Use feature detection macros everywhere

examples/SampleUtils.cpp

@@ -12,14 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "common/Platform.h"
 #include "utils/BackendBinding.h"
-#include "../src/wire/TerribleCommandBuffer.h"
+#include "wire/TerribleCommandBuffer.h"
 
 // Include Windows.h before GLFW to avoid a redefinition of APIENTRY
-#ifdef _WIN32
+#if defined(NXT_PLATFORM_WINDOWS)
     #include <Windows.h>
-#else
+#elif defined(NXT_PLATFORM_POSIX)
    #include <unistd.h>
+#else
+    #error "Unsupported platform."
 #endif
 
 #include <nxt/nxt.h>
@@ -176,14 +179,16 @@ void DoSwapBuffers() {
     binding->SwapBuffers();
 }
 
-#ifdef _WIN32
+#if defined(NXT_PLATFORM_WINDOWS)
     void USleep(uint64_t usecs) {
         Sleep(static_cast<DWORD>(usecs / 1000));
     }
-#else
+#elif defined(NXT_PLATFORM_POSIX)
     void USleep(uint64_t usecs) {
         usleep(usecs);
     }
+#else
+    #error "Implement USleep for your platform."
 #endif
 
 bool ShouldQuit() {

src/backend/opengl/ShaderModuleGL.cpp

@@ -49,7 +49,7 @@ namespace opengl {
         spirv_cross::CompilerGLSL::Options options;
 
         // TODO(cwallez@chromium.org): discover the backing context version and use that.
-#if defined(__APPLE__)
+#if defined(NXT_PLATFORM_APPLE)
         options.version = 410;
 #else
         options.version = 450;

src/common/CMakeLists.txt

@@ -21,6 +21,7 @@ list(APPEND COMMON_SOURCES
     ${COMMON_DIR}/Compiler.h
     ${COMMON_DIR}/Math.cpp
     ${COMMON_DIR}/Math.h
+    ${COMMON_DIR}/Platform.h
     ${COMMON_DIR}/Serial.h
     ${COMMON_DIR}/SerialQueue.h
 )

src/common/Math.cpp

@@ -16,13 +16,13 @@
 
 #include "common/Assert.h"
 
-#if defined(_WIN32) || defined(_WIN64)
+#if defined(NXT_COMPILER_MSVC)
     #include <intrin.h>
 #endif
 
 uint32_t ScanForward(uint32_t bits) {
     ASSERT(bits != 0);
-    #if defined(_WIN32) || defined(_WIN64)
+    #if defined(NXT_COMPILER_MSVC)
         unsigned long firstBitIndex = 0ul;
         unsigned char ret = _BitScanForward(&firstBitIndex, bits);
         ASSERT(ret != 0);
@@ -34,7 +34,7 @@ uint32_t ScanForward(uint32_t bits) {
 
 uint32_t Log2(uint32_t value) {
     ASSERT(value != 0);
-    #if defined(_WIN32) || defined(_WIN64)
+    #if defined(NXT_COMPILER_MSVC)
         unsigned long firstBitIndex = 0ul;
         unsigned char ret = _BitScanReverse(&firstBitIndex, value);
         ASSERT(ret != 0);

src/common/Platform.h

@@ -0,0 +1,30 @@
+// Copyright 2017 The NXT Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef COMMON_PLATFORM_H_
+#define COMMON_PLATFORM_H_
+
+#if defined(_WIN32) || defined(_WIN64)
+    #define NXT_PLATFORM_WINDOWS 1
+#elif defined(__linux__)
+    #define NXT_PLATFORM_LINUX 1
+    #define NXT_PLATFORM_POSIX 1
+#elif defined(__APPLE__)
+    #define NXT_PLATFORM_APPLE 1
+    #define NXT_PLATFORM_POSIX 1
+#else
+    #error "Unsupported platform."
+#endif
+
+#endif // COMMON_PLATFORM_H_

src/utils/OpenGLBinding.cpp

@@ -29,7 +29,7 @@ namespace utils {
     class OpenGLBinding : public BackendBinding {
         public:
             void SetupGLFWWindowHints() override {
-                #ifdef __APPLE__
+                #if defined(NXT_PLATFORM_APPLE)
                     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
                     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
                     glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);