libgltf: Append shader language version to the shader files

In general glTF shader files does not contain version
directives and in some case it make shader compiler
using GLSL 1.1 which leads to that the shader compiler
fails.
So we need to append the choosen version number which is
GLSL 1.3 in case of libgltf, but this also means that
from that point OpenGL 3.0 is the new reuirements since
GLSL 1.3 is available only from that version.

Change-Id: Ic4382266432ea474aeb3e603b32a998b9aeed280

2 files changed, 31 insertions, 0 deletions

diff --git a/external/libgltf/UnpackedTarball_libgltf.mk b/external/libgltf/UnpackedTarball_libgltf.mk
index 861eb2e576f6..34214a2b5a4c 100644
--- a/external/libgltf/UnpackedTarball_libgltf.mk
+++ b/external/libgltf/UnpackedTarball_libgltf.mk
@@ -17,6 +17,7 @@ $(eval $(call gb_UnpackedTarball_set_patchlevel,libgltf,1))
 
 $(eval $(call gb_UnpackedTarball_add_patches,libgltf,\
 	external/libgltf/patches/missing_include.patch \
+	external/libgltf/patches/append_shader_version.patch \
 ))
 
 # vim: set noet sw=4 ts=4:
diff --git a/external/libgltf/patches/append_shader_version.patch b/external/libgltf/patches/append_shader_version.patch
new file mode 100644
index 000000000000..dd79515946cf
--- /dev/null
+++ b/external/libgltf/patches/append_shader_version.patch
@@ -0,0 +1,30 @@
+diff -ur libgltf.org/src/Shaders.cpp libgltf/src/Shaders.cpp
+--- libgltf.org/src/Shaders.cpp	2014-08-17 09:15:17.379255115 +0200
++++ libgltf/src/Shaders.cpp	2014-08-17 09:16:43.323258781 +0200
+@@ -11,6 +11,7 @@
+ 
+ #include <GL/glew.h>
+ #include <cstdio>
++#include <cstring>
+ 
+ namespace libgltf
+ {
+@@ -166,7 +167,17 @@
+                                   unsigned int shaderId)
+ {
+     GLint iGLSize = iSize;
+-    glShaderSource(shaderId, 1, &pShader, &iGLSize);
++    const GLchar* aSources[] = {
++        "#version 130\n",
++        pShader,
++    };
++
++    const GLint aSizes[] = {
++        strlen("#version 130\n"),
++        iGLSize,
++    };
++
++    glShaderSource(shaderId, 2, &aSources[0], &aSizes[0]);
+     glCompileShader(shaderId);
+     int iStatus = 0;
+     glGetShaderiv(shaderId, GL_COMPILE_STATUS, &iStatus);