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/* Infinite grid
* Clément Foucault */
in vec3 wPos;
out vec4 FragColor;
uniform mat4 ProjectionMatrix;
uniform vec3 cameraPos;
uniform vec3 eye;
uniform vec4 gridSettings;
uniform float gridOneOverLogSubdiv;
#define gridDistance gridSettings.x
#define gridResolution gridSettings.y
#define gridScale gridSettings.z
#define gridSubdiv gridSettings.w
uniform int gridFlag;
#define AXIS_X (1 << 0)
#define AXIS_Y (1 << 1)
#define AXIS_Z (1 << 2)
#define GRID (1 << 3)
#define PLANE_XY (1 << 4)
#define PLANE_XZ (1 << 5)
#define PLANE_YZ (1 << 6)
#define GRID_LINE_SMOOTH 1.15
float grid(vec3 uv, vec3 fwidthCos, float grid_size)
{
float half_size = grid_size / 2.0;
/* triangular wave pattern, amplitude is [0, grid_size] */
vec3 grid_domain = abs(mod(uv + half_size, grid_size) - half_size);
/* modulate by the absolute rate of change of the uvs
* (make lines have the same width under perspective) */
grid_domain /= fwidthCos;
/* collapse waves and normalize */
grid_domain.x = min(grid_domain.x, min(grid_domain.y, grid_domain.z)) / grid_size;
return 1.0 - smoothstep(0.0, GRID_LINE_SMOOTH / grid_size, grid_domain.x);
}
float axis(float u, float fwidthU, float line_size)
{
float axis_domain = abs(u);
/* modulate by the absolute rate of change of the uvs
* (make line have the same width under perspective) */
axis_domain /= fwidthU;
return 1.0 - smoothstep(0.0, GRID_LINE_SMOOTH, axis_domain - line_size);
}
void main()
{
vec3 fwidthCos = fwidth(wPos);
float dist, fade;
/* if persp */
if (ProjectionMatrix[3][3] == 0.0) {
vec3 viewvec = cameraPos - wPos;
dist = length(viewvec);
viewvec /= dist;
float angle;
if ((gridFlag & PLANE_XZ) > 0)
angle = viewvec.y;
else if ((gridFlag & PLANE_YZ) > 0)
angle = viewvec.x;
else
angle = viewvec.z;
angle = 1.0 - abs(angle);
fade = 1.0 - angle * angle;
fade *= 1.0 - smoothstep(0.0, gridDistance, dist - gridDistance);
}
else {
dist = abs(gl_FragCoord.z * 2.0 - 1.0);
fade = 1.0 - smoothstep(0.0, 0.5, dist - 0.5);
dist = 1.0; /* avoid branch after */
if ((gridFlag & PLANE_XY) > 0) {
float angle = 1.0 - abs(eye.z);
fade *= 1.0 - angle * angle * angle;
dist = 1.0 + angle * 2.0;
}
}
if ((gridFlag & GRID) > 0) {
float grid_res = log(dist * gridResolution) * gridOneOverLogSubdiv;
float blend = fract(-max(grid_res, 0.0));
float lvl = floor(grid_res);
/* from smallest to biggest */
float scaleA = gridScale * pow(gridSubdiv, max(lvl - 1.0, 0.0));
float scaleB = gridScale * pow(gridSubdiv, max(lvl + 0.0, 0.0));
float scaleC = gridScale * pow(gridSubdiv, max(lvl + 1.0, 1.0));
float gridA = grid(wPos, fwidthCos, scaleA);
float gridB = grid(wPos, fwidthCos, scaleB);
float gridC = grid(wPos, fwidthCos, scaleC);
FragColor = vec4(colorGrid.rgb, gridA * blend);
FragColor = mix(FragColor, vec4(mix(colorGrid.rgb, colorGridEmphasise.rgb, blend), 1.0), gridB);
FragColor = mix(FragColor, vec4(colorGridEmphasise.rgb, 1.0), gridC);
}
else {
FragColor = vec4(colorGrid.rgb, 0.0);
}
if ((gridFlag & AXIS_X) > 0) {
float xAxis;
if ((gridFlag & PLANE_XZ) > 0) {
xAxis = axis(wPos.z, fwidthCos.z, 0.1);
}
else {
xAxis = axis(wPos.y, fwidthCos.y, 0.1);
}
FragColor = mix(FragColor, colorGridAxisX, xAxis);
}
if ((gridFlag & AXIS_Y) > 0) {
float yAxis;
if ((gridFlag & PLANE_YZ) > 0) {
yAxis = axis(wPos.z, fwidthCos.z, 0.1);
}
else {
yAxis = axis(wPos.x, fwidthCos.x, 0.1);
}
FragColor = mix(FragColor, colorGridAxisY, yAxis);
}
if ((gridFlag & AXIS_Z) > 0) {
float zAxis;
if ((gridFlag & PLANE_YZ) > 0) {
zAxis = axis(wPos.y, fwidthCos.y, 0.1);
}
else {
zAxis = axis(wPos.x, fwidthCos.x, 0.1);
}
FragColor = mix(FragColor, colorGridAxisZ, zAxis);
}
FragColor.a *= fade;
}
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