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glsl_snippets
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/////////////////////////////////////////////// | |
// glsl snippets: credit given where i could // | |
/////////////////////////////////////////////// | |
/////////////////// | |
// inverse matrices | |
// credit to: https://github.com/glslify/glsl-inverse/blob/master/index.glsl | |
float inverse(float m) { | |
return 1.0 / m; | |
} | |
mat2 inverse(mat2 m) { | |
return mat2(m[1][1],-m[0][1], | |
-m[1][0], m[0][0]) / (m[0][0]*m[1][1] - m[0][1]*m[1][0]); | |
} | |
mat3 inverse(mat3 m) { | |
float a00 = m[0][0], a01 = m[0][1], a02 = m[0][2]; | |
float a10 = m[1][0], a11 = m[1][1], a12 = m[1][2]; | |
float a20 = m[2][0], a21 = m[2][1], a22 = m[2][2]; | |
float b01 = a22 * a11 - a12 * a21; | |
float b11 = -a22 * a10 + a12 * a20; | |
float b21 = a21 * a10 - a11 * a20; | |
float det = a00 * b01 + a01 * b11 + a02 * b21; | |
return mat3(b01, (-a22 * a01 + a02 * a21), (a12 * a01 - a02 * a11), | |
b11, (a22 * a00 - a02 * a20), (-a12 * a00 + a02 * a10), | |
b21, (-a21 * a00 + a01 * a20), (a11 * a00 - a01 * a10)) / det; | |
} | |
mat4 inverse(mat4 m) { | |
float | |
a00 = m[0][0], a01 = m[0][1], a02 = m[0][2], a03 = m[0][3], | |
a10 = m[1][0], a11 = m[1][1], a12 = m[1][2], a13 = m[1][3], | |
a20 = m[2][0], a21 = m[2][1], a22 = m[2][2], a23 = m[2][3], | |
a30 = m[3][0], a31 = m[3][1], a32 = m[3][2], a33 = m[3][3], | |
b00 = a00 * a11 - a01 * a10, | |
b01 = a00 * a12 - a02 * a10, | |
b02 = a00 * a13 - a03 * a10, | |
b03 = a01 * a12 - a02 * a11, | |
b04 = a01 * a13 - a03 * a11, | |
b05 = a02 * a13 - a03 * a12, | |
b06 = a20 * a31 - a21 * a30, | |
b07 = a20 * a32 - a22 * a30, | |
b08 = a20 * a33 - a23 * a30, | |
b09 = a21 * a32 - a22 * a31, | |
b10 = a21 * a33 - a23 * a31, | |
b11 = a22 * a33 - a23 * a32, | |
det = b00 * b11 - b01 * b10 + b02 * b09 + b03 * b08 - b04 * b07 + b05 * b06; | |
return mat4( | |
a11 * b11 - a12 * b10 + a13 * b09, | |
a02 * b10 - a01 * b11 - a03 * b09, | |
a31 * b05 - a32 * b04 + a33 * b03, | |
a22 * b04 - a21 * b05 - a23 * b03, | |
a12 * b08 - a10 * b11 - a13 * b07, | |
a00 * b11 - a02 * b08 + a03 * b07, | |
a32 * b02 - a30 * b05 - a33 * b01, | |
a20 * b05 - a22 * b02 + a23 * b01, | |
a10 * b10 - a11 * b08 + a13 * b06, | |
a01 * b08 - a00 * b10 - a03 * b06, | |
a30 * b04 - a31 * b02 + a33 * b00, | |
a21 * b02 - a20 * b04 - a23 * b00, | |
a11 * b07 - a10 * b09 - a12 * b06, | |
a00 * b09 - a01 * b07 + a02 * b06, | |
a31 * b01 - a30 * b03 - a32 * b00, | |
a20 * b03 - a21 * b01 + a22 * b00) / det; | |
} | |
///////////////////// | |
// transpose matrices | |
// credit to: https://github.com/glslify/glsl-transpose/blob/master/index.glsl | |
float transpose(float m) { | |
return m; | |
} | |
mat2 transpose(mat2 m) { | |
return mat2(m[0][0], m[1][0], | |
m[0][1], m[1][1]); | |
} | |
mat3 transpose(mat3 m) { | |
return mat3(m[0][0], m[1][0], m[2][0], | |
m[0][1], m[1][1], m[2][1], | |
m[0][2], m[1][2], m[2][2]); | |
} | |
mat4 transpose(mat4 m) { | |
return mat4(m[0][0], m[1][0], m[2][0], m[3][0], | |
m[0][1], m[1][1], m[2][1], m[3][1], | |
m[0][2], m[1][2], m[2][2], m[3][2], | |
m[0][3], m[1][3], m[2][3], m[3][3]); | |
} | |
/////////////////// | |
// project on plane | |
// credit to: https://github.com/mrdoob/three.js/blob/dev/src/renderers/shaders/ShaderChunk/common.glsl.js | |
vec3 projectOnPlane(in vec3 point, in vec3 pointOnPlane, in vec3 planeNormal ) { | |
float distance = dot( planeNormal, point - pointOnPlane ); | |
return - distance * planeNormal + point; | |
} | |
//////////////// | |
// side of plane | |
// credit to: https://github.com/mrdoob/three.js/blob/dev/src/renderers/shaders/ShaderChunk/common.glsl.js | |
float sideOfPlane( in vec3 point, in vec3 pointOnPlane, in vec3 planeNormal ) { | |
return sign( dot( point - pointOnPlane, planeNormal ) ); | |
} | |
/////////////////////// | |
// line plane intersect | |
// credit to: https://github.com/mrdoob/three.js/blob/dev/src/renderers/shaders/ShaderChunk/common.glsl.js | |
vec3 linePlaneIntersect( in vec3 pointOnLine, in vec3 lineDirection, in vec3 pointOnPlane, in vec3 planeNormal ) { | |
return lineDirection * ( dot( planeNormal, pointOnPlane - pointOnLine ) / dot( planeNormal, lineDirection ) ) + pointOnLine; | |
} | |
///////////////// | |
// look at matrix | |
// get look at matrix | |
"mat4 lookAtMatrix( vec3 vertex, vec3 target, vec3 up ) {", | |
"vec3 zaxis = normalize( vertex - target );", | |
"vec3 xaxis = normalize( cross( zaxis, up ) );", | |
"vec3 yaxis = cross( xaxis, zaxis );", | |
"zaxis *= -1.0;", | |
"mat4 m = mat4(", | |
"vec4(xaxis.x, xaxis.y, xaxis.z, -dot(xaxis, vertex)),", | |
"vec4(yaxis.x, yaxis.y, yaxis.z, -dot(yaxis, vertex)),", | |
"vec4(zaxis.x, zaxis.y, zaxis.z, -dot(zaxis, vertex)),", | |
"vec4(0, 0, 0, 1)", | |
");", | |
"return m;", | |
"}", | |
////////////////// | |
// cylindrical uvs | |
// credit to https://forum.unity.com/threads/applying-decal-texture-at-runtime-without-planar-projection.696275/ | |
float2 cylindricalUV = saturate(float2(atan2(objPos.z, objPos.x) / (0.5 * PI) + 0.5, objPos.y + 0.5)); // could also be world position |
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