0.8.13

shader/lightRender.cs

@@ -0,0 +1,30 @@
+#define PI 3.14
+extern float xresolution;
+//从1D距离map采样
+float samp(vec2 coord,float r,Image u_texture){
+	return step(r,Texel(u_texture,coord).r);
+}
+vec4 effect(vec4 color,Image texture,vec2 texture_coords,vec2 screen_coords){
+	//直角转极坐标，用于采样1D材质的y总是0
+	vec2 norm=texture_coords.st*2.-1.;
+	float r=length(norm);
+	vec2 tc=vec2((atan(norm.y,norm.x)+PI)/(2.*PI),0.);
+	//根据离光源距离放大模糊系数，模拟影子淡出
+	float blur=(1./xresolution)*smoothstep(0.,1.,r);
+
+	//简易高斯模糊
+	float sum=
+		samp(vec2(tc.x-4.*blur,tc.y),r,texture)*.5
+		+samp(vec2(tc.x-3.*blur,tc.y),r,texture)*.9
+		+samp(vec2(tc.x-2.*blur,tc.y),r,texture)*.12
+		+samp(vec2(tc.x-1.*blur,tc.y),r,texture)*.15
+
+		+samp(tc,r,texture)*.16//The center tex coord,which gives us hard shadows.
+		+samp(vec2(tc.x+1.*blur,tc.y),r,texture)*.15
+		+samp(vec2(tc.x+2.*blur,tc.y),r,texture)*.12
+		+samp(vec2(tc.x+3.*blur,tc.y),r,texture)*.9
+		+samp(vec2(tc.x+4.*blur,tc.y),r,texture)*.5;
+	//sum值为亮度(0~1)
+	//乘上距离得到逐渐变淡的光线
+	return vec4(vec3(1.),sum*smoothstep(1.,.1,r));
+}