Index: binaries/data/mods/public/shaders/glsl/model_common.fs
===================================================================
--- binaries/data/mods/public/shaders/glsl/model_common.fs
+++ binaries/data/mods/public/shaders/glsl/model_common.fs
@@ -129,13 +129,13 @@
     float height = 1.0;
     float scale = effectSettings.z;
 	  
-    int iter = int(min(20, 25.0 - dist/10.0));
+    int iter = int(min(20.0, 25.0 - dist/10.0));
 	
-	if (iter > 0.01)
+	if (iter > 0)
 	{
-		float s = 1.0/iter;
+		float s = 1.0/float(iter);
 		float t = s;
-		move = vec2(-eyeDir.x, eyeDir.y) * scale / (eyeDir.z * iter);
+		move = vec2(-eyeDir.x, eyeDir.y) * scale / (eyeDir.z * float(iter));
 		vec2 nil = vec2(0.0);
 
 		for (int i = 0; i < iter; ++i) {
Index: source/gui/ObjectTypes/CChart.cpp
===================================================================
--- source/gui/ObjectTypes/CChart.cpp
+++ source/gui/ObjectTypes/CChart.cpp
@@ -86,12 +86,16 @@
 	shader->VertexPointer(3, GL_FLOAT, 0, &vertices[0]);
 	shader->AssertPointersBound();
 
+#if !CONFIG2_GLES
 	glEnable(GL_LINE_SMOOTH);
+#endif
 	glLineWidth(1.1f);
 	if (!g_Renderer.m_SkipSubmit)
 		glDrawArrays(GL_LINE_STRIP, 0, vertices.size() / 3);
 	glLineWidth(1.0f);
+#if !CONFIG2_GLES
 	glDisable(GL_LINE_SMOOTH);
+#endif
 }
 
 void CChart::DrawTriangleStrip(const CShaderProgramPtr& shader, const CGUIColor& color, const std::vector<float>& vertices) const
Index: source/lib/external_libraries/glext_funcs.h
===================================================================
--- source/lib/external_libraries/glext_funcs.h
+++ source/lib/external_libraries/glext_funcs.h
@@ -65,8 +65,6 @@
 
 #if CONFIG2_GLES
 
-// no GLES extensions used yet
-
 // some functions that are extensions in GL are core functions in GLES,
 // so we should use them without the function pointer indirection
 #define pglActiveTextureARB glActiveTexture
@@ -106,22 +104,41 @@
 #define pglBufferSubDataARB glBufferSubData
 #define pglDeleteBuffersARB glDeleteBuffers
 #define pglGenBuffersARB glGenBuffers
-#define pglMapBufferARB glMapBuffer
-#define pglUnmapBufferARB glUnmapBuffer
 
+// Those EXT symbols don’t exist in GLES 2.0, since it imported the ARB version instead.
 #define pglBindFramebufferEXT glBindFramebuffer
 #define pglCheckFramebufferStatusEXT glCheckFramebufferStatus
 #define pglDeleteFramebuffersEXT glDeleteFramebuffers
 #define pglFramebufferTexture2DEXT glFramebufferTexture2D
 #define pglGenFramebuffersEXT glGenFramebuffers
-
-#define GL_DEPTH_ATTACHMENT_EXT GL_DEPTH_ATTACHMENT
-#define GL_COLOR_ATTACHMENT0_EXT GL_COLOR_ATTACHMENT0
 #define GL_FRAMEBUFFER_BINDING_EXT GL_FRAMEBUFFER_BINDING
 #define GL_FRAMEBUFFER_COMPLETE_EXT GL_FRAMEBUFFER_COMPLETE
 #define GL_FRAMEBUFFER_EXT GL_FRAMEBUFFER
 
-#define GL_CLAMP_TO_BORDER GL_CLAMP_TO_EDGE // TODO: should fix code that relies on GL_CLAMP_TO_BORDER
+// Those should come from GLES 2.0 core, not from GL_EXT_draw_buffers.
+#ifndef GL_COLOR_ATTACHMENT0_EXT
+#define GL_COLOR_ATTACHMENT0_EXT GL_COLOR_ATTACHMENT0
+#define GL_COLOR_ATTACHMENT1_EXT GL_COLOR_ATTACHMENT1
+#endif
+#ifndef GL_DEPTH_ATTACHMENT_EXT
+#define GL_DEPTH_ATTACHMENT_EXT GL_DEPTH_ATTACHMENT
+#endif
+
+// GL_OES_mapbuffer
+FUNC(void*, glMapBufferOES, (int target, int access))
+FUNC(bool, glUnmapBufferOES, (int target))
+#define pglMapBufferARB pglMapBufferOES
+#define pglUnmapBufferARB pglUnmapBufferOES
+#define GL_WRITE_ONLY GL_WRITE_ONLY_OES
+
+// GL_OES_texture_border_clamp
+#define GL_CLAMP_TO_BORDER GL_CLAMP_TO_EDGE
+
+// GL_OES_rgb8_rgba8
+#define GL_RGBA8 GL_RGBA8_OES
+
+// GL_OES_depth32
+#define GL_DEPTH_COMPONENT32 GL_DEPTH_COMPONENT32_OES
 
 typedef GLuint GLhandleARB;
 
Index: source/ps/GameSetup/Config.cpp
===================================================================
--- source/ps/GameSetup/Config.cpp
+++ source/ps/GameSetup/Config.cpp
@@ -52,7 +52,7 @@
 bool g_Silhouettes = false;
 bool g_ShowSky = false;
 
-bool g_PreferGLSL = false;
+bool g_PreferGLSL = true;
 bool g_PostProc = false;
 bool g_SmoothLOS = false;
 
@@ -106,7 +106,9 @@
 	CFG_GET_VAL("fog", g_Fog);
 	CFG_GET_VAL("silhouettes", g_Silhouettes);
 	CFG_GET_VAL("showsky", g_ShowSky);
+#if !CONFIG2_GLES
 	CFG_GET_VAL("preferglsl", g_PreferGLSL);
+#endif
 	CFG_GET_VAL("postproc", g_PostProc);
 	CFG_GET_VAL("smoothlos", g_SmoothLOS);
 	CFG_GET_VAL("gui.scale", g_GuiScale);
Index: source/ps/GameSetup/HWDetect.cpp
===================================================================
--- source/ps/GameSetup/HWDetect.cpp
+++ source/ps/GameSetup/HWDetect.cpp
@@ -712,7 +712,9 @@
 #endif // CONFIG2_GLES
 
 
-#ifdef SDL_VIDEO_DRIVER_X11
+// TODO: Running on X11 doesn’t imply that we use GLX, EGL is a totally valid
+// API on this platform too.
+#if defined(SDL_VIDEO_DRIVER_X11) && !CONFIG2_GLES
 
 #define GLXQCR_INTEGER(id) do { \
 	unsigned int i = UINT_MAX; \
Index: source/renderer/Renderer.cpp
===================================================================
--- source/renderer/Renderer.cpp
+++ source/renderer/Renderer.cpp
@@ -433,11 +433,6 @@
 	if (skycolor.ParseString(skystring, 255.f))
 		SetClearColor(skycolor.AsSColor4ub());
 
-#if CONFIG2_GLES
-	// Override config option since GLES only supports GLSL
-	g_RenderingOptions.GetPreferGLSL() = true;
-#endif
-
 	m_ShadowZBias = 0.02f;
 	m_ShadowMapSize = 0;
 
Index: source/renderer/SkyManager.cpp
===================================================================
--- source/renderer/SkyManager.cpp
+++ source/renderer/SkyManager.cpp
@@ -126,11 +126,11 @@
 				}
 			}
 
-			glTexImage2D(types[i], 0, GL_RGB, tex.m_Width, tex.m_Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &rotated[0]);
+			glTexImage2D(types[i], 0, GL_RGBA, tex.m_Width, tex.m_Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &rotated[0]);
 		}
 		else
 		{
-			glTexImage2D(types[i], 0, GL_RGB, tex.m_Width, tex.m_Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
+			glTexImage2D(types[i], 0, GL_RGBA, tex.m_Width, tex.m_Height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
 		}
 	}