EEVEE: Ambient Occlusion: Add sample parameter support for the AO node

The actual sample count is rounded up to a multiple of 4 because we
sample 4 horizons directions.

Changing this setting forces the shader to recompile (because using a
GPU_constant).

2 files changed, 10 insertions, 2 deletions

diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_ambient_occlusion.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_ambient_occlusion.glsl
index 0231aeca04b..edf2c93c9a0 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_ambient_occlusion.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_ambient_occlusion.glsl
@@ -3,12 +3,13 @@ void node_ambient_occlusion(vec4 color,
                             float dist,
                             vec3 normal,
                             const float inverted,
+                            const float sample_count,
                             out vec4 result_color,
                             out float result_ao)
 {
   vec3 bent_normal;
   vec4 rand = texelfetch_noise_tex(gl_FragCoord.xy);
-  OcclusionData data = occlusion_search(viewPosition, maxzBuffer, dist, inverted, 8.0);
+  OcclusionData data = occlusion_search(viewPosition, maxzBuffer, dist, inverted, sample_count);
 
   vec3 V = cameraVec(worldPosition);
   vec3 N = normalize(normal);
diff --git a/source/blender/nodes/shader/nodes/node_shader_ambient_occlusion.c b/source/blender/nodes/shader/nodes/node_shader_ambient_occlusion.c
index 36971d4e799..abe80ebcefb 100644
--- a/source/blender/nodes/shader/nodes/node_shader_ambient_occlusion.c
+++ b/source/blender/nodes/shader/nodes/node_shader_ambient_occlusion.c
@@ -47,8 +47,15 @@ static int node_shader_gpu_ambient_occlusion(GPUMaterial *mat,
   GPU_material_flag_set(mat, GPU_MATFLAG_DIFFUSE);
 
   float inverted = node->custom2 ? 1.0f : 0.0f;
+  float f_samples = divide_ceil_u(node->custom1, 4);
 
-  return GPU_stack_link(mat, node, "node_ambient_occlusion", in, out, GPU_constant(&inverted));
+  return GPU_stack_link(mat,
+                        node,
+                        "node_ambient_occlusion",
+                        in,
+                        out,
+                        GPU_constant(&inverted),
+                        GPU_constant(&f_samples));
 }
 
 static void node_shader_init_ambient_occlusion(bNodeTree *UNUSED(ntree), bNode *node)