74 lines
1.8 KiB
Plaintext
74 lines
1.8 KiB
Plaintext
uniform float2 u_resolution;
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const float EPS = 0.001;
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const int MAX_ITER = 64;
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struct sdQuery {
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float value;
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int obj_id;
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};
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float sdCube(float3 p, float3 b) {
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p = abs(p) - b;
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return length(max(p, 0.0)) + min(max(p.x, max(p.y, p.z)), 0.0);
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}
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float sdSphere(float3 p, float r) {
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return length(p) - r;
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}
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sdQuery sd(float3 p) {
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sdQuery qry;
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qry.value = 100000000.0;
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qry.obj_id = -1;
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<SDF_BLOCK>
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return qry;
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}
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float3 nrm(float3 p) {
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float2 d = float2(EPS, 0.0);
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return normalize(float3(
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sd(p + d.xyy).value - sd(p - d.xyy).value,
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sd(p + d.yxy).value - sd(p - d.yxy).value,
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sd(p + d.yyx).value - sd(p - d.yyx).value
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));
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}
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float4 materialColor(int obj_id) {
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<COLOR_BLOCK>
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return float4(1.0);
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}
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float4 color(float3 p, int obj_id) {
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float3 normal = nrm(p);
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float3 light_dir = normalize(float3(0.5, 0.8, -0.6));
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float light = 0.2 + 0.8 * max(dot(normal, light_dir), 0.0);
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float4 base = materialColor(obj_id);
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return float4(base.rgb * light, base.a);
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}
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float4 march(float3 p, float3 r) {
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sdQuery qry;
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float4 col = float4(0.0);
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for(int i = 0; i < MAX_ITER; ++i) {
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qry = sd(p);
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if(qry.value < EPS){
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col = color(p, qry.obj_id);
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break;
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}
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p += qry.value * r;
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}
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return col;
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}
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half4 main(float2 fragCoord) {
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float2 uv = -2. * (fragCoord / u_resolution - .5) * float2(u_resolution.x / u_resolution.y, 1.);
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float3 c_p = float3(<CAM_POS>);
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float3 c_z = normalize(float3(<CAM_DIR>));
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float3 world_up = abs(c_z.y) > 0.999 ? float3(0., 0., 1.) : float3(0., 1., 0.);
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float3 c_x = normalize(cross(c_z, world_up));
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float3 c_y = normalize(cross(c_x, c_z));
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float3x3 view = float3x3(c_x, c_y, c_z);
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float3 r = normalize(float3(uv, <CAM_FOCUS>));
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return half4(march(c_p, view * r));
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}
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