when rotation shape changed in metal - swift

Question

I just created a rectangle using four vertices in metal. I just need to rotate it. So I use a model metrics.Here is my vertex shader.
vertex VertexOutTexture vertex_shader_texture(const VertexInTexture vertices [[stage_in]],
constant ModelConstant &modelConstants[[buffer(1)]],
VertexOutTexture v;
v.position = modelConstants.modelMatrix*float4(vertices.position,1);
v.color = vertices.color;
v.textureCoordinates = vertices.textureCoordinates;
return v;
}
it rotate. But shape is changed. So I used projection transformation which converts the node’s coordinates from camera coordinates to normalized coordinates.
I create projrction matrix:
var sceneConstants = ScenceConstants()
set its value:
sceneConstants.projectionMatrix = matrix_float4x4(prespectiveDegreesFov:45, aspectRatio:Float(1.0),nearZ:0.1,farZ:100)
where init mathod is in math.h
init(prespectiveDegreesFov degreesFov:Float, aspectRatio:Float,nearZ:Float,farZ:Float){
let fov = radians(fromDegrees: degreesFov)
let y = 1/tan(fov*0.5)
let x = y/aspectRatio
let z1 = farZ/(nearZ - farZ)
let w = (z1*nearZ)
columns = (
float4(x, 0, 0, 0),
float4(0, y, 0, 0),
float4(0, 0, z1,-1),
float4(0, 0, w, 0)
)
}
send commands to GPU:
commandEncoder.setVertexBytes(&sceneConstants, length: MemoryLayout<ScenceConstants>.stride, index: 2)
change my vertex shader:
v.position = sceneConstants.projectionMatrix* modelConstants.modelMatrix*float4(vertices.position ,1 );
But it did not work.
before rotation:
after rotation:
I have atached math functions I am using below.
func radians(fromDegrees degrees:Float) ->Float{
return (degrees/100)*Float(Double.pi)
}
extension matrix_float4x4 {
init(prespectiveDegreesFov degreesFov:Float, aspectRatio:Float,nearZ:Float,farZ:Float){
let fov = radians(fromDegrees: degreesFov)
let y = 1/tan(fov*0.5)
let x = y/aspectRatio
let z1 = farZ/(nearZ - farZ)
let w = (z1*nearZ)
columns = (
float4(x, 0, 0, 0),
float4(0, y, 0, 0),
float4(0, 0, z1,-1),
float4(0, 0, w, 0)
)
}
mutating func scale(axis: float3){
var result = matrix_identity_float4x4
let x :Float = axis.x
let y :Float = axis.y
let z :Float = axis.z
result.columns = (
float4(x,0,0,0),
float4(0,y,0,0),
float4(0,0,z,0),
float4(0,0,0,1)
)
print("self:\(self)")
self = matrix_multiply(self, result)
}
mutating func translate(direction: float3){
var result = matrix_identity_float4x4
let x :Float = direction.x
let y :Float = direction.y
let z :Float = direction.z
result.columns = (
float4(1,0,0,0),
float4(0,1,0,0),
float4(0,0,1,0),
float4(x,y,z,1)
)
print("self:\(self)")
self = matrix_multiply(self, result)
}
mutating func rotate(angle: Float ,axis: float3){
var result = matrix_identity_float4x4
let x :Float = axis.x
let y :Float = axis.y
let z :Float = axis.z
let c: Float = cos(angle)
let s:Float = sin(angle)
let mc :Float = (1 - c)
let r1c1: Float = x * x * mc + c
let r2c1: Float = x * y * mc + z * s
let r3c1: Float = x * z * mc - y * s
let r4c1: Float = 0.0
let r1c2: Float = y * x * mc - z * s
let r2c2: Float = y * y * mc + c
let r3c2: Float = y * z * mc + x * s
let r4c2: Float = 0.0
let r1c3: Float = z * x * mc + y * s
let r2c3: Float = z * y * mc - x * s
let r3c3: Float = z * z * mc + c
let r4c3: Float = 0.0
let r1c4: Float = 0.0
let r2c4: Float = 0.0
let r3c4: Float = 0.0
let r4c4: Float = 1.0
result.columns = (
float4(r1c1,r2c1,r3c1,r4c1),
float4(r1c2,r2c2,r3c2,r4c2),
float4(r1c3,r2c3,r3c3,r4c3),
float4(r1c4,r2c4,r3c4,r4c4)
)
print("Result:\(result)")
self = matrix_multiply(self, result)
}
}
How can I fix this issue?Any suggestions please?