Implement GL_EXT_blend_minmax support

src/GLES2/libGLESv2/Context.cpp

@@ -497,7 +497,6 @@ void Context::setPolygonOffsetFill(bool enabled)
 bool Context::isPolygonOffsetFillEnabled() const
 {
     return mState.polygonOffsetFill;
-
 }
 
 void Context::setPolygonOffsetParams(GLfloat factor, GLfloat units)
@@ -2743,6 +2742,7 @@ void Context::initExtensionString()
 	mExtensionString += "GL_OES_texture_half_float ";
 	mExtensionString += "GL_OES_texture_half_float_linear ";
 	mExtensionString += "GL_OES_texture_npot ";
+	mExtensionString += "GL_EXT_blend_minmax ";
 	mExtensionString += "GL_EXT_occlusion_query_boolean ";
 	mExtensionString += "GL_EXT_read_format_bgra ";
 

src/GLES2/libGLESv2/libGLESv2.cpp

@@ -428,6 +428,8 @@ void GL_APIENTRY glBlendEquationSeparate(GLenum modeRGB, GLenum modeAlpha)
         case GL_FUNC_ADD:
         case GL_FUNC_SUBTRACT:
         case GL_FUNC_REVERSE_SUBTRACT:
+        case GL_MIN_EXT:
+        case GL_MAX_EXT:
             break;
         default:
             return error(GL_INVALID_ENUM);
@@ -438,6 +440,8 @@ void GL_APIENTRY glBlendEquationSeparate(GLenum modeRGB, GLenum modeAlpha)
         case GL_FUNC_ADD:
         case GL_FUNC_SUBTRACT:
         case GL_FUNC_REVERSE_SUBTRACT:
+        case GL_MIN_EXT:
+        case GL_MAX_EXT:
             break;
         default:
             return error(GL_INVALID_ENUM);

src/GLES2/libGLESv2/utilities.cpp

@@ -512,6 +512,8 @@ namespace es2sw
 		case GL_FUNC_ADD:              return sw::Context::BLENDOP_ADD;
 		case GL_FUNC_SUBTRACT:         return sw::Context::BLENDOP_SUB;
 		case GL_FUNC_REVERSE_SUBTRACT: return sw::Context::BLENDOP_INVSUB;
+		case GL_MIN_EXT:               return sw::Context::BLENDOP_MIN;
+		case GL_MAX_EXT:               return sw::Context::BLENDOP_MAX;
 		default: UNREACHABLE();
 		}