1 files changed, 95 insertions, 0 deletions
diff --git a/src/mbgl/gl/color_mode.hpp b/src/mbgl/gl/color_mode.hpp
new file mode 100644
index 0000000000..e73c8737eb
--- /dev/null
+++ b/src/mbgl/gl/color_mode.hpp
@@ -0,0 +1,95 @@
+#pragma once
+
+#include <mbgl/util/variant.hpp>
+#include <mbgl/util/color.hpp>
+
+namespace mbgl {
+namespace gl {
+
+class ColorMode {
+public:
+    enum class BlendEquation {
+        Add                   = 0x8006,
+        Subtract              = 0x800A,
+        ReverseSubtract       = 0x800B
+    };
+
+    enum BlendFactor {
+        Zero                  = 0x0000,
+        One                   = 0x0001,
+        SrcColor              = 0x0300,
+        OneMinusSrcColor      = 0x0301,
+        SrcAlpha              = 0x0302,
+        OneMinusSrcAlpha      = 0x0303,
+        DstAlpha              = 0x0304,
+        OneMinusDstAlpha      = 0x0305,
+        DstColor              = 0x0306,
+        OneMinusDstColor      = 0x0307,
+        SrcAlphaSaturate      = 0x0308,
+        ConstantColor         = 0x8001,
+        OneMinusConstantColor = 0x8002,
+        ConstantAlpha         = 0x8003,
+        OneMinusConstantAlpha = 0x8004
+    };
+
+    template <BlendEquation E>
+    struct ConstantBlend {
+        static constexpr BlendEquation equation = E;
+        static constexpr BlendFactor srcFactor = One;
+        static constexpr BlendFactor dstFactor = One;
+    };
+
+    template <BlendEquation E>
+    struct LinearBlend {
+        static constexpr BlendEquation equation = E;
+        BlendFactor srcFactor;
+        BlendFactor dstFactor;
+    };
+
+    struct Replace {
+        static constexpr BlendEquation equation = BlendEquation::Add;
+        static constexpr BlendFactor srcFactor = One;
+        static constexpr BlendFactor dstFactor = One;
+    };
+
+    using Add              = LinearBlend<BlendEquation::Add>;
+    using Subtract         = LinearBlend<BlendEquation::Subtract>;
+    using ReverseSubtract  = LinearBlend<BlendEquation::ReverseSubtract>;
+
+    using BlendFunction = variant<
+        Replace,
+        Add,
+        Subtract,
+        ReverseSubtract>;
+
+    BlendFunction blendFunction;
+    Color blendColor;
+
+    struct Mask {
+        bool r;
+        bool g;
+        bool b;
+        bool a;
+    };
+
+    Mask mask;
+
+    static ColorMode disabled() {
+       return ColorMode { Replace(), {}, { false, false, false, false } };
+    }
+
+    static ColorMode unblended() {
+       return ColorMode { Replace(), {}, { true, true, true, true } };
+    }
+
+    static ColorMode alphaBlended() {
+        return ColorMode { Add { One, OneMinusSrcAlpha }, {}, { true, true, true, true } };
+    }
+};
+
+constexpr bool operator!=(const ColorMode::Mask& a, const ColorMode::Mask& b) {
+    return a.r != b.r || a.g != b.g || a.b != b.b || a.a != b.a;
+}
+
+} // namespace gl
+} // namespace mbgl