glview_example_01.c
#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_MAIN int
elm_main(int argc, char **argv)
{
Evas_Object *win, *bx, *bt, *gl;
Ecore_Animator *ani;
GLData *gld = NULL;
if (!(gld = calloc(1, sizeof(GLData)))) return 1;
elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);
win = elm_win_util_standard_add("glview simple", "GLView Simple");
elm_win_autodel_set(win, EINA_TRUE);
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()