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81bb5044ea
Unfortunately, the memory layout was not so universal. For example, the memory layout for mat2 is different between Metal and DirectX.
108 lines
3.5 KiB
Go
108 lines
3.5 KiB
Go
// Copyright 2022 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package hlsl
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import (
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"fmt"
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"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
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)
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const UniformVariableBoundaryInDWords = 4
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// UniformVariableOffsetsInDWords returns the offsets of the uniform variables in DWROD units in the HLSL layout.
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func UniformVariableOffsetsInDWords(program *shaderir.Program) []int {
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// https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-packing-rules
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// https://github.com/microsoft/DirectXShaderCompiler/wiki/Buffer-Packing
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align := func(x int) int {
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if x == 0 {
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return 0
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}
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return ((x-1)/UniformVariableBoundaryInDWords + 1) * UniformVariableBoundaryInDWords
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}
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var offsetsInDWords []int
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var headInDWords int
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// TODO: Reorder the variables with packoffset.
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// See https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-variable-packoffset
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for _, u := range program.Uniforms {
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switch u.Main {
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case shaderir.Float:
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 1
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case shaderir.Int:
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 1
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case shaderir.Vec2, shaderir.IVec2:
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if headInDWords%UniformVariableBoundaryInDWords >= 3 {
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headInDWords = align(headInDWords)
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}
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 2
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case shaderir.Vec3, shaderir.IVec3:
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if headInDWords%UniformVariableBoundaryInDWords >= 2 {
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headInDWords = align(headInDWords)
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}
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 3
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case shaderir.Vec4, shaderir.IVec4:
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if headInDWords%UniformVariableBoundaryInDWords >= 1 {
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headInDWords = align(headInDWords)
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}
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 4
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case shaderir.Mat2:
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// For matrices, each column is aligned to the boundary.
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headInDWords = align(headInDWords)
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 6
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case shaderir.Mat3:
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headInDWords = align(headInDWords)
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 11
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case shaderir.Mat4:
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headInDWords = align(headInDWords)
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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headInDWords += 16
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case shaderir.Array:
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// Each array is 16-byte aligned.
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// TODO: What if the array has 2 or more dimensions?
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headInDWords = align(headInDWords)
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offsetsInDWords = append(offsetsInDWords, headInDWords)
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n := u.Sub[0].Uint32Count()
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switch u.Sub[0].Main {
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case shaderir.Mat2:
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n = 6
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case shaderir.Mat3:
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n = 11
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case shaderir.Mat4:
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n = 16
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}
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headInDWords += (u.Length - 1) * align(n)
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// The last element is not with a padding.
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headInDWords += n
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case shaderir.Struct:
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// TODO: Implement this
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panic("hlsl: offset for a struct is not implemented yet")
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default:
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panic(fmt.Sprintf("hlsl: unexpected type: %s", u.String()))
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}
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}
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return offsetsInDWords
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}
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