playcanvas/build/playcanvas/src/scene/shader-lib/chunks/gsplat/vert/gsplatCorner.js

PlayCanvas WebGL game engine

var gsplatCornerVS = "\nuniform vec2 viewport;\nuniform vec4 camera_params;\nbool initCorner(SplatSource source, SplatCenter center, out SplatCorner corner) {\n	vec3 covA, covB;\n	readCovariance(source, covA, covB);\n	mat3 Vrk = mat3(\n		covA.x, covA.y, covA.z, \n		covA.y, covB.x, covB.y,\n		covA.z, covB.y, covB.z\n	);\n	float focal = viewport.x * center.projMat00;\n	vec3 v = camera_params.w == 1.0 ? vec3(0.0, 0.0, 1.0) : center.view.xyz;\n	float J1 = focal / v.z;\n	vec2 J2 = -J1 / v.z * v.xy;\n	mat3 J = mat3(\n		J1, 0.0, J2.x, \n		0.0, J1, J2.y, \n		0.0, 0.0, 0.0\n	);\n	mat3 W = transpose(mat3(center.modelView));\n	mat3 T = W * J;\n	mat3 cov = transpose(T) * Vrk * T;\n	float diagonal1 = cov[0][0] + 0.3;\n	float offDiagonal = cov[0][1];\n	float diagonal2 = cov[1][1] + 0.3;\n	float mid = 0.5 * (diagonal1 + diagonal2);\n	float radius = length(vec2((diagonal1 - diagonal2) / 2.0, offDiagonal));\n	float lambda1 = mid + radius;\n	float lambda2 = max(mid - radius, 0.1);\n	float l1 = 2.0 * min(sqrt(2.0 * lambda1), 1024.0);\n	float l2 = 2.0 * min(sqrt(2.0 * lambda2), 1024.0);\n	if (l1 < 2.0 && l2 < 2.0) {\n		return false;\n	}\n	if (any(greaterThan(abs(center.proj.xy) - vec2(l1, l2) / viewport * center.proj.w, center.proj.ww))) {\n		return false;\n	}\n	vec2 diagonalVector = normalize(vec2(offDiagonal, lambda1 - diagonal1));\n	vec2 v1 = l1 * diagonalVector;\n	vec2 v2 = l2 * vec2(diagonalVector.y, -diagonalVector.x);\n	corner.offset = (source.cornerUV.x * v1 + source.cornerUV.y * v2) / viewport * center.proj.w;\n	corner.uv = source.cornerUV;\n	return true;\n}\n";

export { gsplatCornerVS as default };