Split debayer fragment between packed and unpacked, fixing preview for unpacked 10bit bayer formats

src/gles2_debayer.h

@@ -5,7 +5,8 @@
 #include <stdio.h>
 
 #define SHADER_DEBAYER 1
-#define SHADER_YUV 2
+#define SHADER_DEBAYER_PACKED 2
+#define SHADER_YUV 3
 
 typedef struct {
         int format;
@@ -47,3 +48,6 @@ void gles2_debayer_set_shading(GLES2Debayer *self,
                                float blacklevel);
 
 void gles2_debayer_process(GLES2Debayer *self, GLuint dst_id, GLuint source_id);
+
+const char* gles2_shader_to_fragment(int shader);
+const char* gles2_shader_to_vertex(int shader);