08b0d2d63e
The first vertex in the triangle vertices used in the cogl-hello example (which were copied into a few other examples) for some reason has a semi-transparent alpha component. However the colour needs to be pre-multiplied and the red component was still 0xff so the colour is effectively invalid and the transparency isn't shown. This patch just sets the alpha component to 0xff to make it less confusing. Reviewed-by: Robert Bragg <robert@linux.intel.com> (cherry picked from commit 461879986ec012556b4e680b73e36d440927faaa)
80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
#include <cogl/cogl.h>
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#include <glib.h>
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#include <stdio.h>
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typedef struct _Data
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{
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CoglContext *ctx;
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CoglFramebuffer *fb;
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CoglPrimitive *triangle;
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CoglPipeline *pipeline;
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} Data;
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static CoglBool
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paint_cb (void *user_data)
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{
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Data *data = user_data;
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cogl_framebuffer_clear4f (data->fb, COGL_BUFFER_BIT_COLOR, 0, 0, 0, 1);
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cogl_framebuffer_draw_primitive (data->fb, data->pipeline, data->triangle);
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cogl_onscreen_swap_buffers (COGL_ONSCREEN (data->fb));
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return FALSE; /* remove the callback */
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}
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static void
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frame_event_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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if (event == COGL_FRAME_EVENT_SYNC)
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paint_cb (user_data);
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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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Data data;
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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, 0xff},
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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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GSource *cogl_source;
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GMainLoop *loop;
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data.ctx = cogl_context_new (NULL, &error);
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if (!data.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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onscreen = cogl_onscreen_new (data.ctx, 640, 480);
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cogl_onscreen_show (onscreen);
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data.fb = COGL_FRAMEBUFFER (onscreen);
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cogl_onscreen_set_resizable (onscreen, TRUE);
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data.triangle = cogl_primitive_new_p2c4 (data.ctx,
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COGL_VERTICES_MODE_TRIANGLES,
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3, triangle_vertices);
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data.pipeline = cogl_pipeline_new (data.ctx);
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cogl_source = cogl_glib_source_new (data.ctx, G_PRIORITY_DEFAULT);
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g_source_attach (cogl_source, NULL);
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cogl_onscreen_add_frame_callback (COGL_ONSCREEN (data.fb),
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frame_event_cb,
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&data,
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NULL); /* destroy notify */
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g_idle_add (paint_cb, &data);
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loop = g_main_loop_new (NULL, TRUE);
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g_main_loop_run (loop);
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return 0;
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}
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