4efd82a3b6
The two SDL examples now throttle their rendering to the COGL_FRAME_EVENT_SYNC event. Previously the examples would redraw whenever a mouse motion event is received but now they additionally wait for the sync event which means that if another mouse event comes immediately after rendering the last frame it theoretically could avoid blocking waiting for the last frame to complete. In practice however the SDL winsys doesn't support swap events so it will get the sync event immediately anyway, but it's nice to have the code as an example and a test. This patch also changes the mainloop a bit to do the equivalent steps without the outer main loop which I think makes it a bit easier to follow. Reviewed-by: Robert Bragg <robert@linux.intel.com> (cherry picked from commit 97cdd832dded2ebfaa42ee4bc43319cb8648d01b)
146 lines
3.3 KiB
C
146 lines
3.3 KiB
C
#include <cogl/cogl.h>
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#include <stdio.h>
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#include <SDL.h>
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/* This short example is just to demonstrate mixing SDL with Cogl as a
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simple way to get portable support for events */
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typedef struct Data
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{
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CoglPrimitive *triangle;
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CoglPipeline *pipeline;
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float center_x, center_y;
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CoglFramebuffer *fb;
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CoglBool quit;
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CoglBool redraw_queued;
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CoglBool ready_to_draw;
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} Data;
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static void
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redraw (Data *data)
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{
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CoglFramebuffer *fb = data->fb;
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cogl_framebuffer_clear4f (fb, COGL_BUFFER_BIT_COLOR, 0, 0, 0, 1);
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cogl_framebuffer_push_matrix (fb);
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cogl_framebuffer_translate (fb, data->center_x, -data->center_y, 0.0f);
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cogl_framebuffer_draw_primitive (fb, data->pipeline, data->triangle);
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cogl_framebuffer_pop_matrix (fb);
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cogl_onscreen_swap_buffers (COGL_ONSCREEN (fb));
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}
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static void
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handle_event (Data *data, SDL_Event *event)
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{
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switch (event->type)
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{
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case SDL_VIDEOEXPOSE:
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data->redraw_queued = TRUE;
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break;
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case SDL_MOUSEMOTION:
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{
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int width =
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cogl_framebuffer_get_width (COGL_FRAMEBUFFER (data->fb));
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int height =
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cogl_framebuffer_get_height (COGL_FRAMEBUFFER (data->fb));
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data->center_x = event->motion.x * 2.0f / width - 1.0f;
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data->center_y = event->motion.y * 2.0f / height - 1.0f;
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data->redraw_queued = TRUE;
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}
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break;
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case SDL_QUIT:
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data->quit = TRUE;
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break;
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}
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}
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static void
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frame_cb (CoglOnscreen *onscreen,
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CoglFrameEvent event,
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CoglFrameInfo *info,
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void *user_data)
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{
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Data *data = user_data;
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if (event == COGL_FRAME_EVENT_SYNC)
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data->ready_to_draw = TRUE;
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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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CoglError *error = NULL;
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CoglVertexP2C4 triangle_vertices[] = {
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{0, 0.7, 0xff, 0x00, 0x00, 0x80},
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{-0.7, -0.7, 0x00, 0xff, 0x00, 0xff},
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{0.7, -0.7, 0x00, 0x00, 0xff, 0xff}
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};
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Data data;
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SDL_Event event;
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ctx = cogl_sdl_context_new (SDL_USEREVENT, &error);
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if (!ctx)
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{
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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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onscreen = cogl_onscreen_new (ctx, 800, 600);
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data.fb = COGL_FRAMEBUFFER (onscreen);
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cogl_onscreen_add_frame_callback (onscreen,
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frame_cb,
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&data,
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NULL /* destroy callback */);
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data.center_x = 0.0f;
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data.center_y = 0.0f;
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data.quit = FALSE;
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cogl_onscreen_show (onscreen);
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data.triangle = cogl_primitive_new_p2c4 (ctx, COGL_VERTICES_MODE_TRIANGLES,
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3, triangle_vertices);
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data.pipeline = cogl_pipeline_new (ctx);
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data.redraw_queued = TRUE;
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data.ready_to_draw = TRUE;
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while (!data.quit)
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{
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if (!SDL_PollEvent (&event))
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{
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if (data.redraw_queued && data.ready_to_draw)
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{
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redraw (&data);
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data.redraw_queued = FALSE;
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data.ready_to_draw = FALSE;
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continue;
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}
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cogl_sdl_idle (ctx);
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if (!SDL_WaitEvent (&event))
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{
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fprintf (stderr, "Error waiting for SDL events");
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return 1;
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}
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}
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handle_event (&data, &event);
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cogl_sdl_handle_event (ctx, &event);
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}
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cogl_object_unref (ctx);
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return 0;
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}
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