Ray-caster: highlight intersections and cusps
This commit is contained in:
Aaron Fenyes
parent
f1029b3102
commit
e3df765f16
@ -72,6 +72,8 @@ fn main() {
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sycamore::render(|| {
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let ctrl_x = create_signal(0.0);
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let ctrl_y = create_signal(0.0);
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let radius_x = create_signal(1.0);
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let radius_y = create_signal(1.0);
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let opacity = create_signal(0.5);
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let layer_threshold = create_signal(0.0);
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let display = create_node_ref();
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@ -116,12 +118,14 @@ fn main() {
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// controls
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uniform vec2 ctrl;
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uniform vec2 radius;
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uniform float opacity;
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uniform int layer_threshold;
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// light and camera
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const float focal_slope = 0.3;
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const vec3 light_dir = normalize(vec3(2., 2., 1.));
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const float ixn_threshold = 0.005;
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// --- sRGB ---
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@ -170,13 +174,15 @@ fn main() {
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// --- shading ---
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struct taggedFrag {
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int id;
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vec4 color;
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float depth;
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vec3 pt;
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vec3 normal;
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};
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taggedFrag[2] sort(taggedFrag a, taggedFrag b) {
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taggedFrag[2] result;
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if (a.depth < b.depth) {
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if (a.pt.z > b.pt.z) {
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result[0] = a;
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result[1] = b;
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} else {
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@ -186,7 +192,7 @@ fn main() {
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return result;
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}
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taggedFrag sphere_shading(vecInv v, vec3 pt, vec3 base_color) {
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taggedFrag sphere_shading(vecInv v, vec3 pt, vec3 base_color, int id) {
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// the expression for normal needs to be checked. it's
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// supposed to give the negative gradient of the lorentz
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// product between the impact point vector and the sphere
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@ -197,7 +203,7 @@ fn main() {
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float incidence = dot(normal, light_dir);
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float illum = mix(0.4, 1.0, max(incidence, 0.0));
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return taggedFrag(vec4(illum * base_color, opacity), -pt.z);
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return taggedFrag(id, vec4(illum * base_color, opacity), pt, normal);
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}
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// --- ray-casting ---
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@ -228,23 +234,24 @@ fn main() {
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vec3 dir = vec3(focal_slope * scr, -1.);
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// initialize two spheres
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vecInv v0 = sphere(vec3(0.5, 0.5, -5. + ctrl.x), 1.);
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vecInv v1 = sphere(vec3(-0.5, -0.5, -5. + ctrl.y), 1.);
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vecInv v [2];
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v[0] = sphere(vec3(0.5, 0.5, -5. + ctrl.x), radius.x);
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v[1] = sphere(vec3(-0.5, -0.5, -5. + ctrl.y), radius.y);
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vec3 color0 = vec3(1., 0.214, 0.);
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vec3 color1 = vec3(0., 0.214, 1.);
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// cast rays through the spheres
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vec2 u0 = sphere_cast(v0, dir);
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vec2 u1 = sphere_cast(v1, dir);
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vec2 u0 = sphere_cast(v[0], dir);
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vec2 u1 = sphere_cast(v[1], dir);
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// shade and depth-sort the impact points
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taggedFrag front_hits[2] = sort(
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sphere_shading(v0, u0[0] * dir, color0),
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sphere_shading(v1, u1[0] * dir, color1)
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sphere_shading(v[0], u0[0] * dir, color0, 0),
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sphere_shading(v[1], u1[0] * dir, color1, 1)
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);
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taggedFrag back_hits[2] = sort(
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sphere_shading(v0, u0[1] * dir, color0),
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sphere_shading(v1, u1[1] * dir, color1)
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sphere_shading(v[0], u0[1] * dir, color0, 0),
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sphere_shading(v[1], u1[1] * dir, color1, 1)
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);
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taggedFrag middle_frags[2] = sort(front_hits[1], back_hits[0]);
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@ -255,10 +262,32 @@ fn main() {
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frags_by_depth[2] = middle_frags[1];
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frags_by_depth[3] = back_hits[1];
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// highlight intersections and cusps
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for (int i = 3; i >= 1; --i) {
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// intersections
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taggedFrag frag0 = frags_by_depth[i];
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taggedFrag frag1 = frags_by_depth[i-1];
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float ixn_sin = length(cross(frag0.normal, frag1.normal));
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vec3 disp = frag0.pt - frag1.pt;
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float ixn_dist = max(
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abs(dot(frag1.normal, disp)),
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abs(dot(frag0.normal, disp))
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) / ixn_sin;
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float ixn_highlight = 1. - smoothstep(2./3.*ixn_threshold, 1.5*ixn_threshold, ixn_dist);
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frags_by_depth[i].color = mix(frags_by_depth[i].color, vec4(1.), ixn_highlight);
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frags_by_depth[i-1].color = mix(frags_by_depth[i-1].color, vec4(1.), ixn_highlight);
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// cusps
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float cusp_cos = abs(dot(dir, frag0.normal));
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float cusp_threshold = 2.*sqrt(ixn_threshold * v[frag0.id].lt.s);
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float cusp_highlight = 1. - smoothstep(2./3.*cusp_threshold, 1.5*cusp_threshold, cusp_cos);
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frags_by_depth[i].color = mix(frags_by_depth[i].color, vec4(1.), cusp_highlight);
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}
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// composite the sphere fragments
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vec3 color = vec3(0.);
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for (int i = 3; i >= layer_threshold; --i) {
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if (frags_by_depth[i].depth > 0.) {
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if (frags_by_depth[i].pt.z < 0.) {
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vec4 frag_color = frags_by_depth[i].color;
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color = mix(color, frag_color.rgb, frag_color.a);
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}
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@ -288,6 +317,7 @@ fn main() {
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let resolution_loc = ctx.get_uniform_location(&program, "resolution");
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let shortdim_loc = ctx.get_uniform_location(&program, "shortdim");
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let ctrl_loc = ctx.get_uniform_location(&program, "ctrl");
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let radius_loc = ctx.get_uniform_location(&program, "radius");
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let opacity_loc = ctx.get_uniform_location(&program, "opacity");
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let layer_threshold_loc = ctx.get_uniform_location(&program, "layer_threshold");
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@ -319,6 +349,7 @@ fn main() {
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// pass the control parameters
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ctx.uniform2f(ctrl_loc.as_ref(), ctrl_x.get() as f32, ctrl_y.get() as f32);
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ctx.uniform2f(radius_loc.as_ref(), radius_x.get() as f32, radius_y.get() as f32);
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ctx.uniform1f(opacity_loc.as_ref(), opacity.get() as f32);
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ctx.uniform1i(layer_threshold_loc.as_ref(), layer_threshold.get() as i32);
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@ -346,6 +377,20 @@ fn main() {
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step=0.001,
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bind:valueAsNumber=ctrl_y
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)
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input(
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type="range",
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min=0.5,
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max=1.5,
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step=0.001,
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bind:valueAsNumber=radius_x
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)
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input(
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type="range",
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min=0.5,
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max=1.5,
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step=0.001,
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bind:valueAsNumber=radius_y
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)
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input(
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type="range",
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max=1.0,
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