From aaa8fc1f37ce2bd32edfcacd1d236d0d01905920 Mon Sep 17 00:00:00 2001
From: twinaphex <libretro@gmail.com>
Date: Tue, 29 Oct 2013 23:21:15 +0100
Subject: [PATCH] (GLES2 GL) Query GL_EXT_unpack_subimage and if it's there,
 use it - Tegra 4 should support it etc.

---
 gfx/gl.c        | 18 ++++++++++++++++++
 gfx/gl_common.h | 11 +++++++++--
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/gfx/gl.c b/gfx/gl.c
index 7c1e4d173d..ed10fb6b90 100644
--- a/gfx/gl.c
+++ b/gfx/gl.c
@@ -1234,6 +1234,15 @@ static inline void gl_copy_frame(void *data, const void *frame, unsigned width,
                0, 0, 0, width, height, gl->texture_type,
                gl->texture_fmt, gl->conv_buffer);
       }
+      else if (gl->support_unpack_row_length)
+      {
+         glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch / gl->base_size);
+         glTexSubImage2D(GL_TEXTURE_2D,
+               0, 0, 0, width, height, gl->texture_type,
+               gl->texture_fmt, frame);
+
+         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+      }
       else
       {
          // No GL_UNPACK_ROW_LENGTH ;(
@@ -2152,6 +2161,15 @@ static void *gl_init(const video_info_t *video, const input_driver_t **input, vo
    gl_init_pbo_readback(gl);
 #endif
 
+#if defined(HAVE_OPENGLES)
+   gl->support_unpack_row_length = false;
+   if (gl_query_extension(gl, "GL_EXT_unpack_subimage"))
+   {
+      RARCH_LOG("[GL]: Extension GL_EXT_unpack_subimage, can copy textures faster using UNPACK_ROW_LENGTH.\n");
+      gl->support_unpack_row_length = true;
+   }
+#endif
+
    if (!gl_check_error())
    {
       context_destroy_func();
diff --git a/gfx/gl_common.h b/gfx/gl_common.h
index d864a3c464..e722d4bee6 100644
--- a/gfx/gl_common.h
+++ b/gfx/gl_common.h
@@ -209,6 +209,9 @@ typedef struct gl
    GLenum texture_fmt;
    GLenum wrap_mode;
    unsigned base_size; // 2 or 4
+#ifdef HAVE_OPENGLES
+   bool support_unpack_row_length;
+#endif
 
    // Fonts
    void *font;
@@ -309,8 +312,12 @@ typedef struct gl
 #define NO_GL_CLAMP_TO_BORDER
 #endif
 
-#if defined(HAVE_OPENGLES2) // It's an extension. Don't bother checking for it atm.
-#undef GL_UNPACK_ROW_LENGTH
+#if defined(HAVE_OPENGLES)
+
+#ifndef GL_UNPACK_ROW_LENGTH
+#define GL_UNPACK_ROW_LENGTH  0x0CF2
+#endif
+
 #endif
 
 void gl_set_projection(void *data, struct gl_ortho *ortho, bool allow_rotate);