Files
nmage/buffers/uniform_buffer.go
2024-05-26 15:03:00 +04:00

448 lines
13 KiB
Go
Executable File

package buffers
import (
"math"
"reflect"
"github.com/bloeys/gglm/gglm"
"github.com/bloeys/nmage/assert"
"github.com/bloeys/nmage/logging"
"github.com/go-gl/gl/v4.1-core/gl"
)
type UniformBufferFieldInput struct {
Id uint16
Type ElementType
// Count should be set in case this field is an array of type `[Count]Type`.
// Count=0 is valid and is equivalent to Count=1, which means the type is NOT an array, but a single field.
Count uint16
}
type UniformBufferField struct {
Id uint16
AlignedOffset uint16
// Count should be set in case this field is an array of type `[Count]Type`.
// Count=0 is valid and is equivalent to Count=1, which means the type is NOT an array, but a single field.
Count uint16
Type ElementType
}
type UniformBuffer struct {
Id uint32
// Size is the allocated memory in bytes on the GPU for this uniform buffer
Size uint32
Fields []UniformBufferField
}
func (ub *UniformBuffer) Bind() {
gl.BindBuffer(gl.UNIFORM_BUFFER, ub.Id)
}
func (ub *UniformBuffer) UnBind() {
gl.BindBuffer(gl.UNIFORM_BUFFER, 0)
}
func (ub *UniformBuffer) addFields(fields []UniformBufferFieldInput) (totalSize uint32) {
if len(fields) == 0 {
return 0
}
var alignedOffset uint16 = 0
ub.Fields = make([]UniformBufferField, 0, len(fields))
fieldIdToTypeMap := make(map[uint16]ElementType, len(fields))
for i := 0; i < len(fields); i++ {
f := fields[i]
if f.Count == 0 {
f.Count = 1
}
existingFieldType, ok := fieldIdToTypeMap[f.Id]
assert.T(!ok, "Uniform buffer field id is reused within the same uniform buffer. FieldId=%d was first used on a field with type=%s and then used on a different field with type=%s\n", f.Id, existingFieldType.String(), f.Type.String())
// To understand this take an example. Say we have a total offset of 100 and we are adding a vec4.
// Vec4s must be aligned to a 16 byte boundary but 100 is not (100 % 16 != 0).
//
// To fix this, we take the alignment error which is alignErr=100 % 16=4, but this is error to the nearest
// boundary, which is below the offset.
//
// To get the nearest boundary larger than the offset we can:
// offset + (boundary - alignErr) == 100 + (16 - 4) == 112; 112 % 16 == 0, meaning its a boundary
//
// Note that arrays of scalars/vectors are always aligned to 16 bytes, like a vec4
var alignmentBoundary uint16 = 16
if f.Count == 1 {
alignmentBoundary = f.Type.GlStd140AlignmentBoundary()
}
alignmentError := alignedOffset % alignmentBoundary
if alignmentError != 0 {
alignedOffset += alignmentBoundary - alignmentError
}
newField := UniformBufferField{Id: f.Id, Type: f.Type, AlignedOffset: alignedOffset, Count: f.Count}
ub.Fields = append(ub.Fields, newField)
// Prepare aligned offset for the next field
alignedOffset = newField.AlignedOffset + alignmentBoundary*f.Count
}
return uint32(alignedOffset)
}
func (ub *UniformBuffer) getField(fieldId uint16, fieldType ElementType) UniformBufferField {
for i := 0; i < len(ub.Fields); i++ {
f := ub.Fields[i]
if f.Id != fieldId {
continue
}
assert.T(f.Type == fieldType, "Uniform buffer field id is reused within the same uniform buffer. FieldId=%d was first used on a field with type=%v, but is now being used on a field with type=%v\n", fieldId, f.Type.String(), fieldType.String())
return f
}
logging.ErrLog.Panicf("couldn't find uniform buffer field of id=%d and type=%s\n", fieldId, fieldType.String())
return UniformBufferField{}
}
func (ub *UniformBuffer) SetInt32(fieldId uint16, val int32) {
f := ub.getField(fieldId, DataTypeInt32)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
}
func (ub *UniformBuffer) SetUint32(fieldId uint16, val uint32) {
f := ub.getField(fieldId, DataTypeUint32)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
}
func (ub *UniformBuffer) SetFloat32(fieldId uint16, val float32) {
f := ub.getField(fieldId, DataTypeFloat32)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
}
func (ub *UniformBuffer) SetVec2(fieldId uint16, val *gglm.Vec2) {
f := ub.getField(fieldId, DataTypeVec2)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*2, gl.Ptr(&val.Data[0]))
}
func (ub *UniformBuffer) SetVec3(fieldId uint16, val *gglm.Vec3) {
f := ub.getField(fieldId, DataTypeVec3)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*3, gl.Ptr(&val.Data[0]))
}
func (ub *UniformBuffer) SetVec4(fieldId uint16, val *gglm.Vec4) {
f := ub.getField(fieldId, DataTypeVec4)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*4, gl.Ptr(&val.Data[0]))
}
func (ub *UniformBuffer) SetMat2(fieldId uint16, val *gglm.Mat2) {
f := ub.getField(fieldId, DataTypeMat2)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*4, gl.Ptr(&val.Data[0][0]))
}
func (ub *UniformBuffer) SetMat3(fieldId uint16, val *gglm.Mat3) {
f := ub.getField(fieldId, DataTypeMat3)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*9, gl.Ptr(&val.Data[0][0]))
}
func (ub *UniformBuffer) SetMat4(fieldId uint16, val *gglm.Mat4) {
f := ub.getField(fieldId, DataTypeMat4)
gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*16, gl.Ptr(&val.Data[0][0]))
}
func (ub *UniformBuffer) SetStruct(inputStruct any) {
if inputStruct == nil {
logging.ErrLog.Panicf("UniformBuffer.SetStruct called with a value that is nil")
}
structVal := reflect.ValueOf(inputStruct)
if structVal.Kind() != reflect.Struct {
logging.ErrLog.Panicf("UniformBuffer.SetStruct called with a value that is not a struct. Val=%v\n", inputStruct)
}
if structVal.NumField() != len(ub.Fields) {
logging.ErrLog.Panicf("struct fields must match uniform buffer fields, but uniform buffer contains %d fields, while the passed struct has %d fields\n", len(ub.Fields), structVal.NumField())
}
writeIndex := 0
buf := make([]byte, ub.Size)
for i := 0; i < len(ub.Fields); i++ {
ubField := &ub.Fields[i]
valField := structVal.Field(i)
kind := valField.Kind()
if kind == reflect.Pointer {
valField = valField.Elem()
}
var elementType reflect.Type
isArray := kind == reflect.Slice || kind == reflect.Array
if isArray {
elementType = valField.Type().Elem()
} else {
elementType = valField.Type()
}
if isArray {
assert.T(valField.Len() == int(ubField.Count), "ubo field of id=%d is an array/slice field of length=%d but got input of length=%d\n", ubField.Id, ubField.Count, valField.Len())
}
typeMatches := false
writeIndex = int(ubField.AlignedOffset)
switch ubField.Type {
case DataTypeUint32:
typeMatches = elementType.Name() == "uint32"
if typeMatches {
if isArray {
Write32BitIntegerSliceToByteBufWithAlignment(buf, &writeIndex, 16, valField.Slice(0, valField.Len()).Interface().([]uint32))
} else {
Write32BitIntegerToByteBuf(buf, &writeIndex, uint32(valField.Uint()))
}
}
case DataTypeFloat32:
typeMatches = elementType.Name() == "float32"
if typeMatches {
if isArray {
WriteF32SliceToByteBufWithAlignment(buf, &writeIndex, 16, valField.Slice(0, valField.Len()).Interface().([]float32))
} else {
WriteF32ToByteBuf(buf, &writeIndex, float32(valField.Float()))
}
}
case DataTypeInt32:
typeMatches = elementType.Name() == "int32"
if typeMatches {
if isArray {
Write32BitIntegerSliceToByteBufWithAlignment(buf, &writeIndex, 16, valField.Slice(0, valField.Len()).Interface().([]int32))
} else {
Write32BitIntegerToByteBuf(buf, &writeIndex, uint32(valField.Int()))
}
}
case DataTypeVec2:
v2, ok := valField.Interface().(gglm.Vec2)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, v2.Data[:])
}
case DataTypeVec3:
v3, ok := valField.Interface().(gglm.Vec3)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, v3.Data[:])
}
case DataTypeVec4:
v4, ok := valField.Interface().(gglm.Vec4)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, v4.Data[:])
}
case DataTypeMat2:
m2, ok := valField.Interface().(gglm.Mat2)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, m2.Data[0][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m2.Data[1][:])
}
case DataTypeMat3:
m3, ok := valField.Interface().(gglm.Mat3)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, m3.Data[0][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m3.Data[1][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m3.Data[2][:])
}
case DataTypeMat4:
m4, ok := valField.Interface().(gglm.Mat4)
typeMatches = ok
if typeMatches {
WriteF32SliceToByteBuf(buf, &writeIndex, m4.Data[0][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m4.Data[1][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m4.Data[2][:])
WriteF32SliceToByteBuf(buf, &writeIndex, m4.Data[3][:])
}
default:
assert.T(false, "Unknown uniform buffer data type passed. DataType '%d'", ubField.Type)
}
if !typeMatches {
logging.ErrLog.Panicf("Struct field ordering and types must match uniform buffer fields, but at field index %d got UniformBufferField=%v but a struct field of %s\n", i, ubField, valField.String())
}
}
if writeIndex == 0 {
return
}
gl.BufferSubData(gl.UNIFORM_BUFFER, 0, writeIndex, gl.Ptr(&buf[0]))
}
func Write32BitIntegerToByteBuf[T uint32 | int32](buf []byte, startIndex *int, val T) {
assert.T(*startIndex+4 <= len(buf), "failed to write uint32/int32 to buffer because the buffer doesn't have enough space. Start index=%d, Buffer length=%d", *startIndex, len(buf))
buf[*startIndex] = byte(val)
buf[*startIndex+1] = byte(val >> 8)
buf[*startIndex+2] = byte(val >> 16)
buf[*startIndex+3] = byte(val >> 24)
*startIndex += 4
}
func Write32BitIntegerSliceToByteBufWithAlignment[T uint32 | int32](buf []byte, startIndex *int, alignmentPerField int, vals []T) {
assert.T(*startIndex+len(vals)*alignmentPerField <= len(buf), "failed to write uint32/int32 with custom alignment=%d to buffer because the buffer doesn't have enough space. Start index=%d, Buffer length=%d, but needs %d bytes free", alignmentPerField, *startIndex, len(buf), len(vals)*alignmentPerField)
for i := 0; i < len(vals); i++ {
val := vals[i]
buf[*startIndex] = byte(val)
buf[*startIndex+1] = byte(val >> 8)
buf[*startIndex+2] = byte(val >> 16)
buf[*startIndex+3] = byte(val >> 24)
*startIndex += alignmentPerField
}
}
func WriteF32ToByteBuf(buf []byte, startIndex *int, val float32) {
assert.T(*startIndex+4 <= len(buf), "failed to write float32 to buffer because the buffer doesn't have enough space. Start index=%d, Buffer length=%d", *startIndex, len(buf))
bits := math.Float32bits(val)
buf[*startIndex] = byte(bits)
buf[*startIndex+1] = byte(bits >> 8)
buf[*startIndex+2] = byte(bits >> 16)
buf[*startIndex+3] = byte(bits >> 24)
*startIndex += 4
}
func WriteF32SliceToByteBuf(buf []byte, startIndex *int, vals []float32) {
assert.T(*startIndex+len(vals)*4 <= len(buf), "failed to write slice of float32 to buffer because the buffer doesn't have enough space. Start index=%d, Buffer length=%d, but needs %d bytes free", *startIndex, len(buf), len(vals)*4)
for i := 0; i < len(vals); i++ {
bits := math.Float32bits(vals[i])
buf[*startIndex] = byte(bits)
buf[*startIndex+1] = byte(bits >> 8)
buf[*startIndex+2] = byte(bits >> 16)
buf[*startIndex+3] = byte(bits >> 24)
*startIndex += 4
}
}
func WriteF32SliceToByteBufWithAlignment(buf []byte, startIndex *int, alignmentPerField int, vals []float32) {
assert.T(*startIndex+len(vals)*alignmentPerField <= len(buf), "failed to write slice of float32 with custom alignment=%d to buffer because the buffer doesn't have enough space. Start index=%d, Buffer length=%d, but needs %d bytes free", alignmentPerField, *startIndex, len(buf), len(vals)*alignmentPerField)
for i := 0; i < len(vals); i++ {
bits := math.Float32bits(vals[i])
buf[*startIndex] = byte(bits)
buf[*startIndex+1] = byte(bits >> 8)
buf[*startIndex+2] = byte(bits >> 16)
buf[*startIndex+3] = byte(bits >> 24)
*startIndex += alignmentPerField
}
}
func ReflectValueMatchesUniformBufferField(v reflect.Value, ubField *UniformBufferField) bool {
if v.Kind() == reflect.Pointer {
v = v.Elem()
}
switch ubField.Type {
case DataTypeUint32:
t := v.Type()
return t.Name() == "uint32"
case DataTypeFloat32:
t := v.Type()
return t.Name() == "float32"
case DataTypeInt32:
t := v.Type()
return t.Name() == "int32"
case DataTypeVec2:
_, ok := v.Interface().(gglm.Vec2)
return ok
case DataTypeVec3:
_, ok := v.Interface().(gglm.Vec3)
return ok
case DataTypeVec4:
_, ok := v.Interface().(gglm.Vec4)
return ok
case DataTypeMat2:
_, ok := v.Interface().(gglm.Mat2)
return ok
case DataTypeMat3:
_, ok := v.Interface().(gglm.Mat3)
return ok
case DataTypeMat4:
_, ok := v.Interface().(gglm.Mat4)
return ok
default:
assert.T(false, "Unknown uniform buffer data type passed. DataType '%d'", ubField.Type)
return false
}
}
func NewUniformBuffer(fields []UniformBufferFieldInput) UniformBuffer {
ub := UniformBuffer{}
ub.Size = ub.addFields(fields)
gl.GenBuffers(1, &ub.Id)
if ub.Id == 0 {
logging.ErrLog.Panicln("Failed to create OpenGL buffer for a uniform buffer")
}
ub.Bind()
gl.BufferData(gl.UNIFORM_BUFFER, int(ub.Size), gl.Ptr(nil), gl.STATIC_DRAW)
return ub
}