X-Git-Url: https://git.ralfj.de/gltest.git/blobdiff_plain/141fa68c418105e1e60788f676cd7f6dcf9cbeb1..ce1b46da645fdcac80fc9c71082bb5cb40166576:/eglbackend.cpp

diff --git a/eglbackend.cpp b/eglbackend.cpp
index 0e4c937..0d765e9 100644
--- a/eglbackend.cpp
+++ b/eglbackend.cpp
@@ -17,6 +17,7 @@
  */
 
 #include "eglbackend.h"
+#include "glutil.h"
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -24,6 +25,10 @@
 
 #include <EGL/eglext.h>
 
+#if !defined(CON_GL1) && !defined(CON_GLES2)
+#error "Valid GL contexts for EGL are: GL1, GLES2"
+#endif
+
 static const char *eglErrorToString(EGLint e)
 {
 #define CASE(name) case name: return #name
@@ -49,15 +54,23 @@ static void exitEglError(const char *what)
 	exit(1);
 }
 
-/* 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,
+#endif
+	EGL_NONE
+};
 
 VisualID EGLBackend::initialize(Display *xDisplay)
 {
@@ -65,17 +78,32 @@ VisualID EGLBackend::initialize(Display *xDisplay)
 		// get connection and bind API
 		EGLint eglMajor, eglMinor;
 		display = eglGetDisplay(xDisplay);
-		if (display == EGL_NO_DISPLAY)                         
+		if (display == EGL_NO_DISPLAY)
 			exitEglError("Failed to get EGL display");
-		if (eglInitialize(display, &eglMajor, &eglMinor) == EGL_FALSE)                   
+		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);
+		printf("Using EGL version: %d.%d\n", eglMajor, eglMinor);
+		if (eglMajor == 1 && eglMinor < 3) {
+			// Choosing the GL context version requires EGL 1.3
+			fprintf(stderr, "Need at least EGL 1.3 to function properly\n");
+			exit(1);
+		}
+#ifdef CON_GLES2
+		if (eglBindAPI(EGL_OPENGL_ES_API) == EGL_FALSE)
+#else
+		if (eglBindAPI(EGL_OPENGL_API) == EGL_FALSE)
+#endif
+			exitEglError("Failed to bind API");
 		// 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){
+			exitEglError("Failed to choose framebuffer configuration");
+		}
+		if (count == 0) {
+			fprintf(stderr, "Found no matching framebuffer configuration\n");
+			exit(1);
+		}
 		config = configs[0];
 	}
 	// return visual ID
@@ -88,12 +116,15 @@ 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");
 	if (eglMakeCurrent(display, surface, surface, context) == EGL_FALSE)
 		exitEglError("Failed to make context current");
+	printf("Using GL version: %s\n", glGetString(GL_VERSION));
+	// initialise GL utilities
+	resolveFunctionPointers(eglGetProcAddress);
 }
 
 EGLBackend::~EGLBackend()
@@ -112,11 +143,25 @@ EGLBackend::~EGLBackend()
 void EGLBackend::swapBuffers() const
 {
 	assert(context != EGL_NO_CONTEXT); // this implies the display is also initialized
-	eglSwapBuffers(display, surface);
+	if (eglSwapBuffers(display, surface) == EGL_FALSE)
+		exitEglError("Failed to swap buffers");
 }
 
 void EGLBackend::setSwapInterval(int i) const
 {
 	assert(context != EGL_NO_CONTEXT);
-	eglSwapInterval(display, i);
+	// check if swap interval value is supported
+	if (i < 0) {
+		fprintf(stderr, "Cannot set swap interval to %d, must not be negative\n", i);
+		exit(1);
+	}
+	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);
+	}
+	// use it
+	if (eglSwapInterval(display, i) == EGL_FALSE)
+		exitEglError("Failed to set swap interval");
 }