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