Difference between revisions of "GLSL snippets"
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== Ray marching == | == Ray marching == | ||
− | < | + | <source lang="GLSL"> |
// http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/ | // http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/ | ||
vec3 rayDirection(float fieldOfView, vec2 size, vec2 fragCoord) { | vec3 rayDirection(float fieldOfView, vec2 size, vec2 fragCoord) { | ||
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return normalize(vec3(xy, -z)); | return normalize(vec3(xy, -z)); | ||
} | } | ||
− | </ | + | </source> |
− | < | + | <source lang="GLSL"> |
// http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/ | // http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/ | ||
float castRay(const int scene, vec3 eye, vec3 dir, | float castRay(const int scene, vec3 eye, vec3 dir, | ||
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return end; | return end; | ||
} | } | ||
− | </ | + | </source> |
− | < | + | <source lang="GLSL"> |
// http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm | // http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm | ||
vec3 estimateNormal( const int scene, const float epsilon, in vec3 p ) | vec3 estimateNormal( const int scene, const float epsilon, in vec3 p ) | ||
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k.xxx*sceneSDF( scene, p + k.xxx*epsilon, m ) ); | k.xxx*sceneSDF( scene, p + k.xxx*epsilon, m ) ); | ||
} | } | ||
− | </ | + | </source> |
== Matrix transformations == | == Matrix transformations == | ||
− | < | + | <source lang="GLSL"> |
// https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glRotate.xml | // https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glRotate.xml | ||
mat4 rotate(float a, vec3 v) | mat4 rotate(float a, vec3 v) | ||
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); | ); | ||
} | } | ||
− | </ | + | </source> |
− | < | + | <source lang="GLSL"> |
// https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glTranslate.xml | // https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glTranslate.xml | ||
mat4 translate(vec3 v) | mat4 translate(vec3 v) | ||
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); | ); | ||
} | } | ||
− | </ | + | </source> |
== Noise == | == Noise == | ||
− | < | + | <source lang="GLSL"> |
// https://stackoverflow.com/questions/12964279/whats-the-origin-of-this-glsl-rand-one-liner | // https://stackoverflow.com/questions/12964279/whats-the-origin-of-this-glsl-rand-one-liner | ||
float rand(vec2 co) | float rand(vec2 co) | ||
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return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453); | return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453); | ||
} | } | ||
− | </ | + | </source> |
[[Category:Programming]] | [[Category:Programming]] |
Revision as of 21:56, 13 December 2019
Ray marching
// http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/
vec3 rayDirection(float fieldOfView, vec2 size, vec2 fragCoord) {
vec2 xy = fragCoord - size / 2.0;
float z = size.y / tan(radians(fieldOfView) / 2.0);
return normalize(vec3(xy, -z));
}
// http://jamie-wong.com/2016/07/15/ray-marching-signed-distance-functions/
float castRay(const int scene, vec3 eye, vec3 dir,
float start, float end, float epsilon, int max_marching_steps,
out int material)
{
float depth = start;
for (int i = 0; i < max_marching_steps; i++) {
float d = sceneSDF(scene, eye + depth * dir, material);
if (d < epsilon)
return depth;
depth += d;
if (depth >= end)
break;
}
return end;
}
// http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm
vec3 estimateNormal( const int scene, const float epsilon, in vec3 p )
{
int m;
const vec2 k = vec2(1,-1);
return normalize( k.xyy*sceneSDF( scene, p + k.xyy*epsilon, m ) +
k.yyx*sceneSDF( scene, p + k.yyx*epsilon, m ) +
k.yxy*sceneSDF( scene, p + k.yxy*epsilon, m ) +
k.xxx*sceneSDF( scene, p + k.xxx*epsilon, m ) );
}
Matrix transformations
// https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glRotate.xml
mat4 rotate(float a, vec3 v)
{
float c = cos(a);
vec3 ci = (1. - c) * v;
vec3 s = sin(a) * v;
return mat4(
ci.x * v.x + c, ci.x * v.y + s.z, ci.x * v.z - s.y, 0,
ci.y * v.x - s.z, ci.y * v.y + c, ci.y * v.z + s.x, 0,
ci.z * v.x + s.y, ci.z * v.y - s.x, ci.z * v.z + c, 0,
0, 0, 0, 1
);
}
// https://www.khronos.org/registry/OpenGL-Refpages/gl2.1/xhtml/glTranslate.xml
mat4 translate(vec3 v)
{
return mat4(
1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
v.x, v.y, v.z, 1
);
}
Noise
// https://stackoverflow.com/questions/12964279/whats-the-origin-of-this-glsl-rand-one-liner
float rand(vec2 co)
{
return fract(sin(dot(co.xy, vec2(12.9898, 78.233))) * 43758.5453);
}