+/**
+ * Simple Elementary's <b>GLView widget</b> example, illustrating its
+ * creation.
+ *
+ * See stdout/stderr for output. Compile with:
+ *
+ * @verbatim
+ * gcc -o glview_example_01 glview_example_01.c -g `pkg-config --cflags --libs elementary`
+ * @endverbatim
+ */
+#include <Elementary.h>
+#include <Evas_GL.h>
+#include <stdio.h>
+
+typedef struct _GLData GLData;
+
+// GL related data here..
+struct _GLData
+{
+ Evas_GL_API *glapi;
+ GLuint program;
+ GLuint vtx_shader;
+ GLuint fgmt_shader;
+ GLuint vbo;
+ int initialized : 1;
+};
+
+static float red = 1.0;
+
+//--------------------------------//
+// a helper function to load shaders from a shader source
+static GLuint
+load_shader( GLData *gld, GLenum type, const char *shader_src )
+{
+ Evas_GL_API *gl = gld->glapi;
+ GLuint shader;
+ GLint compiled;
+
+ // Create the shader object
+ shader = gl->glCreateShader(type);
+ if (shader==0)
+ return 0;
+
+ // Load/Compile shader source
+ gl->glShaderSource(shader, 1, &shader_src, NULL);
+ gl->glCompileShader(shader);
+ gl->glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+
+ if (!compiled)
+ {
+ GLint info_len = 0;
+ gl->glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &info_len);
+ if (info_len > 1)
+ {
+ char* info_log = malloc(sizeof(char) * info_len);
+
+ gl->glGetShaderInfoLog(shader, info_len, NULL, info_log);
+ printf("Error compiling shader:\n%s\n======\n%s\n======\n", info_log, shader_src );
+ free(info_log);
+ }
+ gl->glDeleteShader(shader);
+ return 0;
+ }
+
+ return shader;
+}
+
+// Initialize the shader and program object
+static int
+init_shaders(GLData *gld)
+{
+ Evas_GL_API *gl = gld->glapi;
+ GLbyte vShaderStr[] =
+ "attribute vec4 vPosition; \n"
+ "void main() \n"
+ "{ \n"
+ " gl_Position = vPosition; \n"
+ "} \n";
+
+ GLbyte fShaderStr[] =
+ "#ifdef GL_ES \n"
+ "precision mediump float; \n"
+ "#endif \n"
+ "void main() \n"
+ "{ \n"
+ " gl_FragColor = vec4 ( 1.0, 0.0, 0.0, 1.0 );\n"
+ "} \n";
+
+ GLint linked;
+
+ // Load the vertex/fragment shaders
+ gld->vtx_shader = load_shader(gld, GL_VERTEX_SHADER, (const char*)vShaderStr);
+ gld->fgmt_shader = load_shader(gld, GL_FRAGMENT_SHADER, (const char*)fShaderStr);
+
+ // Create the program object
+ gld->program = gl->glCreateProgram( );
+ if (gld->program==0)
+ return 0;
+
+ gl->glAttachShader(gld->program, gld->vtx_shader);
+ gl->glAttachShader(gld->program, gld->fgmt_shader);
+
+ gl->glBindAttribLocation(gld->program, 0, "vPosition");
+ gl->glLinkProgram(gld->program);
+ gl->glGetProgramiv(gld->program, GL_LINK_STATUS, &linked);
+
+ if (!linked)
+ {
+ GLint info_len = 0;
+ gl->glGetProgramiv(gld->program, GL_INFO_LOG_LENGTH, &info_len);
+ if (info_len > 1)
+ {
+ char* info_log = malloc(sizeof(char) * info_len);
+
+ gl->glGetProgramInfoLog(gld->program, info_len, NULL, info_log);
+ printf("Error linking program:\n%s\n", info_log);
+ free(info_log);
+ }
+ gl->glDeleteProgram(gld->program);
+ return 0;
+ }
+ return 1;
+}
+
+
+
+// Callbacks
+// intialize callback that gets called once for intialization
+static void
+_init_gl(Evas_Object *obj)
+{
+ GLData *gld = evas_object_data_get(obj, "gld");
+ Evas_GL_API *gl = gld->glapi;
+ GLfloat vVertices[] = { 0.0f, 0.5f, 0.0f,
+ -0.5f, -0.5f, 0.0f,
+ 0.5f, -0.5f, 0.0f };
+
+ if (!init_shaders(gld))
+ {
+ printf("Error Initializing Shaders\n");
+ return;
+ }
+
+ gl->glGenBuffers(1, &gld->vbo);
+ gl->glBindBuffer(GL_ARRAY_BUFFER, gld->vbo);
+ gl->glBufferData(GL_ARRAY_BUFFER, 3 * 3 * 4, vVertices, GL_STATIC_DRAW);
+}
+
+// delete callback gets called when glview is deleted
+static void
+_del_gl(Evas_Object *obj)
+{
+ GLData *gld = evas_object_data_get(obj, "gld");
+ if (!gld)
+ {
+ printf("Unable to get GLData. \n");
+ return;
+ }
+ Evas_GL_API *gl = gld->glapi;
+
+ gl->glDeleteShader(gld->vtx_shader);
+ gl->glDeleteShader(gld->fgmt_shader);
+ gl->glDeleteProgram(gld->program);
+ gl->glDeleteBuffers(1, &gld->vbo);
+
+ evas_object_data_del((Evas_Object*)obj, "..gld");
+ free(gld);
+}
+
+// resize callback gets called every time object is resized
+static void
+_resize_gl(Evas_Object *obj)
+{
+ int w, h;
+ GLData *gld = evas_object_data_get(obj, "gld");
+ Evas_GL_API *gl = gld->glapi;
+
+ elm_glview_size_get(obj, &w, &h);
+
+ // GL Viewport stuff. you can avoid doing this if viewport is all the
+ // same as last frame if you want
+ gl->glViewport(0, 0, w, h);
+}
+
+
+// draw callback is where all the main GL rendering happens
+static void
+_draw_gl(Evas_Object *obj)
+{
+ Evas_GL_API *gl = elm_glview_gl_api_get(obj);
+ GLData *gld = evas_object_data_get(obj, "gld");
+ if (!gld) return;
+ int w, h;
+
+ elm_glview_size_get(obj, &w, &h);
+
+ gl->glViewport(0, 0, w, h);
+ gl->glClearColor(red,0.8,0.3,1);
+ gl->glClear(GL_COLOR_BUFFER_BIT);
+
+ // Draw a Triangle
+ gl->glEnable(GL_BLEND);
+
+ gl->glUseProgram(gld->program);
+
+ gl->glBindBuffer(GL_ARRAY_BUFFER, gld->vbo);
+ gl->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
+ 0, 0);
+ gl->glEnableVertexAttribArray(0);
+
+ gl->glDrawArrays(GL_TRIANGLES, 0, 3);
+
+ // Optional - Flush the GL pipeline
+ gl->glFinish();
+
+ red -= 0.1;
+ if (red < 0.0) red = 1.0;
+}
+
+// just need to notify that glview has changed so it can render
+static Eina_Bool
+_anim(void *data)
+{
+ elm_glview_changed_set(data);
+ return EINA_TRUE;
+}
+
+static void
+_on_done(void *data, Evas_Object *obj, void *event_info)
+{
+ evas_object_del((Evas_Object*)data);
+ elm_exit();
+}
+
+static void
+_del(void *data, Evas *evas, Evas_Object *obj, void *event_info)
+{
+ Ecore_Animator *ani = evas_object_data_get(obj, "ani");
+ ecore_animator_del(ani);
+}
+
+
+EAPI int
+elm_main(int argc, char **argv)
+{
+ Evas_Object *win, *bg, *bx, *bt, *gl;
+ Ecore_Animator *ani;
+ GLData *gld = NULL;
+
+ if (!(gld = calloc(1, sizeof(GLData)))) return 1;
+
+ // set the engine to opengl_x11
+ // if commented out, ELM will choose one
+ elm_config_engine_set("opengl_x11");
+
+ win = elm_win_add(NULL, "glview simple", ELM_WIN_BASIC);
+ elm_win_title_set(win, "GLView Simple");
+ elm_win_autodel_set(win, EINA_TRUE);
+ elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);
+
+ bg = elm_bg_add(win);
+ elm_win_resize_object_add(win, bg);
+ evas_object_size_hint_weight_set(bg, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
+ evas_object_show(bg);
+
+ bx = elm_box_add(win);
+ evas_object_size_hint_weight_set(bx, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
+ elm_win_resize_object_add(win, bx);
+ evas_object_show(bx);
+
+ //-//-//-// THIS IS WHERE GL INIT STUFF HAPPENS (ALA EGL)
+ //-//
+ // create a new glview object
+ gl = elm_glview_add(win);
+ gld->glapi = elm_glview_gl_api_get(gl);
+ evas_object_size_hint_align_set(gl, EVAS_HINT_FILL, EVAS_HINT_FILL);
+ evas_object_size_hint_weight_set(gl, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
+ // mode is simply for supporting alpha, depth buffering, and stencil
+ // buffering.
+ elm_glview_mode_set(gl, ELM_GLVIEW_ALPHA | ELM_GLVIEW_DEPTH);
+ // resize policy tells glview what to do with the surface when it
+ // resizes. ELM_GLVIEW_RESIZE_POLICY_RECREATE will tell it to
+ // destroy the current surface and recreate it to the new size
+ elm_glview_resize_policy_set(gl, ELM_GLVIEW_RESIZE_POLICY_RECREATE);
+ // render policy tells glview how it would like glview to render
+ // gl code. ELM_GLVIEW_RENDER_POLICY_ON_DEMAND will have the gl
+ // calls called in the pixel_get callback, which only gets called
+ // if the object is visible, hence ON_DEMAND. ALWAYS mode renders
+ // it despite the visibility of the object.
+ elm_glview_render_policy_set(gl, ELM_GLVIEW_RENDER_POLICY_ON_DEMAND);
+ // initialize callback function gets registered here
+ elm_glview_init_func_set(gl, _init_gl);
+ // delete callback function gets registered here
+ elm_glview_del_func_set(gl, _del_gl);
+ elm_glview_resize_func_set(gl, _resize_gl);
+ elm_glview_render_func_set(gl, _draw_gl);
+ //-//
+ //-//-//-// END GL INIT BLOB
+
+ elm_box_pack_end(bx, gl);
+ evas_object_show(gl);
+
+ elm_object_focus_set(gl, EINA_TRUE);
+
+ // animating - just a demo. as long as you trigger an update on the image
+ // object via elm_glview_changed_set() it will be updated.
+ //
+ // NOTE: if you delete gl, this animator will keep running trying to access
+ // gl so you'd better delete this animator with ecore_animator_del().
+ ani = ecore_animator_add(_anim, gl);
+
+ evas_object_data_set(gl, "ani", ani);
+ evas_object_data_set(gl, "gld", gld);
+ evas_object_event_callback_add(gl, EVAS_CALLBACK_DEL, _del, gl);
+
+ // add an 'OK' button to end the program
+ bt = elm_button_add(win);
+ elm_object_text_set(bt, "OK");
+ evas_object_size_hint_align_set(bt, EVAS_HINT_FILL, EVAS_HINT_FILL);
+ evas_object_size_hint_weight_set(bt, EVAS_HINT_EXPAND, 0.0);
+ elm_box_pack_end(bx, bt);
+ evas_object_show(bt);
+ evas_object_smart_callback_add(bt, "clicked", _on_done, win);
+
+ evas_object_resize(win, 320, 480);
+ evas_object_show(win);
+
+ // run the mainloop and process events and callbacks
+ elm_run();
+ return 0;
+}
+ELM_MAIN()