X-Git-Url: https://git.ralfj.de/gltest.git/blobdiff_plain/92d3b1692f11658cad027cd597019eabd65faf89..7204186779e096ceab7b39f54dcf6f606062f29b:/eglbackend.cpp?ds=sidebyside

diff --git a/eglbackend.cpp b/eglbackend.cpp
index 04165c7..47e0384 100644
--- a/eglbackend.cpp
+++ b/eglbackend.cpp
@@ -17,13 +17,17 @@
  */
 
 #include "eglbackend.h"
+#include "glutil.h"
 
-#include <stdlib.h>
 #include <stdio.h>
 #include <assert.h>
 
 #include <EGL/eglext.h>
 
+#if !defined(CON_GL1) && !defined(CON_GL3) && !defined(CON_GLES2)
+#error "Valid GL contexts for EGL are: GL1, GL3, GLES2"
+#endif
+
 static const char *eglErrorToString(EGLint e)
 {
 #define CASE(name) case name: return #name
@@ -42,22 +46,33 @@ static const char *eglErrorToString(EGLint e)
 #undef CASE
 }
 
-static void exitEglError(const char *what)
+static void dieEgl(const char *what)
 {
 	EGLint e = eglGetError();
-	fprintf(stderr, "EGL error %d (%s): %s\n", e, eglErrorToString(e), what);
-	exit(1);
+	die("EGL error %d (%s): %s\n", e, eglErrorToString(e), what);
 }
 
-/* attributes for a double buffered visual in RGBA format with at least
-* 4 bits per color */
-static const EGLint config_attribs[] = {
+static const EGLint configAttribs[] = {
 	EGL_RED_SIZE,             4,
 	EGL_GREEN_SIZE,           4,
 	EGL_BLUE_SIZE,            4,
+#ifdef CON_GLES2
+	EGL_RENDERABLE_TYPE,      EGL_OPENGL_ES2_BIT,
+#else
 	EGL_RENDERABLE_TYPE,      EGL_OPENGL_BIT,
+#endif
 	EGL_NONE,
 };
+static const EGLint contextAttribs[] = {
+#ifdef CON_GLES2
+	EGL_CONTEXT_CLIENT_VERSION, 2,
+#elif CON_GL3
+	EGL_CONTEXT_MAJOR_VERSION_KHR, 3,
+	EGL_CONTEXT_MINOR_VERSION_KHR, 0,
+	EGL_CONTEXT_FLAGS_KHR, EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR,
+#endif
+	EGL_NONE
+};
 
 VisualID EGLBackend::initialize(Display *xDisplay)
 {
@@ -65,17 +80,36 @@ VisualID EGLBackend::initialize(Display *xDisplay)
 		// get connection and bind API
 		EGLint eglMajor, eglMinor;
 		display = eglGetDisplay(xDisplay);
-		if (display == EGL_NO_DISPLAY)                         
-			exitEglError("Failed to get EGL display");
-		if (eglInitialize(display, &eglMajor, &eglMinor) == EGL_FALSE)                   
-			exitEglError("Failed to initialize EGL");
-		printf("Using EGL version %d.%d\n", eglMajor, eglMinor);
-		eglBindAPI(EGL_OPENGL_API);
+		if (display == EGL_NO_DISPLAY)
+			dieEgl("Failed to get EGL display");
+		if (eglInitialize(display, &eglMajor, &eglMinor) == EGL_FALSE)
+			dieEgl("Failed to initialize EGL");
+		printf("Using EGL version: %d.%d\n", eglMajor, eglMinor);
+		if (eglMajor == 1 && eglMinor < 4) {
+			// Choosing the GL context version requires EGL 1.3, creating an OpenGL 3 context requires EGL 1.4
+			die("Need at least EGL 1.4 to function properly\n");
+		}
+#ifdef CON_GLES2
+		if (eglBindAPI(EGL_OPENGL_ES_API) == EGL_FALSE)
+#else
+		if (eglBindAPI(EGL_OPENGL_API) == EGL_FALSE)
+#endif
+			dieEgl("Failed to bind API");
+		// check for the extension we need
+#ifdef CON_GL3
+		if (!haveEGLExtension("EGL_KHR_create_context")) {
+			die("Required EGL extension EGL_KHR_create_context is not supported\n");
+		}
+#endif
 		// get an appropriate config
 		EGLConfig configs[1];
 		EGLint count;
-		if (eglChooseConfig(display, config_attribs, configs, 1, &count) == EGL_FALSE || count == 0)                            
-			exitEglError("Failed to choose config");
+		if (eglChooseConfig(display, configAttribs, configs, 1, &count) == EGL_FALSE){
+			dieEgl("Failed to choose framebuffer configuration");
+		}
+		if (count == 0) {
+			die("Found no matching framebuffer configuration\n");
+		}
 		config = configs[0];
 	}
 	// return visual ID
@@ -84,16 +118,26 @@ VisualID EGLBackend::initialize(Display *xDisplay)
 	return (VisualID)val;
 }
 
+bool EGLBackend::haveEGLExtension(const std::string &name)
+{
+	assert(display != EGL_NO_DISPLAY);
+	std::string extensions = eglQueryString(display, EGL_EXTENSIONS);
+	return (std::string(" "+extensions+" ").find(" "+name+" ") != std::string::npos);
+}
+
 void EGLBackend::createContext(Window window)
 {
 	assert(display != EGL_NO_DISPLAY && context == EGL_NO_CONTEXT);
 	surface = eglCreateWindowSurface(display, config, window, NULL);
-	/* create an EGL context and use it with the surface */                                    
-	context = eglCreateContext(display, config, EGL_NO_CONTEXT, NULL);
+	// create an EGL context and use it with the surface
+	context = eglCreateContext(display, config, EGL_NO_CONTEXT, contextAttribs);
 	if (context == EGL_NO_CONTEXT)
-		exitEglError("Failed to create context");
+		dieEgl("Failed to create context");
 	if (eglMakeCurrent(display, surface, surface, context) == EGL_FALSE)
-		exitEglError("Failed to make context current");
+		dieEgl("Failed to make context current");
+	printf("Using GL version: %s\n", glGetString(GL_VERSION));
+	// initialise GL utilities
+	resolveFunctionPointers(eglGetProcAddress);
 }
 
 EGLBackend::~EGLBackend()
@@ -113,25 +157,22 @@ void EGLBackend::swapBuffers() const
 {
 	assert(context != EGL_NO_CONTEXT); // this implies the display is also initialized
 	if (eglSwapBuffers(display, surface) == EGL_FALSE)
-		exitEglError("Failed to swap buffers");
+		dieEgl("Failed to swap buffers");
 }
 
 void EGLBackend::setSwapInterval(int i) const
 {
 	assert(context != EGL_NO_CONTEXT);
 	// check if swap interval value is supported
-	EGLint val;
-	eglGetConfigAttrib(display, config, EGL_MIN_SWAP_INTERVAL, &val);
-	if (i < val) {
-		fprintf(stderr, "Cannot set swap interval to %d, minimum supported value is %d\n", i, val);
-		exit(1);
+	if (i < 0) {
+		die("Cannot set swap interval to %d, must not be negative\n", i);
 	}
+	EGLint val;
 	eglGetConfigAttrib(display, config, EGL_MAX_SWAP_INTERVAL, &val);
 	if (i > val) {
-		fprintf(stderr, "Cannot set swap interval to %d, maximum supported value is %d\n", i, val);
-		exit(1);
+		die("Cannot set swap interval to %d, maximum supported value is %d\n", i, val);
 	}
 	// use it
 	if (eglSwapInterval(display, i) == EGL_FALSE)
-		exitEglError("Failed to set swap interval");
+		dieEgl("Failed to set swap interval");
 }