From 084294e60b516656a2bb8b6157c59806abf8867f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Vladim=C3=ADr=20Vondru=C5=A1?= <mosra@centrum.cz>
Date: Sun, 4 Nov 2012 16:09:09 +0100
Subject: [PATCH] Blind port of PhongShader to OpenGL ES 2.0.

---
 src/Shaders/CMakeLists.txt     |  3 ++-
 src/Shaders/PhongShader.cpp    | 23 ++++++++++++++++++++---
 src/Shaders/PhongShader.frag   |  4 ++--
 src/Shaders/PhongShader.vert   |  5 ++---
 src/Shaders/compatibility.glsl | 14 ++++++++++++++
 5 files changed, 40 insertions(+), 9 deletions(-)
 create mode 100644 src/Shaders/compatibility.glsl

diff --git a/src/Shaders/CMakeLists.txt b/src/Shaders/CMakeLists.txt
index 53b99a0f2..926bc6238 100644
--- a/src/Shaders/CMakeLists.txt
+++ b/src/Shaders/CMakeLists.txt
@@ -1,6 +1,7 @@
 corrade_add_resource(MagnumShaders_RCS MagnumShaders
     FlatShader2D.vert FlatShader2D.frag
-    PhongShader.frag PhongShader.vert)
+    PhongShader.frag PhongShader.vert
+    compatibility.glsl)
 set(MagnumShaders_SRCS
     FlatShader.cpp
     PhongShader.cpp
diff --git a/src/Shaders/PhongShader.cpp b/src/Shaders/PhongShader.cpp
index 8d79c69ba..394243dcb 100644
--- a/src/Shaders/PhongShader.cpp
+++ b/src/Shaders/PhongShader.cpp
@@ -24,11 +24,28 @@ namespace Magnum { namespace Shaders {
 
 PhongShader::PhongShader() {
     Corrade::Utility::Resource rs("MagnumShaders");
-    Version v = Context::current()->isVersionSupported(Version::GL320) ? Version::GL320 : Version::GL210;
-    attachShader(Shader::fromData(v, Shader::Type::Vertex, rs.get("PhongShader.vert")));
-    attachShader(Shader::fromData(v, Shader::Type::Fragment, rs.get("PhongShader.frag")));
 
+    #ifndef MAGNUM_TARGET_GLES
+    Version v = Context::current()->supportedVersion({Version::GL320, Version::GL210});
+    #else
+    Version v = Context::current()->supportedVersion({Version::GLES300, Version::GLES200});
+    #endif
+
+    Shader vertexShader(v, Shader::Type::Vertex);
+    vertexShader.addSource(rs.get("compatibility.glsl"));
+    vertexShader.addSource(rs.get("PhongShader.vert"));
+    attachShader(vertexShader);
+
+    Shader fragmentShader(v, Shader::Type::Fragment);
+    fragmentShader.addSource(rs.get("compatibility.glsl"));
+    fragmentShader.addSource(rs.get("PhongShader.frag"));
+    attachShader(fragmentShader);
+
+    #ifndef MAGNUM_TARGET_GLES
     if(!Context::current()->isExtensionSupported<Extensions::GL::ARB::explicit_attrib_location>()) {
+    #else
+    if(!Context::current()->isVersionSupported(Version::GLES300)) {
+    #endif
         bindAttributeLocation(Position::Location, "position");
         bindAttributeLocation(Normal::Location, "normal");
     }
diff --git a/src/Shaders/PhongShader.frag b/src/Shaders/PhongShader.frag
index c6d9c9be5..638a1e3fa 100644
--- a/src/Shaders/PhongShader.frag
+++ b/src/Shaders/PhongShader.frag
@@ -1,4 +1,4 @@
-#if __VERSION__ == 120
+#ifndef NEW_GLSL
 #define in varying
 #define color gl_FragColor
 #endif
@@ -13,7 +13,7 @@ in vec3 transformedNormal;
 in vec3 lightDirection;
 in vec3 cameraDirection;
 
-#if __VERSION__ != 120
+#ifdef NEW_GLSL
 out vec4 color;
 #endif
 
diff --git a/src/Shaders/PhongShader.vert b/src/Shaders/PhongShader.vert
index 3872fcc74..1c794cbce 100644
--- a/src/Shaders/PhongShader.vert
+++ b/src/Shaders/PhongShader.vert
@@ -1,4 +1,4 @@
-#if __VERSION__ == 120
+#ifndef NEW_GLSL
 #define in attribute
 #define out varying
 #endif
@@ -7,8 +7,7 @@ uniform mat4 transformationMatrix;
 uniform mat4 projectionMatrix;
 uniform vec3 light;
 
-#if __VERSION__ != 120 && defined(GL_ARB_explicit_attrib_location)
-#extension GL_ARB_explicit_attrib_location: enable
+#ifdef EXPLICIT_ATTRIB_LOCATION
 layout(location = 0) in vec4 position;
 layout(location = 1) in vec3 normal;
 #else
diff --git a/src/Shaders/compatibility.glsl b/src/Shaders/compatibility.glsl
new file mode 100644
index 000000000..2ccbfae6b
--- /dev/null
+++ b/src/Shaders/compatibility.glsl
@@ -0,0 +1,14 @@
+#if (!defined(GL_ES) && __VERSION__ >= 130) || (defined(GL_ES) && __VERSION__ >= 300)
+#define NEW_GLSL
+#endif
+
+/* On NVidia and GLSL 1.20 layout qualifiers result in parsing error, even if
+   the extension is defined as supported */
+#if !defined(GL_ES) && __VERSION__ >= 120 && defined(GL_ARB_explicit_attrib_location)
+#extension GL_ARB_explicit_attrib_location: enable
+#define EXPLICIT_ATTRIB_LOCATION
+#endif
+
+#if defined(GL_ES) && __VERSION__ >= 300
+#define EXPLICIT_ATTRIB_LOCATION
+#endif