在学习 Shader 的过程中做的小案例，在 Creator v3.8.3 复现2D物体的翻转效果 或者 叫伪3D效果？
fake3DMaterial.mtl 、 fake3DEffect.effect 用于实现效果
创建 SpriteNode 节点， 给其添加上图和 fake3DMaterial.mtl 材质。
原理
使用旋转矩阵，在片段着色器中对uv进行翻转变化，在顶点着色器对修改后的图像尺寸进行调整。
Effect
通过修改内置的 builtin-sprite.effect 来实现。
参数 properties
properties:
...
FOV: { value: 90, editor: { tooltip: '视场角', range: [1, 179]}}
y_rot: { value: 0, editor: { tooltip: 'y轴角度', range: [-360, 360] }}
x_rot: { value: 0, editor: { tooltip: 'x轴角度', range: [-360, 360] }}
textureSize: { value: [0, 0], editor: { tooltip: '纹理尺寸' }}
cull_back: { value: 0, editor: { tooltip: '不显示背面, 0:关闭',range: [0, 1, 1] }}
顶点着色器 vs
CCProgram sprite-vs %{
precision highp float;
#include <builtin/uniforms/cc-global>
#include <common/common-define>
#if USE_LOCAL
#include <builtin/uniforms/cc-local>
#endif
#if SAMPLE_FROM_RT
// #include <common/common-define>
#endif
#if USE_FAKE3D
// 'out/in mediump' 作用为 'varying'
out mediump vec3 camera_pos;
out mediump vec2 offset;
uniform Fake3D_vs {
vec2 textureSize;
float FOV;
float y_rot;
float x_rot;
};
#endif
in vec3 a_position;
in vec2 a_texCoord;
in vec4 a_color;
out vec4 color;
out vec2 uv0;
vec4 vert () {
vec4 pos = vec4(a_position, 1);
#if USE_FAKE3D
vec2 UV = a_texCoord;
float sin_b = sin(y_rot / 180. * PI);
float cos_b = cos(y_rot / 180. * PI);
float sin_c = sin(x_rot / 180. * PI);
float cos_c = cos(x_rot / 180. * PI);
// Y轴旋转矩阵
mat3 inv_rot_mat_y = mat3(
vec3(cos_b, 0.0 , sin_b),
vec3(0.0 , 1.0 , 0.0),
vec3(-sin_b, 0.0 , cos_b)
);
// X轴旋转矩阵
mat3 inv_rot_mat_x = mat3(
vec3(1.0 , 0.0 , 0.0),
vec3(0.0 , cos_c , -sin_c),
vec3(0.0 , sin_c , cos_c)
);
// 合成的旋转矩阵
mat3 inv_rot_mat = inv_rot_mat_y * inv_rot_mat_x;
// 计算投影角度的正切
float t = tan(FOV / 360. * PI);
float v = (0.5 / t) + 0.5;
// 计算模拟的摄像机位置 和 偏移量
camera_pos = inv_rot_mat * vec3(UV - 0.5, 0.5 / t);
camera_pos.xy *= inv_rot_mat[2].z * v;
offset = inv_rot_mat[2].xy * v;
pos.x += (UV.x - 0.5) * textureSize.x;
pos.y -= (UV.y - 0.5) * textureSize.y;
#endif
#if USE_LOCAL
pos = cc_matWorld * pos;
#endif
#if USE_PIXEL_ALIGNMENT
pos = cc_matView * pos;
pos.xyz = floor(pos.xyz);
pos = cc_matProj * pos;
#else
pos = cc_matViewProj * pos;
#endif
uv0 = a_texCoord;
#if SAMPLE_FROM_RT
CC_HANDLE_RT_SAMPLE_FLIP(uv0);
#endif
color = a_color;
return pos;
}
}%
片段着色器 fs
CCProgram sprite-fs %{
precision highp float;
#include <builtin/internal/embedded-alpha>
#include <builtin/internal/alpha-test>
in vec4 color;
#if USE_TEXTURE
in vec2 uv0;
#pragma builtin(local)
layout(set = 2, binding = 12) uniform sampler2D cc_spriteTexture;
#endif
#if USE_FAKE3D
in mediump vec3 camera_pos;
in mediump vec2 offset;
uniform Fake3D_fs {
int cull_back;
};
#endif
vec4 frag () {
vec4 o = vec4(1, 1, 1, 1);
#if USE_TEXTURE
o *= CCSampleWithAlphaSeparated(cc_spriteTexture, uv0);
#if IS_GRAY
float gray = 0.2126 * o.r + 0.7152 * o.g + 0.0722 * o.b;
o.r = o.g = o.b = gray;
#endif
#if USE_FAKE3D
// 启用背面剔除 && 摄像机位置在背面 => 丢弃片段
if (cull_back != 0 && camera_pos.z <= 0.) discard;
// 将摄像机位置转换为屏幕上的 UV 坐标, 减去偏移量
vec2 uv = (camera_pos.xy / camera_pos.z).xy - offset;
// 纹理采样, 加上 0.5 以调整偏移
o = texture(cc_spriteTexture, uv + 0.5);
// 控制纹理的透明度，使超出范围的部分透明
o.a *= step(max(abs(uv.x), abs(uv.y)), 0.5);
#endif
#endif
o *= color;
ALPHA_TEST(o);
return o;
}
}%
脚本
import { _decorator, Component, EventMouse, Node, renderer, Sprite, tween, UITransform, v2, v3, Vec2 } from 'cc';
const { ccclass, property } = _decorator;
@ccclass('Fake3DCtrl')
export class Fake3DCtrl extends Component {
@property minAngle: number = -25;
@property maxAngle: number = 25;
private pass: renderer.Pass = null;
private y_rot: number = 0;
private x_rot: number = 0;
private spriteWidth: number = 0;
private spriteHeight: number = 0;
private lastYRot: number = 0;
private lastXRot: number = 0;
start(): void {
// 材质 初始化
const sprite = this.node.getComponent(Sprite);
this.spriteWidth = sprite.spriteFrame.width;
this.spriteHeight = sprite.spriteFrame.height;
const material = sprite.getMaterialInstance(0);
material.setProperty('textureSize', v2(this.spriteWidth , this.spriteHeight));
this.pass = material.passes[0];
this.y_rot = this.pass.getHandle('y_rot');
this.x_rot = this.pass.getHandle('x_rot');
// 监听鼠标移动
this.node.on(Node.EventType.MOUSE_ENTER, this.onMouseEnter, this);
this.node.on(Node.EventType.MOUSE_MOVE, this.onMouseMove, this);
this.node.on(Node.EventType.MOUSE_LEAVE, this.onMouseLeave, this);
}
onMouseEnter() {
tween(this.node)
.to(0.1, {scale: v3(1.5, 1.5, 1)})
.start();
}
onMouseMove(event: EventMouse) {
const screenPos = event.getUILocation();
const nodePos = this.node.getComponent(UITransform).convertToNodeSpaceAR(v3(screenPos.x, screenPos.y, 1));
const angleX = this.remap(nodePos.x, -this.spriteWidth/2, this.spriteWidth/2, this.minAngle, this.maxAngle);
const angleY = this.remap(nodePos.y, -this.spriteHeight/2, this.spriteHeight/2, this.minAngle, this.maxAngle);
this.pass.setUniform(this.y_rot, angleX);
this.pass.setUniform(this.x_rot, angleY);
this.lastYRot = angleX;
this.lastXRot = angleY;
}
onMouseLeave() {
tween(this.node)
.to(0.1, {scale: v3(1, 1, 1)})
.start();
// 缓慢改变材质属性
tween({ angleVec2: v2(this.lastYRot, this.lastXRot) })
.to(0.1, { angleVec2: Vec2.ZERO}, {
onUpdate: (target) => {
this.pass.setUniform(this.y_rot, target['angleVec2'].x);
this.pass.setUniform(this.x_rot, target['angleVec2'].y);
}
})
.call(()=>{
this.lastYRot = 0;
this.lastXRot = 0;
})
.start();
}
/**
* 映射
* @param num 当前值
* @param sourceMin 原最小值
* @param sourceMax 原最大值
* @param targetMin 目标最小值
* @param targetMax 目标最大值
* @returns 映射后的目标值
*/
remap(num: number ,sourceMin: number, sourceMax: number, targetMin: number = 0, targetMax: number = 1): number {
if (num < sourceMin || num > sourceMax) {
console.log(`Source Range Error: ${num} Not In [${sourceMin}, ${sourceMax}]`);
return;
}
if (sourceMin > sourceMax) {
console.log(`Source Range Error: sourceMin(${sourceMin}) > sourceMax(${sourceMax})`);
return;
}
if (targetMin > targetMax) {
console.log(`Target Range Error: targetMin(${targetMin}) > targetMax(${targetMax})`);
return;
}
const sourceRange = sourceMax - sourceMin;
const targetRange = targetMax - targetMin;
if (sourceRange === 0) {
console.log(`Source Range Warning: Source Range Is 0`);
return targetMin;
}
const normalizedNum = (num - sourceMin) / sourceRange;
return targetMin + (normalizedNum * targetRange);
}
}
效果
学习参考：
