Added EGL interface for backends.

2 files changed, 170 insertions, 0 deletions

diff --git a/backend/CMakeLists.txt b/backend/CMakeLists.txt
index ee8b04d6..938dc1ab 100644
--- a/backend/CMakeLists.txt
+++ b/backend/CMakeLists.txt
@@ -12,6 +12,7 @@ add_library(wlr-backend
     drm/backend.c
     drm/drm.c
     drm/udev.c
+    egl.c
 )
 
 target_link_libraries(wlr-backend
diff --git a/backend/egl.c b/backend/egl.c
new file mode 100644
index 00000000..b6c49846
--- /dev/null
+++ b/backend/egl.c
@@ -0,0 +1,169 @@
+#include <EGL/egl.h>
+#include <EGL/eglext.h>
+#include <gbm.h> // GBM_FORMAT_XRGB8888
+
+#include "backend/egl.h"
+#include "common/log.h"
+
+static const char *egl_error(void) {
+	switch (eglGetError()) {
+	case EGL_SUCCESS:
+		return "Success";
+	case EGL_NOT_INITIALIZED:
+		return "Not initialized";
+	case EGL_BAD_ACCESS:
+		return "Bad access";
+	case EGL_BAD_ALLOC:
+		return "Bad alloc";
+	case EGL_BAD_ATTRIBUTE:
+		return "Bad attribute";
+	case EGL_BAD_CONTEXT:
+		return "Bad Context";
+	case EGL_BAD_CONFIG:
+		return "Bad Config";
+	case EGL_BAD_CURRENT_SURFACE:
+		return "Bad current surface";
+	case EGL_BAD_DISPLAY:
+		return "Bad display";
+	case EGL_BAD_SURFACE:
+		return "Bad surface";
+	case EGL_BAD_MATCH:
+		return "Bad match";
+	case EGL_BAD_PARAMETER:
+		return "Bad parameter";
+	case EGL_BAD_NATIVE_PIXMAP:
+		return "Bad native pixmap";
+	case EGL_BAD_NATIVE_WINDOW:
+		return "Bad native window";
+	case EGL_CONTEXT_LOST:
+		return "Context lost";
+	default:
+		return "Unknown";
+	}
+}
+
+// EGL extensions
+PFNEGLGETPLATFORMDISPLAYEXTPROC get_platform_display;
+PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC create_platform_window_surface;
+
+static bool egl_exts() {
+	get_platform_display = (PFNEGLGETPLATFORMDISPLAYEXTPROC)
+		eglGetProcAddress("eglGetPlatformDisplayEXT");
+
+	if (!get_platform_display) {
+		wlr_log(L_ERROR, "Failed to load EGL extension 'eglGetPlatformDisplayEXT'");
+		return false;
+	}
+
+	create_platform_window_surface = (PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC)
+		eglGetProcAddress("eglCreatePlatformWindowSurfaceEXT");
+
+	if (!get_platform_display) {
+		wlr_log(L_ERROR,
+			"Failed to load EGL extension 'eglCreatePlatformWindowSurfaceEXT'");
+		return false;
+	}
+
+	return true;
+}
+
+static bool egl_get_config(EGLDisplay disp, EGLConfig *out) {
+	EGLint count = 0, matched = 0, ret;
+
+	ret = eglGetConfigs(disp, NULL, 0, &count);
+	if (ret == EGL_FALSE || count == 0) {
+		return false;
+	}
+
+	EGLConfig configs[count];
+
+	ret = eglChooseConfig(disp, NULL, configs, count, &matched);
+	if (ret == EGL_FALSE) {
+		return false;
+	}
+
+	for (int i = 0; i < matched; ++i) {
+		EGLint gbm_format;
+
+		if (!eglGetConfigAttrib(disp,
+					configs[i],
+					EGL_NATIVE_VISUAL_ID,
+					&gbm_format)) {
+			continue;
+		}
+
+		// XXX: Is GBM_FORMAT_XRGB8888 what we want?
+		// I don't know if this works for wl_displays.
+		if (gbm_format == GBM_FORMAT_XRGB8888) {
+			*out = configs[i];
+			return true;
+		}
+	}
+
+	return false;
+}
+
+
+bool wlr_egl_init(struct wlr_egl *egl, EGLenum platform, void *display) {
+	if (!egl_exts()) {
+		return false;
+	}
+	
+	if (eglBindAPI(EGL_OPENGL_ES_API) == EGL_FALSE) {
+		wlr_log(L_ERROR, "Failed to bind to the OpenGL ES API: %s", egl_error());
+		goto error;
+	}
+
+	egl->display = get_platform_display(platform, display, NULL);
+	if (egl->display == EGL_NO_DISPLAY) {
+		wlr_log(L_ERROR, "Failed to create EGL display: %s", egl_error());
+		goto error;
+	}
+
+	if (eglInitialize(egl->display, NULL, NULL) == EGL_FALSE) {
+		wlr_log(L_ERROR, "Failed to initialize EGL: %s", egl_error());
+		goto error;
+	}
+
+	if (!egl_get_config(egl->display, &egl->config)) {
+		wlr_log(L_ERROR, "Failed to get EGL config");
+		goto error;
+	}
+
+	static const EGLint attribs[] = {EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE};
+
+	egl->context = eglCreateContext(egl->display, egl->config,
+		EGL_NO_CONTEXT, attribs);
+
+	if (egl->context == EGL_NO_CONTEXT) {
+		wlr_log(L_ERROR, "Failed to create EGL context: %s", egl_error());
+		goto error;
+	}
+
+	return true;
+
+error:
+	eglTerminate(egl->display);
+	eglReleaseThread();
+	eglMakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+
+	return false;
+}
+
+void wlr_egl_free(struct wlr_egl *egl) {
+	eglDestroyContext(egl->display, egl->context);
+	eglTerminate(egl->display);
+	eglReleaseThread();
+	eglMakeCurrent(EGL_NO_DISPLAY, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);	
+}
+
+EGLSurface wlr_egl_create_surface(struct wlr_egl *egl, void *window) {
+	EGLSurface surf = create_platform_window_surface(egl->display, egl->config,
+		window, NULL);
+	if (surf == EGL_NO_SURFACE) {
+		wlr_log(L_ERROR, "Failed to create EGL surface: %s", egl_error());
+		return EGL_NO_SURFACE;
+	}
+
+	return surf;
+}