1[require] 2GL >= 3.3 3GLSL >= 3.30 4GL_ARB_shader_storage_buffer_object 5GL_ARB_shader_atomic_counters 6GL_ARB_shader_atomic_counter_ops 7GL_ARB_gpu_shader5 8 9[vertex shader passthrough] 10 11[fragment shader] 12#extension GL_ARB_shader_storage_buffer_object: require 13#extension GL_ARB_shader_atomic_counters: require 14#extension GL_ARB_shader_atomic_counter_ops: require 15#extension GL_ARB_gpu_shader5: require 16 17layout(binding = 0) buffer bufblock { 18 int value; 19}; 20 21/* GL_ARB_shader_atomic_counters requires at least 8 total counters. */ 22layout(binding = 0) uniform atomic_uint mask[7]; 23layout(binding = 0) uniform atomic_uint fail; 24 25out vec4 color; 26 27void main() 28{ 29 /* According to issue #22 of the GL_ARB_shader_image_load_store, the 30 * return result of atomic operations in helper invocations is 31 * undefined. To avoid a possible infinite loop (below) in a helper 32 * invocation, bail out now. 33 */ 34 if (gl_SampleMaskIn[0] == 0) 35 return; 36 37 /* Each of 32 * N fragments should see a unique value. Each value 38 * observed is tracked in "mask." The test automatically fails if a 39 * duplicate value is observed. After the shaders are done running, 40 * the mask values will be probed to ensure that all possible values 41 * were observed. 42 */ 43 int f; 44 45 /* This is an open-coded atomicAdd. */ 46 do { 47 f = value; 48 } while (f != atomicCompSwap(value, f, f + 4)); 49 50 uint i = uint(f) / 4u; 51 uint bit = i % 32u; 52 int c = int(i / 32u); 53 uint m = 1u << bit; 54 55 if (c < mask.length()) { 56 /* If the bit was already set, the test fails. */ 57 if ((atomicCounterOrARB(mask[c], m) & m) != 0u) 58 atomicCounterIncrement(fail); 59 60 color = vec4(0.0, 1.0, 0.0, 1.0); 61 } else { 62 color = vec4(0.0, 0.0, 1.0, 1.0); 63 } 64} 65 66[test] 67atomic counters 8 68 69ssbo 0 32 70ssbo 0 subdata float 0 0.0 71 72clear color 0.5 0.5 0.5 0.5 73clear 74 75draw rect -1 -1 2 2 76 77probe atomic counter 0 == 4294967295 78probe atomic counter 1 == 4294967295 79probe atomic counter 2 == 4294967295 80probe atomic counter 3 == 4294967295 81probe atomic counter 4 == 4294967295 82probe atomic counter 5 == 4294967295 83probe atomic counter 6 == 4294967295 84probe atomic counter 7 == 0 85