mutter/examples/cogl-crate.c
Neil Roberts dedee399d6 Rotate according to time not number of frames in the crate example
Previously the crate example incremented the angle of rotation of the
cube every frame so depending on the framerate the cube might rotate
too fast to see. This just changes it to calculate the rotation based
on the elapsed time using a GTimer. The rate that frames are drawn is
unaffected.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
2011-10-17 13:57:29 +01:00

282 lines
10 KiB
C

#include <cogl/cogl.h>
#include <cogl-pango/cogl-pango.h>
/* The state for this example... */
typedef struct _Data
{
int framebuffer_width;
int framebuffer_height;
CoglMatrix view;
CoglPrimitive *prim;
CoglTexture *texture;
CoglPipeline *crate_pipeline;
CoglPangoFontMap *pango_font_map;
PangoContext *pango_context;
PangoFontDescription *pango_font_desc;
PangoLayout *hello_label;
int hello_label_width;
int hello_label_height;
GTimer *timer;
} Data;
/* A static identity matrix initialized for convenience. */
static CoglMatrix identity;
/* static colors initialized for convenience. */
static CoglColor black;
static CoglColor white;
/* A cube modelled as a list of triangles. Potentially this could be
* done more efficiently as a triangle strip or using a separate index
* array, but this way is pretty simple, if a little verbose. */
CoglVertexP3T2 vertices[] =
{
/* Front face */
{ /* pos = */ -1.0f, -1.0f, 1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, 1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ -1.0f, -1.0f, 1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ -1.0f, 1.0f, 1.0f, /* tex coords = */ 0.0f, 0.0f},
/* Back face */
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ -1.0f, 1.0f, -1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ 1.0f, 1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ 1.0f, 1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, -1.0f, /* tex coords = */ 0.0f, 0.0f},
/* Top face */
{ /* pos = */ -1.0f, 1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ -1.0f, 1.0f, 1.0f, /* tex coords = */ 0.0f, 0.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ -1.0f, 1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ 1.0f, 1.0f, -1.0f, /* tex coords = */ 1.0f, 1.0f},
/* Bottom face */
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, 1.0f, /* tex coords = */ 0.0f, 0.0f},
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, 1.0f, /* tex coords = */ 0.0f, 0.0f},
{ /* pos = */ -1.0f, -1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
/* Right face */
{ /* pos = */ 1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ 1.0f, 1.0f, -1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, -1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ 1.0f, 1.0f, 1.0f, /* tex coords = */ 0.0f, 1.0f},
{ /* pos = */ 1.0f, -1.0f, 1.0f, /* tex coords = */ 0.0f, 0.0f},
/* Left face */
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 0.0f, 0.0f},
{ /* pos = */ -1.0f, -1.0f, 1.0f, /* tex coords = */ 1.0f, 0.0f},
{ /* pos = */ -1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ -1.0f, -1.0f, -1.0f, /* tex coords = */ 0.0f, 0.0f},
{ /* pos = */ -1.0f, 1.0f, 1.0f, /* tex coords = */ 1.0f, 1.0f},
{ /* pos = */ -1.0f, 1.0f, -1.0f, /* tex coords = */ 0.0f, 1.0f}
};
static void
paint (Data *data)
{
float rotation;
cogl_clear (&black, COGL_BUFFER_BIT_COLOR|COGL_BUFFER_BIT_DEPTH);
cogl_push_matrix ();
cogl_translate (data->framebuffer_width / 2, data->framebuffer_height / 2, 0);
cogl_scale (75, 75, 75);
/* Update the rotation based on the time the application has been
running so that we get a linear animation regardless of the frame
rate */
rotation = g_timer_elapsed (data->timer, NULL) * 60.0f;
/* Rotate the cube separately around each axis.
*
* Note: Cogl matrix manipulation follows the same rules as for
* OpenGL. We use column-major matrices and - if you consider the
* transformations happening to the model - then they are combined
* in reverse order which is why the rotation is done last, since
* we want it to be a rotation around the origin, before it is
* scaled and translated.
*/
cogl_rotate (rotation, 0, 0, 1);
cogl_rotate (rotation, 0, 1, 0);
cogl_rotate (rotation, 1, 0, 0);
/* Whenever you draw something with Cogl using geometry defined by
* one of cogl_rectangle, cogl_polygon, cogl_path or
* cogl_vertex_buffer then you have a current pipeline that defines
* how that geometry should be processed.
*
* Here we are making our crate pipeline current which will sample
* the crate texture when fragment processing. */
cogl_set_source (data->crate_pipeline);
/* Give Cogl some geometry to draw. */
cogl_primitive_draw (data->prim);
cogl_set_depth_test_enabled (FALSE);
cogl_pop_matrix ();
/* And finally render our Pango layouts... */
cogl_pango_render_layout (data->hello_label,
(data->framebuffer_width / 2) -
(data->hello_label_width / 2),
(data->framebuffer_height / 2) -
(data->hello_label_height / 2),
&white, 0);
}
int
main (int argc, char **argv)
{
CoglContext *ctx;
CoglOnscreen *onscreen;
CoglFramebuffer *fb;
GError *error = NULL;
Data data;
PangoRectangle hello_label_size;
float fovy, aspect, z_near, z_2d, z_far;
CoglDepthState depth_state;
g_type_init ();
ctx = cogl_context_new (NULL, &error);
if (!ctx) {
fprintf (stderr, "Failed to create context: %s\n", error->message);
return 1;
}
data.framebuffer_width = 640;
data.framebuffer_height = 480;
onscreen = cogl_onscreen_new (ctx, data.framebuffer_width, data.framebuffer_height);
/* Eventually there will be an implicit allocate on first use so this
* will become optional... */
fb = COGL_FRAMEBUFFER (onscreen);
if (!cogl_framebuffer_allocate (fb, &error)) {
fprintf (stderr, "Failed to allocate framebuffer: %s\n", error->message);
return 1;
}
data.timer = g_timer_new ();
cogl_onscreen_show (onscreen);
cogl_push_framebuffer (fb);
cogl_set_viewport (0, 0, data.framebuffer_width, data.framebuffer_height);
fovy = 60; /* y-axis field of view */
aspect = (float)data.framebuffer_width/(float)data.framebuffer_height;
z_near = 0.1; /* distance to near clipping plane */
z_2d = 1000; /* position to 2d plane */
z_far = 2000; /* distance to far clipping plane */
cogl_perspective (fovy, aspect, z_near, z_far);
/* Since the pango renderer emits geometry in pixel/device coordinates
* and the anti aliasing is implemented with the assumption that the
* geometry *really* does end up pixel aligned, we setup a modelview
* matrix so that for geometry in the plane z = 0 we exactly map x
* coordinates in the range [0,stage_width] and y coordinates in the
* range [0,stage_height] to the framebuffer extents with (0,0) being
* the top left.
*
* This is roughly what Clutter does for a ClutterStage, but this
* demonstrates how it is done manually using Cogl.
*/
cogl_matrix_init_identity (&data.view);
cogl_matrix_view_2d_in_perspective (&data.view, fovy, aspect, z_near, z_2d,
data.framebuffer_width,
data.framebuffer_height);
cogl_set_modelview_matrix (&data.view);
cogl_pop_framebuffer ();
/* Initialize some convenient constants */
cogl_matrix_init_identity (&identity);
cogl_color_set_from_4ub (&black, 0x00, 0x00, 0x00, 0xff);
cogl_color_set_from_4ub (&white, 0xff, 0xff, 0xff, 0xff);
data.prim = cogl_primitive_new_p3t2 (COGL_VERTICES_MODE_TRIANGLES,
G_N_ELEMENTS (vertices),
vertices);
/* Load a jpeg crate texture from a file */
printf ("crate.jpg (CC by-nc-nd http://bit.ly/9kP45T) ShadowRunner27 http://bit.ly/m1YXLh\n");
data.texture = cogl_texture_new_from_file (COGL_EXAMPLES_DATA "crate.jpg",
COGL_TEXTURE_NO_SLICING,
COGL_PIXEL_FORMAT_ANY,
NULL);
if (!data.texture)
g_error ("Failed to load texture");
/* a CoglPipeline conceptually describes all the state for vertex
* processing, fragment processing and blending geometry. When
* drawing the geometry for the crate this pipeline says to sample a
* single texture during fragment processing... */
data.crate_pipeline = cogl_pipeline_new ();
cogl_pipeline_set_layer_texture (data.crate_pipeline, 0, data.texture);
/* Since the box is made of multiple triangles that will overlap
* when drawn and we don't control the order they are drawn in, we
* enable depth testing to make sure that triangles that shouldn't
* be visible get culled by the GPU. */
cogl_depth_state_init (&depth_state);
cogl_depth_state_set_test_enabled (&depth_state, TRUE);
cogl_pipeline_set_depth_state (data.crate_pipeline, &depth_state, NULL);
/* Setup a Pango font map and context */
data.pango_font_map = COGL_PANGO_FONT_MAP (cogl_pango_font_map_new());
cogl_pango_font_map_set_use_mipmapping (data.pango_font_map, TRUE);
data.pango_context = cogl_pango_font_map_create_context (data.pango_font_map);
data.pango_font_desc = pango_font_description_new ();
pango_font_description_set_family (data.pango_font_desc, "Sans");
pango_font_description_set_size (data.pango_font_desc, 30 * PANGO_SCALE);
/* Setup the "Hello Cogl" text */
data.hello_label = pango_layout_new (data.pango_context);
pango_layout_set_font_description (data.hello_label, data.pango_font_desc);
pango_layout_set_text (data.hello_label, "Hello Cogl", -1);
pango_layout_get_extents (data.hello_label, NULL, &hello_label_size);
data.hello_label_width = PANGO_PIXELS (hello_label_size.width);
data.hello_label_height = PANGO_PIXELS (hello_label_size.height);
cogl_push_framebuffer (fb);
while (1)
{
paint (&data);
cogl_framebuffer_swap_buffers (fb);
}
return 0;
}