From 127e517568490fc147211d8b2fb4da01cecbbeb5 Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Thu, 31 Mar 2016 19:50:28 +1100
Subject: [PATCH 5/6] glcolorconvert: implement multiple render targets for
 GLES3

There are numerous slight differences required between Desktop GL and GLES3 for
multiple render targets.

1. gl_FragData doesn't exist at all and one is required to use
   'layout (location = ?) out ...' instead.
2. gl_FragColor doesn't exist, same as 1
3. texture2D() has been deprecated

Fortunately most of these have been taken care of with GL3 and the shader
mangling already exists so just expand the conditions they are used in.  The
gl_FragData issue requires a new mangle pass though.  We also use this new
pass on desktop GL for consistency.

Upstream-Status: Backport [1.9.1]

---
 gst-libs/gst/gl/gstglcolorconvert.c | 125 ++++++++++++++++++++++++++++--------
 1 file changed, 99 insertions(+), 26 deletions(-)

diff --git a/gst-libs/gst/gl/gstglcolorconvert.c b/gst-libs/gst/gl/gstglcolorconvert.c
index 490ec54..f478faa 100644
--- a/gst-libs/gst/gl/gstglcolorconvert.c
+++ b/gst-libs/gst/gl/gstglcolorconvert.c
@@ -1802,10 +1802,11 @@ _mangle_sampler_type (const gchar * str, GstGLTextureTarget from,
 
 static gchar *
 _mangle_varying_attribute (const gchar * str, guint shader_type,
-    GstGLAPI gl_api)
+    GstGLAPI gl_api, guint gl_major, guint gl_minor)
 {
-  if (gl_api & GST_GL_API_OPENGL3) {
-    if (shader_type == GL_VERTEX_SHADER) {
+  if (shader_type == GL_VERTEX_SHADER) {
+    if ((gl_api & GST_GL_API_OPENGL3) || (gl_api & GST_GL_API_GLES2
+            && gl_major >= 3)) {
       gchar *tmp, *tmp2;
       GRegex *regex;
 
@@ -1821,7 +1822,10 @@ _mangle_varying_attribute (const gchar * str, guint shader_type,
 
       g_free (tmp);
       return tmp2;
-    } else if (shader_type == GL_FRAGMENT_SHADER) {
+    }
+  } else if (shader_type == GL_FRAGMENT_SHADER) {
+    if ((gl_api & GST_GL_API_OPENGL3) || (gl_api & GST_GL_API_GLES2
+            && gl_major > 3)) {
       gchar *tmp;
       GRegex *regex;
 
@@ -1837,28 +1841,48 @@ _mangle_varying_attribute (const gchar * str, guint shader_type,
 }
 
 static gchar *
-_mangle_frag_color (const gchar * str)
+_mangle_frag_color_data (const gchar * str)
 {
   GRegex *regex;
-  gchar *ret;
+  gchar *ret, *tmp;
 
   regex = g_regex_new ("gl_FragColor", 0, 0, NULL);
   ret = g_regex_replace_literal (regex, str, -1, 0, "fragColor", 0, NULL);
   g_regex_unref (regex);
 
+  tmp = ret;
+  /* search and replace 'gl_FragData[NUM]' into fragColor_NUM */
+  regex = g_regex_new ("gl_FragData\\[(\\d+)\\]", 0, 0, NULL);
+  ret = g_regex_replace (regex, tmp, -1, 0, "fragColor_\\1", 0, NULL);
+  g_regex_unref (regex);
+  g_free (tmp);
+
   return ret;
 }
 
 static void
-_mangle_version_profile_from_gl_api (GstGLAPI gl_api, GstGLSLVersion * version,
-    GstGLSLProfile * profile)
+_mangle_version_profile_from_gl_api (GstGLAPI gl_api, gint gl_major,
+    gint gl_minor, GstGLSLVersion * version, GstGLSLProfile * profile)
 {
+  *version = GST_GLSL_VERSION_NONE;
+  *profile = GST_GLSL_PROFILE_NONE;
+
   if (gl_api & GST_GL_API_OPENGL3) {
-    *version = GST_GLSL_VERSION_150;
-    *profile = GST_GLSL_PROFILE_NONE;
+    if (gl_major > 3 || gl_minor >= 3) {
+      *version = GST_GLSL_VERSION_330;
+      *profile = GST_GLSL_PROFILE_CORE;
+    } else {
+      *version = GST_GLSL_VERSION_150;
+      *profile = GST_GLSL_PROFILE_NONE;
+    }
   } else if (gl_api & GST_GL_API_GLES2) {
-    *version = GST_GLSL_VERSION_100;
-    *profile = GST_GLSL_PROFILE_ES;
+    if (gl_major >= 3) {
+      *version = GST_GLSL_VERSION_300;
+      *profile = GST_GLSL_PROFILE_ES;
+    } else if (gl_major >= 2) {
+      *version = GST_GLSL_VERSION_100;
+      *profile = GST_GLSL_PROFILE_ES;
+    }
   } else if (gl_api & GST_GL_API_OPENGL) {
     *version = GST_GLSL_VERSION_110;
     *profile = GST_GLSL_PROFILE_COMPATIBILITY;
@@ -1867,22 +1891,28 @@ _mangle_version_profile_from_gl_api (GstGLAPI gl_api, GstGLSLVersion * version,
 
 static gchar *
 _mangle_shader (const gchar * str, guint shader_type, GstGLTextureTarget from,
-    GstGLTextureTarget to, GstGLAPI gl_api, GstGLSLVersion * version,
-    GstGLSLProfile * profile)
+    GstGLTextureTarget to, GstGLAPI gl_api, gint gl_major, gint gl_minor,
+    GstGLSLVersion * version, GstGLSLProfile * profile)
 {
   gchar *tmp, *tmp2;
 
+  _mangle_version_profile_from_gl_api (gl_api, gl_major, gl_minor, version,
+      profile);
   tmp = _mangle_texture_access (str, from, to, gl_api);
   tmp2 = _mangle_sampler_type (tmp, from, to);
   g_free (tmp);
-  tmp = _mangle_varying_attribute (tmp2, shader_type, gl_api);
+  tmp =
+      _mangle_varying_attribute (tmp2, shader_type, gl_api, gl_major, gl_minor);
   g_free (tmp2);
-  if (shader_type == GL_FRAGMENT_SHADER && gl_api & GST_GL_API_OPENGL3) {
-    tmp2 = _mangle_frag_color (tmp);
-    g_free (tmp);
-    tmp = tmp2;
+  if (shader_type == GL_FRAGMENT_SHADER) {
+    if ((*profile == GST_GLSL_PROFILE_ES && *version >= GST_GLSL_VERSION_300)
+        || (*profile == GST_GLSL_PROFILE_CORE
+            && *version >= GST_GLSL_VERSION_150)) {
+      tmp2 = _mangle_frag_color_data (tmp);
+      g_free (tmp);
+      tmp = tmp2;
+    }
   }
-  _mangle_version_profile_from_gl_api (gl_api, version, profile);
   return tmp;
 }
 
@@ -1899,15 +1929,18 @@ _create_shader (GstGLColorConvert * convert)
   const gchar *strings[2];
   GError *error = NULL;
   GstGLAPI gl_api;
+  gint gl_major, gl_minor;
   int i;
 
   gl_api = gst_gl_context_get_gl_api (convert->context);
+  gst_gl_context_get_gl_version (convert->context, &gl_major, &gl_minor);
 
   ret = gst_gl_shader_new (convert->context);
 
   tmp =
       _mangle_shader (text_vertex_shader, GL_VERTEX_SHADER, info->templ->target,
-      convert->priv->from_texture_target, gl_api, &version, &profile);
+      convert->priv->from_texture_target, gl_api, gl_major, gl_minor, &version,
+      &profile);
 
   tmp1 = gst_glsl_version_profile_to_string (version, profile);
   version_str = g_strdup_printf ("#version %s\n", tmp1);
@@ -1945,9 +1978,37 @@ _create_shader (GstGLColorConvert * convert)
   if (info->templ->uniforms)
     g_string_append (str, info->templ->uniforms);
 
-  if (gl_api & GST_GL_API_OPENGL3) {
-    g_string_append_c (str, '\n');
-    g_string_append (str, "out vec4 fragColor;\n");
+  g_string_append_c (str, '\n');
+
+  /* GL 3.3+ and GL ES 3.x */
+  if ((profile == GST_GLSL_PROFILE_CORE && version >= GST_GLSL_VERSION_330)
+      || (profile == GST_GLSL_PROFILE_ES && version >= GST_GLSL_VERSION_300)) {
+    if (info->out_n_textures > 1) {
+      gint i;
+
+      for (i = 0; i < info->out_n_textures; i++) {
+        g_string_append_printf (str,
+            "layout(location = %d) out vec4 fragColor_%d;\n", i, i);
+      }
+    } else {
+      g_string_append (str, "layout (location = 0) out vec4 fragColor;\n");
+    }
+  } else if (profile == GST_GLSL_PROFILE_CORE
+      && version >= GST_GLSL_VERSION_150) {
+    /* no layout specifiers, use glBindFragDataLocation instead */
+    if (info->out_n_textures > 1) {
+      gint i;
+
+      for (i = 0; i < info->out_n_textures; i++) {
+        gchar *var_name = g_strdup_printf ("fragColor_%d", i);
+        g_string_append_printf (str, "out vec4 %s;\n", var_name);
+        gst_gl_shader_bind_frag_data_location (ret, i, var_name);
+        g_free (var_name);
+      }
+    } else {
+      g_string_append (str, "out vec4 fragColor;\n");
+      gst_gl_shader_bind_frag_data_location (ret, 0, "fragColor");
+    }
   }
 
   for (i = 0; i < MAX_FUNCTIONS; i++) {
@@ -1959,7 +2020,19 @@ _create_shader (GstGLColorConvert * convert)
     g_string_append_c (str, '\n');
   }
 
-  g_string_append (str, "\nvarying vec2 v_texcoord;\nvoid main (void) {\n");
+  {
+    const gchar *varying = NULL;
+
+    if ((profile == GST_GLSL_PROFILE_ES && version >= GST_GLSL_VERSION_300)
+        || (profile == GST_GLSL_PROFILE_CORE
+            && version >= GST_GLSL_VERSION_150)) {
+      varying = "in";
+    } else {
+      varying = "varying";
+    }
+    g_string_append_printf (str, "\n%s vec2 v_texcoord;\nvoid main (void) {\n",
+        varying);
+  }
   if (info->frag_body) {
     g_string_append (str, "vec2 texcoord;\n");
     if (convert->priv->from_texture_target == GST_GL_TEXTURE_TARGET_RECTANGLE
@@ -1975,7 +2048,7 @@ _create_shader (GstGLColorConvert * convert)
   tmp = g_string_free (str, FALSE);
   info->frag_prog = _mangle_shader (tmp, GL_FRAGMENT_SHADER,
       info->templ->target, convert->priv->from_texture_target, gl_api,
-      &version, &profile);
+      gl_major, gl_minor, &version, &profile);
   g_free (tmp);
 
   strings[1] = info->frag_prog;
-- 
1.9.1