拉到边界提示 shader

最新推荐文章于 2025-07-08 09:52:10 发布

转载最新推荐文章于 2025-07-08 09:52:10 发布 · 220 阅读

本文展示了一段使用 GLSL 进行三维场景绘制的着色器代码，通过定义距离场函数实现简单几何体的绘制，并运用光线追踪技术进行渲染。代码中详细展示了如何设置相机位置、方向以及如何进行光线行进和距离场计算。

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转载自： http://glslsandbox.com/e#43731.0

#ifdef GL_ES
precision mediump float;
#endif

#extension GL_OES_standard_derivatives : enable

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

float sdBox( vec2 p, vec2 b )
{
vec2 d = abs(p) - b;
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}

float map(vec3 p)
{
float h = 1.8;
float grid = 0.4;
float grid_half = grid*0.5;
float cube = 0.175;

p = -abs(p);
float d1 = p.y + h;
vec2 p1 = mod(p.xz, vec2(grid)) - vec2(grid_half);
float c1 = sdBox(p1,vec2(cube));

return max(c1,d1);
}

void main()
{
vec2 pos = (gl_FragCoord.xy*2.0 - resolution.xy) / resolution.y;
vec3 camPos = vec3(-0.5,0.0,3.0);
vec3 camDir = normalize(vec3(0.3, 0.0, -1.0));
camPos -= vec3(0.0,0.0,time*3.0);
vec3 camUp = normalize(vec3(0.5, 1.0, 0.0));
vec3 camSide = cross(camDir, camUp);
float focus = 1.8;

vec3 rayDir = normalize(camSide*pos.x + camUp*pos.y + camDir*focus);
vec3 ray = camPos;
int march = 0;
float d = 0.0;

float total_d = 0.0;
const int MAX_MARCH = 64;
const float MAX_DIST = 100.0;
for(int mi=0; mi<MAX_MARCH; ++mi) {
d = map(ray);
march=mi;
total_d += d;
ray += rayDir * d;
if(d<0.001) {break; }
if(total_d>MAX_DIST) {
total_d = MAX_DIST;
march = MAX_MARCH-1;
break;
}
}

float fog = min(1.0, (1.0 / float(MAX_MARCH)) * float(march))*1.0;
vec3 fog2 = 0.01 * vec3(1, 1, 1.5) * total_d;
gl_FragColor = vec4(vec3(0.15, 0.15, 0.2)*fog + fog2, 1.0);
}