mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
104 lines
3.7 KiB
Go
104 lines
3.7 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package ofdgo
|
|
|
|
import (
|
|
"fmt"
|
|
"image"
|
|
"math"
|
|
)
|
|
|
|
// viewLayers 按ECMA-363第9.5.4节依次绘制背景层或覆盖层
|
|
// 入参: layers 按后至前排列的纹理层
|
|
// 返回: error 参数、资源、预算或取消错误
|
|
func (r *u3dRender) viewLayers(layers []U3DViewLayer) error {
|
|
for _, layer := range layers {
|
|
if err := r.ctx.Err(); err != nil {
|
|
return err
|
|
}
|
|
for _, value := range [...]float32{layer.Blend, layer.Rotation, layer.Location[0], layer.Location[1], layer.Scale[0], layer.Scale[1]} {
|
|
if !finite(float64(value)) {
|
|
return fmt.Errorf("invalid U3D view layer values")
|
|
}
|
|
}
|
|
texture, err := r.texture(layer.Texture)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
blend := min(1, max(0, float64(layer.Blend)))
|
|
if blend == 0 || layer.Scale[0] == 0 || layer.Scale[1] == 0 {
|
|
continue
|
|
}
|
|
sin, cos := math.Sincos(float64(layer.Rotation))
|
|
x, y := float64(layer.Location[0]), float64(layer.Location[1])
|
|
if r.view.Attributes&1 != 0 {
|
|
x *= float64(r.output.Rect.Dx())
|
|
y *= float64(r.output.Rect.Dy())
|
|
}
|
|
sx, sy := float64(layer.Scale[0]), float64(layer.Scale[1])
|
|
rx, ry := float64(layer.Registration[0]), float64(layer.Registration[1])
|
|
m := RasterMatrix{cos * sx, -sin * sx, sin * sy, cos * sy, x - cos*sx*rx - sin*sy*ry, y + sin*sx*rx - cos*sy*ry}
|
|
bounds := rasterImageBounds(texture.Bounds(), m, r.output.Bounds())
|
|
for py := bounds.Min.Y; py < bounds.Max.Y; py++ {
|
|
for px := bounds.Min.X; px < bounds.Max.X; px++ {
|
|
if px%4096 == 0 || px == bounds.Min.X {
|
|
if err := r.ctx.Err(); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
cx, cy := float64(px)+.5, float64(py)+.5
|
|
if cx < r.viewport[0] || cy < r.viewport[1] || cx >= r.viewport[0]+r.viewport[2] || cy >= r.viewport[1]+r.viewport[3] {
|
|
continue
|
|
}
|
|
dx, dy := cx-x, cy-y
|
|
u, v := (cos*dx-sin*dy)/sx+rx, (sin*dx+cos*dy)/sy+ry
|
|
if u < 0 || v < 0 || u >= float64(texture.Rect.Dx()) || v >= float64(texture.Rect.Dy()) {
|
|
continue
|
|
}
|
|
value := u3dTextureSample(texture, u, v)
|
|
pixel := &r.frame[py*r.output.Rect.Dx()+px]
|
|
alpha := value[3] * blend
|
|
for i := range pixel.color {
|
|
pixel.color[i] = value[i]*blend + pixel.color[i]*(1-alpha)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return r.ctx.Err()
|
|
}
|
|
|
|
// u3dTextureSample 在像素中心进行双线性采样，使用预乘颜色避免透明边缘色晕
|
|
// 入参: texture 纹理, x 横向像素坐标, y 纵向像素坐标
|
|
// 返回: [4]float64 预乘颜色及透明度
|
|
func u3dTextureSample(texture *image.NRGBA64, x, y float64) [4]float64 {
|
|
x, y = x-.5, y-.5
|
|
x0, y0 := int(math.Floor(x)), int(math.Floor(y))
|
|
fx, fy := x-float64(x0), y-float64(y0)
|
|
wx, wy := [2]float64{1 - fx, fx}, [2]float64{1 - fy, fy}
|
|
var result [4]float64
|
|
for row := range 2 {
|
|
for col := range 2 {
|
|
weight := wx[col] * wy[row]
|
|
c := texture.NRGBA64At(min(max(0, x0+col), texture.Rect.Max.X-1), min(max(0, y0+row), texture.Rect.Max.Y-1))
|
|
alpha := float64(c.A) / 65535
|
|
result[0] += float64(c.R) / 65535 * alpha * weight
|
|
result[1] += float64(c.G) / 65535 * alpha * weight
|
|
result[2] += float64(c.B) / 65535 * alpha * weight
|
|
result[3] += alpha * weight
|
|
}
|
|
}
|
|
return result
|
|
}
|