[core] move GL value accessors to gl::value namespace

1 files changed, 382 insertions, 0 deletions

diff --git a/src/mbgl/gl/value.hpp b/src/mbgl/gl/value.hpp
new file mode 100644
index 0000000000..6436228ed1
--- /dev/null
+++ b/src/mbgl/gl/value.hpp
@@ -0,0 +1,382 @@
+#pragma once
+
+#include <cstdint>
+#include <tuple>
+#include <array>
+#include <cassert>
+
+#include <mbgl/gl/gl.hpp>
+#include <mbgl/util/color.hpp>
+
+namespace mbgl {
+namespace gl {
+namespace value {
+
+struct ClearDepth {
+    using Type = GLfloat;
+    static const constexpr Type Default = 1;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glClearDepth(value));
+    }
+    static Type Get() {
+        Type clearDepth;
+        MBGL_CHECK_ERROR(glGetFloatv(GL_DEPTH_CLEAR_VALUE, &clearDepth));
+        return clearDepth;
+    }
+};
+
+struct ClearColor {
+    using Type = Color;
+    static const constexpr Type Default = { 0, 0, 0, 0 };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glClearColor(value.r, value.g, value.b, value.a));
+    }
+    static Type Get() {
+        GLfloat floats[4];
+        MBGL_CHECK_ERROR(glGetFloatv(GL_COLOR_CLEAR_VALUE, floats));
+        return { floats[0], floats[1], floats[2], floats[3] };
+    }
+};
+
+struct ClearStencil {
+    using Type = GLint;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glClearStencil(value));
+    }
+    static Type Get() {
+        Type clearStencil;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_CLEAR_VALUE, &clearStencil));
+        return clearStencil;
+    }
+};
+
+struct StencilMask {
+    using Type = GLuint;
+    static const constexpr Type Default = ~0u;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glStencilMask(value));
+    }
+    static Type Get() {
+        GLint stencilMask;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_WRITEMASK, &stencilMask));
+        return stencilMask;
+    }
+};
+
+struct DepthMask {
+    using Type = GLboolean;
+    static const constexpr Type Default = GL_TRUE;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glDepthMask(value));
+    }
+    static Type Get() {
+        Type depthMask;
+        MBGL_CHECK_ERROR(glGetBooleanv(GL_DEPTH_WRITEMASK, &depthMask));
+        return depthMask;
+    }
+};
+
+struct ColorMask {
+    struct Type { bool r, g, b, a; };
+    static const constexpr Type Default = { GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glColorMask(value.r, value.g, value.b, value.a));
+    }
+    static Type Get() {
+        GLboolean bools[4];
+        MBGL_CHECK_ERROR(glGetBooleanv(GL_COLOR_WRITEMASK, bools));
+        return { static_cast<bool>(bools[0]), static_cast<bool>(bools[1]),
+                 static_cast<bool>(bools[2]), static_cast<bool>(bools[3]) };
+    }
+};
+
+constexpr bool operator!=(const ColorMask::Type& a, const ColorMask::Type& b) {
+    return a.r != b.r || a.g != b.g || a.b != b.b || a.a != b.a;
+}
+
+struct StencilFunc {
+    struct Type { GLenum func; GLint ref; GLuint mask; };
+    static const constexpr Type Default = { GL_ALWAYS, 0, ~0u };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glStencilFunc(value.func, value.ref, value.mask));
+    }
+    static Type Get() {
+        GLint func, ref, mask;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_FUNC, &func));
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_REF, &ref));
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_VALUE_MASK, &mask));
+        return { static_cast<GLenum>(func), ref, static_cast<GLuint>(mask) };
+    }
+};
+
+constexpr bool operator!=(const StencilFunc::Type& a, const StencilFunc::Type& b) {
+    return a.func != b.func || a.ref != b.ref || a.mask != b.mask;
+}
+
+struct StencilTest {
+    using Type = bool;
+    static const constexpr Type Default = GL_FALSE;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(value ? glEnable(GL_STENCIL_TEST) : glDisable(GL_STENCIL_TEST));
+    }
+    static Type Get() {
+        Type stencilTest;
+        MBGL_CHECK_ERROR(stencilTest = glIsEnabled(GL_STENCIL_TEST));
+        return stencilTest;
+    }
+};
+
+struct StencilOp {
+    struct Type { GLenum sfail, dpfail, dppass; };
+    static const constexpr Type Default = { GL_KEEP, GL_KEEP, GL_REPLACE };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glStencilOp(value.sfail, value.dpfail, value.dppass));
+    }
+    static Type Get() {
+        GLint sfail, dpfail, dppass;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_FAIL, &sfail));
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_PASS_DEPTH_FAIL, &dpfail));
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_STENCIL_PASS_DEPTH_PASS, &dppass));
+        return { static_cast<GLenum>(sfail), static_cast<GLenum>(dpfail), static_cast<GLuint>(dppass) };
+    }
+};
+
+constexpr bool operator!=(const StencilOp::Type& a, const StencilOp::Type& b) {
+    return a.sfail != b.sfail || a.dpfail != b.dpfail || a.dppass != b.dppass;
+}
+
+struct DepthRange {
+    struct Type { GLfloat near, far; };
+    static const constexpr Type Default = { 0, 1 };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glDepthRange(value.near, value.far));
+    }
+    static Type Get() {
+        GLfloat floats[2];
+        MBGL_CHECK_ERROR(glGetFloatv(GL_DEPTH_RANGE, floats));
+        return { floats[0], floats[1] };
+    }
+};
+
+constexpr bool operator!=(const DepthRange::Type& a, const DepthRange::Type& b) {
+    return a.near != b.near || a.far != b.far;
+}
+
+struct DepthTest {
+    using Type = bool;
+    static const constexpr Type Default = GL_FALSE;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(value ? glEnable(GL_DEPTH_TEST) : glDisable(GL_DEPTH_TEST));
+    }
+    static Type Get() {
+        Type depthTest;
+        MBGL_CHECK_ERROR(depthTest = glIsEnabled(GL_DEPTH_TEST));
+        return depthTest;
+    }
+};
+
+struct DepthFunc {
+    using Type = GLenum;
+    static const constexpr Type Default = GL_LEQUAL;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glDepthFunc(value));
+    }
+    static Type Get() {
+        GLint depthFunc;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_DEPTH_FUNC, &depthFunc));
+        return depthFunc;
+    }
+};
+
+struct Blend {
+    using Type = bool;
+    static const constexpr Type Default = GL_TRUE;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(value ? glEnable(GL_BLEND) : glDisable(GL_BLEND));
+    }
+    static Type Get() {
+        Type blend;
+        MBGL_CHECK_ERROR(blend = glIsEnabled(GL_BLEND));
+        return blend;
+    }
+};
+
+struct BlendFunc {
+    struct Type { GLenum sfactor, dfactor; };
+    static const constexpr Type Default = { GL_ONE, GL_ONE_MINUS_SRC_ALPHA };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glBlendFunc(value.sfactor, value.dfactor));
+    }
+    static Type Get() {
+        GLint sfactor, dfactor;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_BLEND_SRC_ALPHA, &sfactor));
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_BLEND_DST_ALPHA, &dfactor));
+        return { static_cast<GLenum>(sfactor), static_cast<GLenum>(dfactor) };
+    }
+};
+
+constexpr bool operator!=(const BlendFunc::Type& a, const BlendFunc::Type& b) {
+    return a.sfactor != b.sfactor || a.dfactor != b.dfactor;
+}
+
+struct BlendColor {
+    using Type = Color;
+    static const constexpr Type Default = { 0, 0, 0, 0 };
+    inline static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glBlendColor(value.r, value.g, value.b, value.a));
+    }
+    inline static Type Get() {
+        GLfloat floats[4];
+        MBGL_CHECK_ERROR(glGetFloatv(GL_BLEND_COLOR, floats));
+        return { floats[0], floats[1], floats[2], floats[3] };
+    }
+};
+
+struct Program {
+    using Type = GLuint;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glUseProgram(value));
+    }
+    static Type Get() {
+        GLint program;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_CURRENT_PROGRAM, &program));
+        return program;
+    }
+};
+
+struct LineWidth {
+    using Type = GLfloat;
+    static const constexpr Type Default = 1;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glLineWidth(value));
+    }
+    static Type Get() {
+        Type lineWidth;
+        MBGL_CHECK_ERROR(glGetFloatv(GL_LINE_WIDTH, &lineWidth));
+        return lineWidth;
+    }
+};
+
+struct ActiveTexture {
+    using Type = uint8_t;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glActiveTexture(GL_TEXTURE0 + value));
+    }
+    static Type Get() {
+        GLint activeTexture;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_ACTIVE_TEXTURE, &activeTexture));
+        return activeTexture - GL_TEXTURE0;
+    }
+};
+
+struct BindFramebuffer {
+    using Type = GLint;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glBindFramebuffer(GL_FRAMEBUFFER, value));
+    }
+    static Type Get() {
+        Type activeFBO;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_FRAMEBUFFER_BINDING, &activeFBO));
+        return activeFBO;
+    }
+};
+
+struct Viewport {
+    using Type = std::array<GLint, 4>;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glViewport(value[0], value[1], value[2], value[3]));
+    }
+    static Type Get() {
+        Type pos;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_VIEWPORT, pos.data()));
+        return pos;
+    }
+};
+
+
+#ifndef GL_ES_VERSION_2_0
+
+struct PixelZoom {
+    struct Type { GLfloat xfactor; GLfloat yfactor; };
+    static const constexpr Type Default = { 1, 1 };
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glPixelZoom(value.xfactor, value.yfactor));
+    }
+    static Type Get() {
+        Type value;
+        MBGL_CHECK_ERROR(glGetFloatv(GL_ZOOM_X, &value.xfactor));
+        MBGL_CHECK_ERROR(glGetFloatv(GL_ZOOM_Y, &value.yfactor));
+        return value;
+    }
+};
+
+constexpr bool operator!=(const PixelZoom::Type& a, const PixelZoom::Type& b) {
+    return a.xfactor != b.xfactor || a.yfactor != b.yfactor;
+}
+
+struct RasterPos {
+    using Type = std::array<GLdouble, 4>;
+    static const constexpr Type Default = {{ 0, 0, 0, 0 }};
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glRasterPos4d(value[0], value[1], value[2], value[3]));
+    }
+    static Type Get() {
+        Type pos;
+        MBGL_CHECK_ERROR(glGetDoublev(GL_CURRENT_RASTER_POSITION, pos.data()));
+        return pos;
+    }
+};
+
+#endif // GL_ES_VERSION_2_0
+
+struct BindTexture {
+    using Type = GLuint;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glBindTexture(GL_TEXTURE_2D, value));
+    }
+    static Type Get() {
+        GLint texture;
+        MBGL_CHECK_ERROR(glGetIntegerv(GL_TEXTURE_BINDING_2D, &texture));
+        return texture;
+    }
+};
+
+template <GLenum target>
+struct BindBuffer {
+    static_assert(target == GL_ARRAY_BUFFER || target == GL_ELEMENT_ARRAY_BUFFER,
+                  "target must be one of GL_ARRAY_BUFFER or GL_ELEMENT_ARRAY_BUFFER");
+    using Type = GLuint;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        MBGL_CHECK_ERROR(glBindBuffer(target, value));
+    }
+    static Type Get() {
+        GLint binding;
+        MBGL_CHECK_ERROR(glGetIntegerv(target == GL_ARRAY_BUFFER ? GL_ARRAY_BUFFER_BINDING
+                                                                 : GL_ELEMENT_ARRAY_BUFFER_BINDING,
+                                       &binding));
+        return binding;
+    }
+};
+
+template <GLenum target>
+const typename BindBuffer<target>::Type BindBuffer<target>::Default;
+
+struct BindVAO {
+    using Type = GLuint;
+    static const constexpr Type Default = 0;
+    static void Set(const Type& value) {
+        if (gl::BindVertexArray) {
+            MBGL_CHECK_ERROR(gl::BindVertexArray(value));
+        }
+    }
+};
+
+
+} // namespace value
+} // namespace gl
+} // namespace mbgl