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Initial uniform buffers implementation
This commit is contained in:
bloeys
@ -1,23 +1,22 @@
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package buffers
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import (
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"fmt"
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"github.com/bloeys/nmage/assert"
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"github.com/go-gl/gl/v4.1-core/gl"
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)
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//Element represents an element that makes up a buffer (e.g. Vec3 at an offset of 12 bytes)
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// Element represents an element that makes up a buffer (e.g. Vec3 at an offset of 12 bytes)
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type Element struct {
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Offset int
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ElementType
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}
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//ElementType is the type of an element thats makes up a buffer (e.g. Vec3)
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type ElementType int
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// ElementType is the type of an element thats makes up a buffer (e.g. Vec3)
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type ElementType uint8
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const (
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DataTypeUnknown ElementType = iota
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DataTypeUint32
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DataTypeInt32
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DataTypeFloat32
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@ -25,35 +24,48 @@ const (
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DataTypeVec2
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DataTypeVec3
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DataTypeVec4
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DataTypeMat2
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DataTypeMat3
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DataTypeMat4
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)
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func (dt ElementType) GLType() uint32 {
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switch dt {
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case DataTypeUint32:
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return gl.UNSIGNED_INT
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case DataTypeInt32:
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return gl.INT
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case DataTypeFloat32:
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fallthrough
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case DataTypeVec2:
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fallthrough
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case DataTypeVec3:
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fallthrough
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case DataTypeVec4:
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fallthrough
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case DataTypeMat2:
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fallthrough
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case DataTypeMat3:
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fallthrough
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case DataTypeMat4:
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return gl.FLOAT
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default:
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assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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//CompSize returns the size in bytes for one component of the type (e.g. for Vec2 its 4)
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// CompSize returns the size in bytes for one component of the type (e.g. for Vec2 its 4).
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// Bools return 1, although in layout=std140 its 4
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func (dt ElementType) CompSize() int32 {
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switch dt {
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case DataTypeUint32:
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fallthrough
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case DataTypeFloat32:
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@ -65,15 +77,21 @@ func (dt ElementType) CompSize() int32 {
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case DataTypeVec3:
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fallthrough
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case DataTypeVec4:
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fallthrough
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case DataTypeMat2:
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fallthrough
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case DataTypeMat3:
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fallthrough
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case DataTypeMat4:
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return 4
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default:
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assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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//CompCount returns the number of components in the element (e.g. for Vec2 its 2)
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// CompCount returns the number of components in the element (e.g. for Vec2 its 2)
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func (dt ElementType) CompCount() int32 {
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switch dt {
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@ -91,16 +109,24 @@ func (dt ElementType) CompCount() int32 {
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case DataTypeVec4:
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return 4
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case DataTypeMat2:
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return 2 * 2
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case DataTypeMat3:
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return 3 * 3
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case DataTypeMat4:
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return 4 * 4
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default:
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assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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//Size returns the total size in bytes (e.g. for vec3 its 3*4=12 bytes)
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// Size returns the total size in bytes (e.g. for vec3 its 3*4=12 bytes)
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func (dt ElementType) Size() int32 {
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switch dt {
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case DataTypeUint32:
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fallthrough
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case DataTypeFloat32:
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@ -115,8 +141,110 @@ func (dt ElementType) Size() int32 {
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case DataTypeVec4:
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return 4 * 4
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case DataTypeMat2:
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return 2 * 2 * 4
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case DataTypeMat3:
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return 3 * 3 * 4
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case DataTypeMat4:
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return 4 * 4 * 4
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default:
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assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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func (dt ElementType) GlStd140BaseAlignment() uint8 {
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switch dt {
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case DataTypeUint32:
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fallthrough
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case DataTypeFloat32:
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fallthrough
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case DataTypeInt32:
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return 4
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case DataTypeVec2:
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return 4 * 2
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// Vec3 has the same alignment as vec4
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case DataTypeVec3:
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fallthrough
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case DataTypeVec4:
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return 4 * 4
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// Matrices follow: (vec4Alignment) * numColumns
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case DataTypeMat2:
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return (4 * 4) * 2
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case DataTypeMat3:
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return (4 * 4) * 3
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case DataTypeMat4:
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return (4 * 4) * 4
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default:
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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func (dt ElementType) GlStd140AlignmentBoundary() uint16 {
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switch dt {
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case DataTypeUint32:
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fallthrough
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case DataTypeFloat32:
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fallthrough
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case DataTypeInt32:
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return 4
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case DataTypeVec2:
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return 8
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case DataTypeVec3:
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fallthrough
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case DataTypeVec4:
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fallthrough
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case DataTypeMat2:
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fallthrough
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case DataTypeMat3:
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fallthrough
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case DataTypeMat4:
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return 16
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default:
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assert.T(false, "Unknown data type passed. DataType '%d'", dt)
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return 0
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}
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}
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func (dt ElementType) String() string {
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switch dt {
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case DataTypeUint32:
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return "uint32"
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case DataTypeFloat32:
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return "float32"
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case DataTypeInt32:
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return "int32"
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case DataTypeVec2:
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return "Vec2"
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case DataTypeVec3:
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return "Vec3"
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case DataTypeVec4:
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return "Vec4"
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case DataTypeMat2:
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return "Mat2"
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case DataTypeMat3:
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return "Mat3"
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case DataTypeMat4:
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return "Mat4"
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default:
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return "Unknown"
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}
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}
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159
buffers/uniform_buffer.go
Executable file
159
buffers/uniform_buffer.go
Executable file
@ -0,0 +1,159 @@
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package buffers
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import (
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"github.com/bloeys/gglm/gglm"
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"github.com/bloeys/nmage/assert"
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"github.com/bloeys/nmage/logging"
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"github.com/go-gl/gl/v4.1-core/gl"
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)
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type UniformBufferFieldInput struct {
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Id uint16
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Type ElementType
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}
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type UniformBufferField struct {
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Id uint16
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AlignedOffset uint16
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Type ElementType
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}
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type UniformBuffer struct {
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Id uint32
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// Size is the allocated memory in bytes on the GPU for this uniform buffer
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Size uint32
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Fields []UniformBufferField
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}
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func (ub *UniformBuffer) Bind() {
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gl.BindBuffer(gl.UNIFORM_BUFFER, ub.Id)
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}
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func (ub *UniformBuffer) UnBind() {
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gl.BindBuffer(gl.UNIFORM_BUFFER, 0)
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}
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func (ub *UniformBuffer) addFields(fields []UniformBufferFieldInput) (totalSize uint32) {
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if len(fields) == 0 {
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return 0
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}
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var alignedOffset uint16 = 0
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ub.Fields = make([]UniformBufferField, 0, len(fields))
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fieldIdToTypeMap := make(map[uint16]ElementType, len(fields))
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for i := 0; i < len(fields); i++ {
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f := fields[i]
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existingFieldType, ok := fieldIdToTypeMap[f.Id]
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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())
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// To understand this take an example. Say we have a total offset of 100 and we are adding a vec4.
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// Vec4s must be aligned to a 16 byte boundary but 100 is not (100 % 16 != 0).
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//
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// To fix this, we take the alignment error which is alignErr=100 % 16=4, but this is error to the nearest
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// boundary, which is below the offset.
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//
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// To get the nearest boundary larger than the offset we can:
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// offset + (boundary - alignErr) == 100 + (16 - 4) == 112; 112 % 16 == 0, meaning its a boundary
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alignmentBoundary := f.Type.GlStd140AlignmentBoundary()
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alignmentError := alignedOffset % alignmentBoundary
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if alignmentError != 0 {
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alignedOffset += alignmentBoundary - alignmentError
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}
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newField := UniformBufferField{Id: f.Id, Type: f.Type, AlignedOffset: alignedOffset}
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ub.Fields = append(ub.Fields, newField)
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// Prepare aligned offset for the next field
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alignedOffset = newField.AlignedOffset + uint16(f.Type.GlStd140BaseAlignment())
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}
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return uint32(alignedOffset)
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}
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func (ub *UniformBuffer) getField(fieldId uint16, fieldType ElementType) UniformBufferField {
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for i := 0; i < len(ub.Fields); i++ {
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f := ub.Fields[i]
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if f.Id != fieldId {
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continue
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}
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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())
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return f
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}
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logging.ErrLog.Panicf("couldn't find uniform buffer field of id=%d and type=%s\n", fieldId, fieldType.String())
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return UniformBufferField{}
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}
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func (ub *UniformBuffer) SetInt32(fieldId uint16, val int32) {
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f := ub.getField(fieldId, DataTypeInt32)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
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}
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func (ub *UniformBuffer) SetUint32(fieldId uint16, val uint32) {
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f := ub.getField(fieldId, DataTypeUint32)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
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}
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func (ub *UniformBuffer) SetFloat32(fieldId uint16, val float32) {
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f := ub.getField(fieldId, DataTypeFloat32)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4, gl.Ptr(&val))
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}
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func (ub *UniformBuffer) SetVec2(fieldId uint16, val *gglm.Vec2) {
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f := ub.getField(fieldId, DataTypeVec2)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*2, gl.Ptr(&val.Data[0]))
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}
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func (ub *UniformBuffer) SetVec3(fieldId uint16, val *gglm.Vec3) {
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f := ub.getField(fieldId, DataTypeVec3)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*3, gl.Ptr(&val.Data[0]))
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}
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func (ub *UniformBuffer) SetVec4(fieldId uint16, val *gglm.Vec4) {
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f := ub.getField(fieldId, DataTypeVec4)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*4, gl.Ptr(&val.Data[0]))
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}
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func (ub *UniformBuffer) SetMat2(fieldId uint16, val *gglm.Mat2) {
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f := ub.getField(fieldId, DataTypeMat2)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*4, gl.Ptr(&val.Data[0][0]))
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}
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func (ub *UniformBuffer) SetMat3(fieldId uint16, val *gglm.Mat3) {
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f := ub.getField(fieldId, DataTypeMat3)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*9, gl.Ptr(&val.Data[0][0]))
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}
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func (ub *UniformBuffer) SetMat4(fieldId uint16, val *gglm.Mat4) {
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f := ub.getField(fieldId, DataTypeMat4)
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gl.BufferSubData(gl.UNIFORM_BUFFER, int(f.AlignedOffset), 4*16, gl.Ptr(&val.Data[0][0]))
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}
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func NewUniformBuffer(fields []UniformBufferFieldInput) UniformBuffer {
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ub := UniformBuffer{}
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ub.Size = ub.addFields(fields)
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gl.GenBuffers(1, &ub.Id)
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if ub.Id == 0 {
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logging.ErrLog.Panicln("Failed to create OpenGL buffer for a uniform buffer")
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}
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ub.Bind()
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gl.BufferData(gl.UNIFORM_BUFFER, int(ub.Size), gl.Ptr(nil), gl.STATIC_DRAW)
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return ub
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}
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@ -55,7 +55,7 @@ func NewVertexBuffer(layout ...Element) VertexBuffer {
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gl.GenBuffers(1, &vb.Id)
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if vb.Id == 0 {
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logging.ErrLog.Println("Failed to create OpenGL buffer")
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logging.ErrLog.Panicln("Failed to create OpenGL buffer")
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}
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vb.SetLayout(layout...)
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Reference in New Issue
Block a user