1 files changed, 114 insertions, 0 deletions
diff --git a/test/gl/context.test.cpp b/test/gl/context.test.cpp
new file mode 100644
index 0000000000..179ce5de53
--- /dev/null
+++ b/test/gl/context.test.cpp
@@ -0,0 +1,114 @@
+#include <mbgl/test/util.hpp>
+
+#include <mbgl/gl/gl.hpp>
+#include <mbgl/gl/context.hpp>
+#include <mbgl/map/map.hpp>
+#include <mbgl/util/default_thread_pool.hpp>
+#include <mbgl/storage/default_file_source.hpp>
+#include <mbgl/gl/headless_frontend.hpp>
+#include <mbgl/style/style.hpp>
+#include <mbgl/style/layers/custom_layer.hpp>
+#include <mbgl/style/layers/fill_layer.hpp>
+#include <mbgl/style/layers/background_layer.hpp>
+#include <mbgl/util/io.hpp>
+#include <mbgl/util/mat4.hpp>
+#include <mbgl/util/run_loop.hpp>
+
+using namespace mbgl;
+using namespace mbgl::style;
+
+static const GLchar* vertexShaderSource = R"MBGL_SHADER(
+#ifdef GL_ES
+precision mediump float;
+#endif
+attribute vec2 a_pos;
+void main() {
+    gl_Position = vec4(a_pos, 0, 1);
+}
+)MBGL_SHADER";
+
+static const GLchar* fragmentShaderSource = R"MBGL_SHADER(
+#ifdef GL_ES
+precision mediump float;
+#endif
+void main() {
+    gl_FragColor = vec4(0, 1, 0, 1);
+}
+)MBGL_SHADER";
+
+struct Shader {
+    Shader(const GLchar* vertex, const GLchar* fragment) {
+        program = MBGL_CHECK_ERROR(glCreateProgram());
+        vertexShader = MBGL_CHECK_ERROR(glCreateShader(GL_VERTEX_SHADER));
+        fragmentShader = MBGL_CHECK_ERROR(glCreateShader(GL_FRAGMENT_SHADER));
+        MBGL_CHECK_ERROR(glShaderSource(vertexShader, 1, &vertex, nullptr));
+        MBGL_CHECK_ERROR(glCompileShader(vertexShader));
+        MBGL_CHECK_ERROR(glAttachShader(program, vertexShader));
+        MBGL_CHECK_ERROR(glShaderSource(fragmentShader, 1, &fragment, nullptr));
+        MBGL_CHECK_ERROR(glCompileShader(fragmentShader));
+        MBGL_CHECK_ERROR(glAttachShader(program, fragmentShader));
+        MBGL_CHECK_ERROR(glLinkProgram(program));
+        a_pos = MBGL_CHECK_ERROR(glGetAttribLocation(program, "a_pos"));
+    }
+
+    ~Shader() {
+        MBGL_CHECK_ERROR(glDetachShader(program, vertexShader));
+        MBGL_CHECK_ERROR(glDetachShader(program, fragmentShader));
+        MBGL_CHECK_ERROR(glDeleteShader(vertexShader));
+        MBGL_CHECK_ERROR(glDeleteShader(fragmentShader));
+        MBGL_CHECK_ERROR(glDeleteProgram(program));
+    }
+
+    GLuint program = 0;
+    GLuint vertexShader = 0;
+    GLuint fragmentShader = 0;
+    GLuint a_pos = 0;
+};
+
+struct Buffer {
+    Buffer(std::vector<GLfloat> data) {
+        MBGL_CHECK_ERROR(glGenBuffers(1, &buffer));
+        MBGL_CHECK_ERROR(glBindBuffer(GL_ARRAY_BUFFER, buffer));
+        MBGL_CHECK_ERROR(glBufferData(GL_ARRAY_BUFFER, data.size() * sizeof(GLfloat), data.data(),
+                                      GL_STATIC_DRAW));
+    }
+
+    ~Buffer() {
+        MBGL_CHECK_ERROR(glDeleteBuffers(1, &buffer));
+    }
+
+    GLuint buffer = 0;
+};
+
+TEST(GLContextMode, Shared) {
+    util::RunLoop loop;
+
+    DefaultFileSource fileSource(":memory:", "test/fixtures/api/assets");
+    ThreadPool threadPool(4);
+    float pixelRatio { 1 };
+
+    HeadlessFrontend frontend { pixelRatio, fileSource, threadPool, {}, GLContextMode::Shared };
+
+    Map map(frontend, MapObserver::nullObserver(), frontend.getSize(), pixelRatio, fileSource, threadPool, MapMode::Static);
+    map.getStyle().loadJSON(util::read_file("test/fixtures/api/water.json"));
+    map.setLatLngZoom({ 37.8, -122.5 }, 10);
+
+    // Set transparent background layer.
+    map.getStyle().getLayer("background")->as<BackgroundLayer>()->setBackgroundColor( { { 1.0f, 0.0f, 0.0f, 0.5f } } );
+
+    {
+        // Custom rendering outside of GL Native render loop.
+        BackendScope scope { *frontend.getBackend() };
+        frontend.getBackend()->bind();
+
+        Shader paintShader(vertexShaderSource, fragmentShaderSource);
+        Buffer triangleBuffer({ 0, 0.5, 0.5, -0.5, -0.5, -0.5 });
+        MBGL_CHECK_ERROR(glUseProgram(paintShader.program));
+        MBGL_CHECK_ERROR(glBindBuffer(GL_ARRAY_BUFFER, triangleBuffer.buffer));
+        MBGL_CHECK_ERROR(glEnableVertexAttribArray(paintShader.a_pos));
+        MBGL_CHECK_ERROR(glVertexAttribPointer(paintShader.a_pos, 2, GL_FLOAT, GL_FALSE, 0, nullptr));
+        MBGL_CHECK_ERROR(glDrawArrays(GL_TRIANGLE_STRIP, 0, 3));
+    }
+
+    test::checkImage("test/fixtures/shared_context", frontend.render(map), 0.5, 0.1);
+}