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/cvs/OpenCL/examples/juliaflight
Revision: 1.5
Committed: Tue Oct 22 17:25:38 2013 UTC (10 years, 11 months ago) by root
Branch: MAIN
CVS Tags: HEAD
Changes since 1.4: +11 -8 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 #!/usr/bin/perl
2
3 use OpenGL ":all";
4 use OpenCL;
5
6 my $S = $ARGV[0] || 256; # window/texture size, smaller is faster
7
8 # open a window and create a gl texture
9 OpenGL::glpOpenWindow width => $S, height => $S;
10 my $texid = glGenTextures_p 1;
11 glBindTexture GL_TEXTURE_2D, $texid;
12 glTexImage2D_c GL_TEXTURE_2D, 0, GL_RGBA8, $S, $S, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0;
13
14 # find and use the first opencl device that let's us get a shared opengl context
15 my $platform;
16 my $dev;
17 my $ctx;
18
19 sub get_context {
20 for (OpenCL::platforms) {
21 $platform = $_;
22 for ($platform->devices) {
23 $dev = $_;
24 $ctx = eval { $platform->context ([OpenCL::GLX_DISPLAY_KHR, undef, OpenCL::GL_CONTEXT_KHR, undef], [$dev]) }
25 and return;
26 }
27 }
28
29 die "cannot find suitable OpenCL device\n";
30 }
31
32 get_context;
33
34 print "using ", $dev->name, "\n";
35
36 my $queue = $ctx->queue ($dev);
37
38 # now attach an opencl image2d object to the opengl texture
39 my $tex = $ctx->gl_texture2d (OpenCL::MEM_WRITE_ONLY, GL_TEXTURE_2D, 0, $texid);
40
41 # now the boring opencl code
42 my $src = <<EOF;
43 kernel void
44 juliatunnel (write_only image2d_t img, float time)
45 {
46 int2 xy = (int2)(get_global_id (0), get_global_id (1));
47 float2 p = convert_float2 (xy) / $S.f * 2.f - 1.f;
48
49 float2 m = (float2)(1.f, p.y) / fabs (p.x); // tunnel
50 m.x = fabs (fmod (m.x + time * 0.05f, 4.f) - 2.f);
51
52 float2 z = m;
53 float2 c = (float2)(sin (time * 0.01133f), cos (time * 0.02521f));
54
55 for (int i = 0; i < 25 && dot (z, z) < 4.f; ++i) // standard julia
56 z = (float2)(z.x * z.x - z.y * z.y, 2.f * z.x * z.y) + c;
57
58 float3 colour = (float3)(z.x, z.y, atan2 (z.y, z.x));
59 write_imagef (img, xy, (float4)(colour * p.x * p.x, 1.));
60 }
61 EOF
62
63 my $prog = $ctx->build_program ($src);
64 my $kernel = $prog->kernel ("juliatunnel");
65
66 # program compiled, kernel ready, now draw and loop
67
68 for (my $time; ; ++$time) {
69 # acquire objects from opengl
70 $queue->acquire_gl_objects ([$tex]);
71
72 # configure and run our kernel
73 $kernel->setf ("mf", $tex, $time*2); # mf = memory object, float
74 $queue->nd_range_kernel ($kernel, undef, [$S, $S], undef);
75
76 # release objects to opengl again
77 $queue->release_gl_objects ([$tex]);
78
79 # wait
80 $queue->finish;
81
82 # now draw the texture, the defaults should be all right
83 glTexParameterf GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST;
84
85 glEnable GL_TEXTURE_2D;
86 glBegin GL_QUADS;
87 glTexCoord2f 0, 1; glVertex3i -1, -1, -1;
88 glTexCoord2f 0, 0; glVertex3i 1, -1, -1;
89 glTexCoord2f 1, 0; glVertex3i 1, 1, -1;
90 glTexCoord2f 1, 1; glVertex3i -1, 1, -1;
91 glEnd;
92
93 glXSwapBuffers;
94
95 select undef, undef, undef, 1/60;
96 }