efl

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