2 #extension GL_ARB_compute_shader : enable
3 #extension GL_ARB_shader_image_load_store : enable
5 layout(local_size_x=2, local_size_y=16) in;
6 layout(r16) uniform restrict readonly image2D in_y;
7 uniform sampler2D in_cbcr; // Of type RG16.
8 layout(rgb10_a2) uniform restrict writeonly image2D outbuf;
9 uniform float inv_width, inv_height;
13 int xb = int(gl_GlobalInvocationID.x); // X block number.
14 int y = int(gl_GlobalInvocationID.y); // Y (actual line).
15 float yf = (gl_GlobalInvocationID.y + 0.5f) * inv_height; // Y float coordinate.
17 // Load and scale CbCr values, sampling in-between the texels to get
18 // to (left/4 + center/2 + right/4).
20 for (int i = 0; i < 3; ++i) {
21 vec2 a = texture(in_cbcr, vec2((xb * 6 + i * 2) * inv_width, yf)).xy;
22 vec2 b = texture(in_cbcr, vec2((xb * 6 + i * 2 + 1) * inv_width, yf)).xy;
23 pix_cbcr[i] = (a + b) * (0.5 * 65535.0 / 1023.0);
26 // Load and scale the Y values. Note that we use integer coordinates here,
27 // so we don't need to offset by 0.5.
29 for (int i = 0; i < 6; ++i) {
30 pix_y[i] = imageLoad(in_y, ivec2(xb * 6 + i, y)).x * (65535.0 / 1023.0);
33 imageStore(outbuf, ivec2(xb * 4 + 0, y), vec4(pix_cbcr[0].x, pix_y[0], pix_cbcr[0].y, 1.0));
34 imageStore(outbuf, ivec2(xb * 4 + 1, y), vec4(pix_y[1], pix_cbcr[1].x, pix_y[2], 1.0));
35 imageStore(outbuf, ivec2(xb * 4 + 2, y), vec4(pix_cbcr[1].y, pix_y[3], pix_cbcr[2].x, 1.0));
36 imageStore(outbuf, ivec2(xb * 4 + 3, y), vec4(pix_y[4], pix_cbcr[2].y, pix_y[5], 1.0));