg, "IN.frame_direction");
       prg[i].mvp = cgGetNamedParameter(prg[i].vprg, "modelViewProj");
       if (prg[i].mvp)
          cgGLSetStateMatrixParameter(prg[i].mvp, CG_GL_MODELVIEW_PROJECTION_MATRIX, CG_GL_MATRIX_IDENTITY);
diff --git a/gfx/shader_glsl.c b/gfx/shader_glsl.c
index 8aee3bf4ac..bb36b9b2a7 100644
--- a/gfx/shader_glsl.c
+++ b/gfx/shader_glsl.c
@@ -1035,6 +1035,9 @@ void gl_glsl_set_params(unsigned width, unsigned height,
       location = pglGetUniformLocation(gl_program[active_index], "rubyFrameCount");
       pglUniform1i(location, frame_count);
 
+      location = pglGetUniformLocation(gl_program[active_index], "rubyFrameDirection");
+      pglUniform1i(location, g_extern.frame_is_reverse ? -1 : 1);
+
       for (unsigned i = 0; i < gl_teximage_cnt; i++)
       {
          location = pglGetUniformLocation(gl_program[active_index], gl_teximage_uniforms[i]);