Work around certain buggy Vivante GPU drivers on Android

love2d/love-android#204

src/modules/graphics/opengl/OpenGL.cpp

@@ -124,6 +124,20 @@ bool OpenGL::initContext()
 	if (!gladLoadGLLoader(LOVEGetProcAddress))
 		return false;
 
+	initVendor();
+
+	bugs = {};
+
+	if (GLAD_ES_VERSION_3_0 && !GLAD_ES_VERSION_3_1)
+	{
+		const char *device = (const char *) glGetString(GL_RENDERER);
+		if (getVendor() == VENDOR_VIVANTE && strstr(device, "Vivante GC7000UL"))
+			bugs.brokenGLES3 = true;
+	}
+
+	if (bugs.brokenGLES3)
+		GLAD_ES_VERSION_3_0 = false;
+
 	if (GLAD_VERSION_3_2)
 	{
 		GLint profileMask = 0;
@@ -134,9 +148,6 @@ bool OpenGL::initContext()
 		coreProfile = false;
 
 	initOpenGLFunctions();
-	initVendor();
-
-	bugs = {};
 
 #if defined(LOVE_WINDOWS) || defined(LOVE_LINUX)
 	// See the comments in OpenGL.h.

src/modules/graphics/opengl/OpenGL.h

@@ -184,6 +184,13 @@ public:
 		 **/
 		bool brokenSRGB;
 
+		/**
+		 * Some Android graphics drivers claim to support GLES3.0 but have bugs
+		 * with certain aspects that users expect to work. For example:
+		 * https://github.com/love2d/love-android/issues/204
+		 **/
+		bool brokenGLES3;
+
 		/**
 		 * Other bugs which have workarounds that don't use conditional code at
 		 * the moment:

src/modules/graphics/wrap_GraphicsShader.lua

@@ -95,7 +95,7 @@ GLSL.FUNCTIONS = [[
 	#if __VERSION__ >= 300 || defined(GL_OES_texture_3D)
 		precision lowp sampler3D;
 	#endif
-	#if __VERSION__ >= 300
+	#if __VERSION__ >= 300 && !defined(LOVE_GLSL1_ON_GLSL3)
 		precision lowp sampler2DShadow;
 		precision lowp samplerCubeShadow;
 		precision lowp sampler2DArrayShadow;