eb89c3a428
These are transpiled to kernel functions that write the output of the shader to three buffers: one for per-vertex varyings, one for per-patch varyings, and one for the tessellation levels. This structure is mandated by the way Metal works, where the tessellation factors are supplied to the draw method in their own buffer, while the per-patch and per-vertex varyings are supplied as though they were vertex attributes; since they have different step rates, they must be in separate buffers. The kernel is expected to be run in a workgroup whose size is the greater of the number of input or output control points. It uses Metal's support for vertex-style stage input to a compute shader to get the input values; therefore, at least one instance must run per input point. Meanwhile, Vulkan mandates that it run at least once per output point. Overrunning the output array is a concern, but any values written should either be discarded or overwritten by subsequent patches. I'm probably going to put some slop space in the buffer when I integrate this into MoltenVK to be on the safe side.
133 lines
5.2 KiB
GLSL
133 lines
5.2 KiB
GLSL
#pragma clang diagnostic ignored "-Wmissing-prototypes"
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#include <metal_stdlib>
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#include <simd/simd.h>
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using namespace metal;
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struct UBO
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{
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float4 uScale;
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float3 uCamPos;
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float2 uPatchSize;
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float2 uMaxTessLevel;
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float uDistanceMod;
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float4 uFrustum[6];
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};
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struct main0_patchOut
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{
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float2 vOutPatchPosBase;
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float4 vPatchLods;
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};
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struct main0_in
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{
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float2 vPatchPosBase [[attribute(0)]];
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};
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bool frustum_cull(thread const float2& p0, constant UBO& v_41)
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{
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float2 min_xz = (p0 - float2(10.0)) * v_41.uScale.xy;
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float2 max_xz = ((p0 + v_41.uPatchSize) + float2(10.0)) * v_41.uScale.xy;
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float3 bb_min = float3(min_xz.x, -10.0, min_xz.y);
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float3 bb_max = float3(max_xz.x, 10.0, max_xz.y);
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float3 center = (bb_min + bb_max) * 0.5;
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float radius = 0.5 * length(bb_max - bb_min);
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float3 f0 = float3(dot(v_41.uFrustum[0], float4(center, 1.0)), dot(v_41.uFrustum[1], float4(center, 1.0)), dot(v_41.uFrustum[2], float4(center, 1.0)));
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float3 f1 = float3(dot(v_41.uFrustum[3], float4(center, 1.0)), dot(v_41.uFrustum[4], float4(center, 1.0)), dot(v_41.uFrustum[5], float4(center, 1.0)));
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float3 _199 = f0;
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float _200 = radius;
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bool _205 = any(_199 <= float3(-_200));
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bool _215;
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if (!_205)
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{
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_215 = any(f1 <= float3(-radius));
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}
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else
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{
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_215 = _205;
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}
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return !_215;
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}
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float lod_factor(thread const float2& pos_, constant UBO& v_41)
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{
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float2 pos = pos_ * v_41.uScale.xy;
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float3 dist_to_cam = v_41.uCamPos - float3(pos.x, 0.0, pos.y);
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float level = log2((length(dist_to_cam) + 9.9999997473787516355514526367188e-05) * v_41.uDistanceMod);
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return fast::clamp(level, 0.0, v_41.uMaxTessLevel.x);
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}
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float4 tess_level(thread const float4& lod, constant UBO& v_41)
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{
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return exp2(-lod) * v_41.uMaxTessLevel.y;
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}
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float tess_level(thread const float& lod, constant UBO& v_41)
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{
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return v_41.uMaxTessLevel.y * exp2(-lod);
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}
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void compute_tess_levels(thread const float2& p0, constant UBO& v_41, device float2& vOutPatchPosBase, device float4& vPatchLods, device half (&gl_TessLevelOuter)[4], device half (&gl_TessLevelInner)[2])
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{
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vOutPatchPosBase = p0;
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float2 param = p0 + (float2(-0.5) * v_41.uPatchSize);
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float l00 = lod_factor(param, v_41);
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float2 param_1 = p0 + (float2(0.5, -0.5) * v_41.uPatchSize);
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float l10 = lod_factor(param_1, v_41);
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float2 param_2 = p0 + (float2(1.5, -0.5) * v_41.uPatchSize);
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float l20 = lod_factor(param_2, v_41);
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float2 param_3 = p0 + (float2(-0.5, 0.5) * v_41.uPatchSize);
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float l01 = lod_factor(param_3, v_41);
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float2 param_4 = p0 + (float2(0.5) * v_41.uPatchSize);
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float l11 = lod_factor(param_4, v_41);
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float2 param_5 = p0 + (float2(1.5, 0.5) * v_41.uPatchSize);
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float l21 = lod_factor(param_5, v_41);
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float2 param_6 = p0 + (float2(-0.5, 1.5) * v_41.uPatchSize);
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float l02 = lod_factor(param_6, v_41);
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float2 param_7 = p0 + (float2(0.5, 1.5) * v_41.uPatchSize);
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float l12 = lod_factor(param_7, v_41);
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float2 param_8 = p0 + (float2(1.5) * v_41.uPatchSize);
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float l22 = lod_factor(param_8, v_41);
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float4 lods = float4(dot(float4(l01, l11, l02, l12), float4(0.25)), dot(float4(l00, l10, l01, l11), float4(0.25)), dot(float4(l10, l20, l11, l21), float4(0.25)), dot(float4(l11, l21, l12, l22), float4(0.25)));
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vPatchLods = lods;
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float4 outer_lods = fast::min(lods, lods.yzwx);
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float4 param_9 = outer_lods;
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float4 levels = tess_level(param_9, v_41);
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gl_TessLevelOuter[0] = half(levels.x);
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gl_TessLevelOuter[1] = half(levels.y);
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gl_TessLevelOuter[2] = half(levels.z);
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gl_TessLevelOuter[3] = half(levels.w);
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float min_lod = fast::min(fast::min(lods.x, lods.y), fast::min(lods.z, lods.w));
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float param_10 = fast::min(min_lod, l11);
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float inner = tess_level(param_10, v_41);
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gl_TessLevelInner[0] = half(inner);
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gl_TessLevelInner[1] = half(inner);
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}
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kernel void main0(main0_in in [[stage_in]], constant UBO& v_41 [[buffer(0)]], uint gl_InvocationID [[thread_index_in_threadgroup]], uint gl_PrimitiveID [[threadgroup_position_in_grid]], device uint* spvIndirectParams [[buffer(29)]], device main0_patchOut* spvPatchOut [[buffer(27)]], device MTLQuadTessellationFactorsHalf* spvTessLevel [[buffer(26)]], threadgroup main0_in* gl_in [[threadgroup(0)]])
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{
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device main0_patchOut& patchOut = spvPatchOut[gl_PrimitiveID];
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if (gl_InvocationID < spvIndirectParams[0])
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gl_in[gl_InvocationID] = in;
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threadgroup_barrier(mem_flags::mem_threadgroup);
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float2 p0 = gl_in[0].vPatchPosBase;
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float2 param = p0;
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if (!frustum_cull(param, v_41))
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{
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spvTessLevel[gl_PrimitiveID].edgeTessellationFactor[0] = half(-1.0);
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spvTessLevel[gl_PrimitiveID].edgeTessellationFactor[1] = half(-1.0);
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spvTessLevel[gl_PrimitiveID].edgeTessellationFactor[2] = half(-1.0);
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spvTessLevel[gl_PrimitiveID].edgeTessellationFactor[3] = half(-1.0);
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spvTessLevel[gl_PrimitiveID].insideTessellationFactor[0] = half(-1.0);
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spvTessLevel[gl_PrimitiveID].insideTessellationFactor[1] = half(-1.0);
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}
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else
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{
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float2 param_1 = p0;
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compute_tess_levels(param_1, v_41, patchOut.vOutPatchPosBase, patchOut.vPatchLods, spvTessLevel[gl_PrimitiveID].edgeTessellationFactor, spvTessLevel[gl_PrimitiveID].insideTessellationFactor);
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}
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}
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