Ray-cast two spheres, with hard-coded depth sorting
This commit is contained in:
Aaron Fenyes
parent
d2cecf69db
commit
2ef0fdd3e2
@ -73,6 +73,7 @@ fn main() {
|
||||
let ctrl_x = create_signal(0.0);
|
||||
let ctrl_y = create_signal(0.0);
|
||||
let opacity = create_signal(0.6);
|
||||
let layer_threshold = create_signal(0.0);
|
||||
let display = create_node_ref();
|
||||
|
||||
on_mount(move || {
|
||||
@ -116,11 +117,14 @@ fn main() {
|
||||
// controls
|
||||
uniform vec2 ctrl;
|
||||
uniform float opacity;
|
||||
uniform int layer_threshold;
|
||||
|
||||
// light and camera
|
||||
const float focal_slope = 0.3;
|
||||
const vec3 light_dir = normalize(vec3(2., 2., 1.));
|
||||
|
||||
// --- inversive geometry ---
|
||||
|
||||
struct vecInv {
|
||||
vec3 sp;
|
||||
vec2 lt;
|
||||
@ -136,7 +140,26 @@ fn main() {
|
||||
);
|
||||
}
|
||||
|
||||
vec4 shade_sphere(vecInv v, vec3 pt) {
|
||||
// --- shading ---
|
||||
|
||||
struct taggedFrag {
|
||||
vec4 color;
|
||||
float depth;
|
||||
};
|
||||
|
||||
taggedFrag[2] sort(taggedFrag a, taggedFrag b) {
|
||||
taggedFrag[2] result;
|
||||
if (a.depth < b.depth) {
|
||||
result[0] = a;
|
||||
result[1] = b;
|
||||
} else {
|
||||
result[0] = b;
|
||||
result[1] = a;
|
||||
}
|
||||
return result;
|
||||
}
|
||||
|
||||
taggedFrag sphere_shading(vecInv v, vec3 pt, vec3 base_color) {
|
||||
// the expression for normal needs to be checked. it's
|
||||
// supposed to give the negative gradient of the lorentz
|
||||
// product between the impact point vector and the sphere
|
||||
@ -147,20 +170,13 @@ fn main() {
|
||||
|
||||
vec3 color;
|
||||
float incidence = dot(normal_front, light_dir);
|
||||
if (incidence < 0.) {
|
||||
color = mix(vec3(0.2, 0.0, 0.4), vec3(0.1, 0.0, 0.2), -incidence);
|
||||
} else {
|
||||
color = mix(vec3(0.4, 0.0, 0.2), vec3(1.0, 0.8, 1.0), incidence);
|
||||
}
|
||||
return vec4(color, opacity);
|
||||
float illum = mix(0.4, 1.0, max(incidence, 0.0));
|
||||
return taggedFrag(vec4(illum * base_color, opacity), -pt.z);
|
||||
}
|
||||
|
||||
void main() {
|
||||
vec2 scr = (2.*gl_FragCoord.xy - resolution) / shortdim;
|
||||
vec3 dir = vec3(focal_slope * scr, -1.);
|
||||
|
||||
vecInv v = sphere(vec3(ctrl, -5.), 1.);
|
||||
|
||||
// --- ray-casting ---
|
||||
|
||||
vec2 sphere_cast(vecInv v, vec3 dir) {
|
||||
float a = -v.lt.s * dot(dir, dir);
|
||||
float b = dot(v.sp, dir);
|
||||
float c = -v.lt.t;
|
||||
@ -168,18 +184,57 @@ fn main() {
|
||||
float scale = -b/(2.*a);
|
||||
float adjust = 4.*a*c/(b*b);
|
||||
|
||||
vec3 color = vec3(0.);
|
||||
if (adjust < 1.) {
|
||||
float offset = sqrt(1. - adjust);
|
||||
float u_front = scale * (1. - offset);
|
||||
float u_back = scale * (1. + offset);
|
||||
if (u_back > 0.) {
|
||||
vec4 sphere_color = shade_sphere(v, u_back * dir);
|
||||
color = mix(color, sphere_color.rgb, sphere_color.a);
|
||||
}
|
||||
if (u_front > 0.) {
|
||||
vec4 sphere_color = shade_sphere(v, u_front * dir);
|
||||
color = mix(color, sphere_color.rgb, sphere_color.a);
|
||||
return vec2(
|
||||
scale * (1. - offset),
|
||||
scale * (1. + offset)
|
||||
);
|
||||
} else {
|
||||
// these parameters describe points behind the camera,
|
||||
// so the corresponding fragments won't be drawn
|
||||
return vec2(-1., -1.);
|
||||
}
|
||||
}
|
||||
|
||||
void main() {
|
||||
vec2 scr = (2.*gl_FragCoord.xy - resolution) / shortdim;
|
||||
vec3 dir = vec3(focal_slope * scr, -1.);
|
||||
|
||||
// initialize two spheres
|
||||
vecInv v0 = sphere(vec3(0.5, 0.5, -5. + ctrl.x), 1.);
|
||||
vecInv v1 = sphere(vec3(-0.5, -0.5, -5. + ctrl.y), 1.);
|
||||
vec3 color0 = vec3(1.0, 0.5, 0.0);
|
||||
vec3 color1 = vec3(0.0, 0.5, 1.0);
|
||||
|
||||
// cast rays through the spheres
|
||||
vec2 u0 = sphere_cast(v0, dir);
|
||||
vec2 u1 = sphere_cast(v1, dir);
|
||||
|
||||
// shade and depth-sort the impact points
|
||||
taggedFrag front_hits[2] = sort(
|
||||
sphere_shading(v0, u0[0] * dir, color0),
|
||||
sphere_shading(v1, u1[0] * dir, color1)
|
||||
);
|
||||
taggedFrag back_hits[2] = sort(
|
||||
sphere_shading(v0, u0[1] * dir, color0),
|
||||
sphere_shading(v1, u1[1] * dir, color1)
|
||||
);
|
||||
taggedFrag middle_frags[2] = sort(front_hits[1], back_hits[0]);
|
||||
|
||||
// finish depth sorting
|
||||
taggedFrag frags_by_depth[4];
|
||||
frags_by_depth[0] = front_hits[0];
|
||||
frags_by_depth[1] = middle_frags[0];
|
||||
frags_by_depth[2] = middle_frags[1];
|
||||
frags_by_depth[3] = back_hits[1];
|
||||
|
||||
// composite the sphere fragments
|
||||
vec3 color = vec3(0.);
|
||||
for (int i = 3; i >= layer_threshold; --i) {
|
||||
if (frags_by_depth[i].depth > 0.) {
|
||||
vec4 frag_color = frags_by_depth[i].color;
|
||||
color = mix(color, frag_color.rgb, frag_color.a);
|
||||
}
|
||||
}
|
||||
outColor = vec4(color, 1.);
|
||||
@ -208,6 +263,7 @@ fn main() {
|
||||
let shortdim_loc = ctx.get_uniform_location(&program, "shortdim");
|
||||
let ctrl_loc = ctx.get_uniform_location(&program, "ctrl");
|
||||
let opacity_loc = ctx.get_uniform_location(&program, "opacity");
|
||||
let layer_threshold_loc = ctx.get_uniform_location(&program, "layer_threshold");
|
||||
|
||||
// create a vertex array and bind it to the graphics context
|
||||
let vertex_array = ctx.create_vertex_array().unwrap();
|
||||
@ -238,6 +294,7 @@ fn main() {
|
||||
// pass the control parameters
|
||||
ctx.uniform2f(ctrl_loc.as_ref(), ctrl_x.get() as f32, ctrl_y.get() as f32);
|
||||
ctx.uniform1f(opacity_loc.as_ref(), opacity.get() as f32);
|
||||
ctx.uniform1i(layer_threshold_loc.as_ref(), layer_threshold.get() as i32);
|
||||
|
||||
// clear the screen and draw the scene
|
||||
ctx.clear_color(0.0, 0.0, 0.0, 1.0);
|
||||
@ -253,22 +310,28 @@ fn main() {
|
||||
type="range",
|
||||
min=-1.0,
|
||||
max=1.0,
|
||||
step=0.01,
|
||||
step=0.001,
|
||||
bind:valueAsNumber=ctrl_x
|
||||
)
|
||||
input(
|
||||
type="range",
|
||||
min=-1.0,
|
||||
max=1.0,
|
||||
step=0.01,
|
||||
step=0.001,
|
||||
bind:valueAsNumber=ctrl_y
|
||||
)
|
||||
input(
|
||||
type="range",
|
||||
max=1.0,
|
||||
step=0.01,
|
||||
step=0.001,
|
||||
bind:valueAsNumber=opacity
|
||||
)
|
||||
input(
|
||||
type="range",
|
||||
max=3.0,
|
||||
step=1.0,
|
||||
bind:valueAsNumber=layer_threshold
|
||||
)
|
||||
}
|
||||
}
|
||||
});
|
||||
|
||||
Loading…
Reference in New Issue
Block a user