From a020e535cac36d69a8939fb7956260d2217c65b4 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Wed, 15 Jun 2016 13:22:00 -0700
Subject: [core] Add a few conveniences to Color

---
 include/mbgl/annotation/annotation.hpp |  4 ++--
 include/mbgl/gl/gl_values.hpp          |  7 ++-----
 include/mbgl/util/color.hpp            | 18 +++++++++++++++---
 3 files changed, 19 insertions(+), 10 deletions(-)

(limited to 'include')

diff --git a/include/mbgl/annotation/annotation.hpp b/include/mbgl/annotation/annotation.hpp
index fc0595af0f..e8ac9a2fb7 100644
--- a/include/mbgl/annotation/annotation.hpp
+++ b/include/mbgl/annotation/annotation.hpp
@@ -30,14 +30,14 @@ public:
     ShapeAnnotationGeometry geometry;
     float opacity = 1;
     float width = 1;
-    Color color = { 0, 0, 0, 1 };
+    Color color = Color::black();
 };
 
 class FillAnnotation {
 public:
     ShapeAnnotationGeometry geometry;
     float opacity = 1;
-    Color color = { 0, 0, 0, 1 };
+    Color color = Color::black();
     Color outlineColor = { 0, 0, 0, -1 };
 };
 
diff --git a/include/mbgl/gl/gl_values.hpp b/include/mbgl/gl/gl_values.hpp
index 4204ca8e13..0d7d294cf7 100644
--- a/include/mbgl/gl/gl_values.hpp
+++ b/include/mbgl/gl/gl_values.hpp
@@ -5,6 +5,7 @@
 #include <array>
 
 #include <mbgl/gl/gl.hpp>
+#include <mbgl/util/color.hpp>
 
 namespace mbgl {
 namespace gl {
@@ -23,7 +24,7 @@ struct ClearDepth {
 };
 
 struct ClearColor {
-    struct Type { GLfloat r, g, b, a; };
+    using Type = Color;
     static const Type Default;
     inline static void Set(const Type& value) {
         MBGL_CHECK_ERROR(glClearColor(value.r, value.g, value.b, value.a));
@@ -35,10 +36,6 @@ struct ClearColor {
     }
 };
 
-inline bool operator!=(const ClearColor::Type& a, const ClearColor::Type& b) {
-    return a.r != b.r || a.g != b.g || a.b != b.b || a.a != b.a;
-}
-
 struct ClearStencil {
     using Type = GLint;
     static const Type Default;
diff --git a/include/mbgl/util/color.hpp b/include/mbgl/util/color.hpp
index 82cd3c42e7..87d3175178 100644
--- a/include/mbgl/util/color.hpp
+++ b/include/mbgl/util/color.hpp
@@ -11,14 +11,26 @@ public:
     float g = 0.0f;
     float b = 0.0f;
     float a = 0.0f;
+
+    static constexpr Color black() { return { 0.0f, 0.0f, 0.0f, 1.0f }; };
+    static constexpr Color white() { return { 1.0f, 1.0f, 1.0f, 1.0f }; };
 };
 
-inline bool operator== (const Color& colorA, const Color& colorB) {
+inline bool operator==(const Color& colorA, const Color& colorB) {
     return colorA.r == colorB.r && colorA.g == colorB.g && colorA.b == colorB.b && colorA.a == colorB.a;
 }
 
-inline bool operator!= (const Color& colorA, const Color& colorB) {
-    return !(colorA.r == colorB.r && colorA.g == colorB.g && colorA.b == colorB.b && colorA.a == colorB.a);
+inline bool operator!=(const Color& colorA, const Color& colorB) {
+    return !(colorA == colorB);
+}
+
+inline Color operator*(const Color& color, float alpha) {
+    return {
+        color.r * alpha,
+        color.g * alpha,
+        color.b * alpha,
+        color.a * alpha
+    };
 }
 
 } // namespace mbgl
-- 
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