examples: add an example of march tracing in glsl, first release (#8689)

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#define HANDMADE_MATH_IMPLEMENTATION
#define HANDMADE_MATH_NO_SSE
#include "HandmadeMath.h"
void calc_matrices(void *res, float w, float h, float rx, float ry, float scale){
hmm_mat4 proj = HMM_Perspective(60.0f, w/h, 0.01f, 10.0f);
hmm_mat4 view = HMM_LookAt(HMM_Vec3(0.0f, 0.0f, 6.0f), HMM_Vec3(0.0f, 0.0f, 0.0f), HMM_Vec3(0.0f, 1.0f, 0.0f));
hmm_mat4 view_proj = HMM_MultiplyMat4(proj, view);
//state.rx += 1.0f; state.ry += 2.0f;
hmm_mat4 rxm = HMM_Rotate(rx, HMM_Vec3(1.0f, 0.0f, 0.0f));
hmm_mat4 rym = HMM_Rotate(ry, HMM_Vec3(0.0f, 1.0f, 0.0f));
hmm_mat4 model = HMM_MultiplyMat4(rxm, rym);
hmm_mat4 scale_mx = HMM_Scale(HMM_Vec3(scale, scale, scale));
model = HMM_MultiplyMat4(model, scale_mx);
hmm_mat4 tmp_res = HMM_MultiplyMat4(view_proj, model);
// copy the matrix to V
int i = 0;
float *p = &tmp_res.Elements[0];
while(i < 16){
((float*)(res))[i]= p[i];
i++;
}
}

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//------------------------------------------------------------------------------
// Shader code for texcube-sapp sample.
//
// NOTE: This source file also uses the '#pragma sokol' form of the
// custom tags.
//------------------------------------------------------------------------------
#pragma sokol @ctype mat4 hmm_mat4
#pragma sokol @vs vs
uniform vs_params {
mat4 mvp;
};
in vec4 pos;
in vec4 color0;
in vec2 texcoord0;
out vec4 color;
out vec2 uv;
void main() {
gl_Position = mvp * pos;
color = color0;
uv = texcoord0;
}
#pragma sokol @end
#pragma sokol @fs fs
uniform sampler2D tex;
uniform fs_params {
vec2 iResolution;
vec2 iMouse;
float iTime;
float iFrame;
};
in vec4 color;
in vec2 uv;
out vec4 frag_color;
// change to 0 to 4 to increment the AntiAliasing,
// increase AA will SLOW the rendering!!
#define AA 1
//*********************************************************
// Ray Marching
// original code from: https://www.shadertoy.com/view/Xds3zN
//*********************************************************
// The MIT License
// Copyright © 2013 Inigo Quilez
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// A list of useful distance function to simple primitives. All
// these functions (except for ellipsoid) return an exact
// euclidean distance, meaning they produce a better SDF than
// what you'd get if you were constructing them from boolean
// operations.
//
// More info here:
//
// https://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
//------------------------------------------------------------------
float dot2( in vec2 v ) { return dot(v,v); }
float dot2( in vec3 v ) { return dot(v,v); }
float ndot( in vec2 a, in vec2 b ) { return a.x*b.x - a.y*b.y; }
float sdPlane( vec3 p )
{
return p.y;
}
float sdSphere( vec3 p, float s )
{
return length(p)-s;
}
float sdBox( vec3 p, vec3 b )
{
vec3 d = abs(p) - b;
return min(max(d.x,max(d.y,d.z)),0.0) + length(max(d,0.0));
}
float sdBoundingBox( vec3 p, vec3 b, float e )
{
p = abs(p )-b;
vec3 q = abs(p+e)-e;
return min(min(
length(max(vec3(p.x,q.y,q.z),0.0))+min(max(p.x,max(q.y,q.z)),0.0),
length(max(vec3(q.x,p.y,q.z),0.0))+min(max(q.x,max(p.y,q.z)),0.0)),
length(max(vec3(q.x,q.y,p.z),0.0))+min(max(q.x,max(q.y,p.z)),0.0));
}
float sdEllipsoid( in vec3 p, in vec3 r ) // approximated
{
float k0 = length(p/r);
float k1 = length(p/(r*r));
return k0*(k0-1.0)/k1;
}
float sdTorus( vec3 p, vec2 t )
{
return length( vec2(length(p.xz)-t.x,p.y) )-t.y;
}
float sdCappedTorus(in vec3 p, in vec2 sc, in float ra, in float rb)
{
p.x = abs(p.x);
float k = (sc.y*p.x>sc.x*p.y) ? dot(p.xy,sc) : length(p.xy);
return sqrt( dot(p,p) + ra*ra - 2.0*ra*k ) - rb;
}
float sdHexPrism( vec3 p, vec2 h )
{
vec3 q = abs(p);
const vec3 k = vec3(-0.8660254, 0.5, 0.57735);
p = abs(p);
p.xy -= 2.0*min(dot(k.xy, p.xy), 0.0)*k.xy;
vec2 d = vec2(
length(p.xy - vec2(clamp(p.x, -k.z*h.x, k.z*h.x), h.x))*sign(p.y - h.x),
p.z-h.y );
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}
float sdOctogonPrism( in vec3 p, in float r, float h )
{
const vec3 k = vec3(-0.9238795325, // sqrt(2+sqrt(2))/2
0.3826834323, // sqrt(2-sqrt(2))/2
0.4142135623 ); // sqrt(2)-1
// reflections
p = abs(p);
p.xy -= 2.0*min(dot(vec2( k.x,k.y),p.xy),0.0)*vec2( k.x,k.y);
p.xy -= 2.0*min(dot(vec2(-k.x,k.y),p.xy),0.0)*vec2(-k.x,k.y);
// polygon side
p.xy -= vec2(clamp(p.x, -k.z*r, k.z*r), r);
vec2 d = vec2( length(p.xy)*sign(p.y), p.z-h );
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}
float sdCapsule( vec3 p, vec3 a, vec3 b, float r )
{
vec3 pa = p-a, ba = b-a;
float h = clamp( dot(pa,ba)/dot(ba,ba), 0.0, 1.0 );
return length( pa - ba*h ) - r;
}
float sdRoundCone( in vec3 p, in float r1, float r2, float h )
{
vec2 q = vec2( length(p.xz), p.y );
float b = (r1-r2)/h;
float a = sqrt(1.0-b*b);
float k = dot(q,vec2(-b,a));
if( k < 0.0 ) return length(q) - r1;
if( k > a*h ) return length(q-vec2(0.0,h)) - r2;
return dot(q, vec2(a,b) ) - r1;
}
float sdRoundCone(vec3 p, vec3 a, vec3 b, float r1, float r2)
{
// sampling independent computations (only depend on shape)
vec3 ba = b - a;
float l2 = dot(ba,ba);
float rr = r1 - r2;
float a2 = l2 - rr*rr;
float il2 = 1.0/l2;
// sampling dependant computations
vec3 pa = p - a;
float y = dot(pa,ba);
float z = y - l2;
float x2 = dot2( pa*l2 - ba*y );
float y2 = y*y*l2;
float z2 = z*z*l2;
// single square root!
float k = sign(rr)*rr*rr*x2;
if( sign(z)*a2*z2 > k ) return sqrt(x2 + z2) *il2 - r2;
if( sign(y)*a2*y2 < k ) return sqrt(x2 + y2) *il2 - r1;
return (sqrt(x2*a2*il2)+y*rr)*il2 - r1;
}
float sdTriPrism( vec3 p, vec2 h )
{
const float k = sqrt(3.0);
h.x *= 0.5*k;
p.xy /= h.x;
p.x = abs(p.x) - 1.0;
p.y = p.y + 1.0/k;
if( p.x+k*p.y>0.0 ) p.xy=vec2(p.x-k*p.y,-k*p.x-p.y)/2.0;
p.x -= clamp( p.x, -2.0, 0.0 );
float d1 = length(p.xy)*sign(-p.y)*h.x;
float d2 = abs(p.z)-h.y;
return length(max(vec2(d1,d2),0.0)) + min(max(d1,d2), 0.);
}
// vertical
float sdCylinder( vec3 p, vec2 h )
{
vec2 d = abs(vec2(length(p.xz),p.y)) - h;
return min(max(d.x,d.y),0.0) + length(max(d,0.0));
}
// arbitrary orientation
float sdCylinder(vec3 p, vec3 a, vec3 b, float r)
{
vec3 pa = p - a;
vec3 ba = b - a;
float baba = dot(ba,ba);
float paba = dot(pa,ba);
float x = length(pa*baba-ba*paba) - r*baba;
float y = abs(paba-baba*0.5)-baba*0.5;
float x2 = x*x;
float y2 = y*y*baba;
float d = (max(x,y)<0.0)?-min(x2,y2):(((x>0.0)?x2:0.0)+((y>0.0)?y2:0.0));
return sign(d)*sqrt(abs(d))/baba;
}
// vertical
float sdCone( in vec3 p, in vec2 c, float h )
{
vec2 q = h*vec2(c.x,-c.y)/c.y;
vec2 w = vec2( length(p.xz), p.y );
vec2 a = w - q*clamp( dot(w,q)/dot(q,q), 0.0, 1.0 );
vec2 b = w - q*vec2( clamp( w.x/q.x, 0.0, 1.0 ), 1.0 );
float k = sign( q.y );
float d = min(dot( a, a ),dot(b, b));
float s = max( k*(w.x*q.y-w.y*q.x),k*(w.y-q.y) );
return sqrt(d)*sign(s);
}
float sdCappedCone( in vec3 p, in float h, in float r1, in float r2 )
{
vec2 q = vec2( length(p.xz), p.y );
vec2 k1 = vec2(r2,h);
vec2 k2 = vec2(r2-r1,2.0*h);
vec2 ca = vec2(q.x-min(q.x,(q.y < 0.0)?r1:r2), abs(q.y)-h);
vec2 cb = q - k1 + k2*clamp( dot(k1-q,k2)/dot2(k2), 0.0, 1.0 );
float s = (cb.x < 0.0 && ca.y < 0.0) ? -1.0 : 1.0;
return s*sqrt( min(dot2(ca),dot2(cb)) );
}
float sdCappedCone(vec3 p, vec3 a, vec3 b, float ra, float rb)
{
float rba = rb-ra;
float baba = dot(b-a,b-a);
float papa = dot(p-a,p-a);
float paba = dot(p-a,b-a)/baba;
float x = sqrt( papa - paba*paba*baba );
float cax = max(0.0,x-((paba<0.5)?ra:rb));
float cay = abs(paba-0.5)-0.5;
float k = rba*rba + baba;
float f = clamp( (rba*(x-ra)+paba*baba)/k, 0.0, 1.0 );
float cbx = x-ra - f*rba;
float cby = paba - f;
float s = (cbx < 0.0 && cay < 0.0) ? -1.0 : 1.0;
return s*sqrt( min(cax*cax + cay*cay*baba,
cbx*cbx + cby*cby*baba) );
}
// c is the sin/cos of the desired cone angle
float sdSolidAngle(vec3 pos, vec2 c, float ra)
{
vec2 p = vec2( length(pos.xz), pos.y );
float l = length(p) - ra;
float m = length(p - c*clamp(dot(p,c),0.0,ra) );
return max(l,m*sign(c.y*p.x-c.x*p.y));
}
float sdOctahedron(vec3 p, float s)
{
p = abs(p);
float m = p.x + p.y + p.z - s;
// exact distance
#if 0
vec3 o = min(3.0*p - m, 0.0);
o = max(6.0*p - m*2.0 - o*3.0 + (o.x+o.y+o.z), 0.0);
return length(p - s*o/(o.x+o.y+o.z));
#endif
// exact distance
#if 1
vec3 q;
if( 3.0*p.x < m ) q = p.xyz;
else if( 3.0*p.y < m ) q = p.yzx;
else if( 3.0*p.z < m ) q = p.zxy;
else return m*0.57735027;
float k = clamp(0.5*(q.z-q.y+s),0.0,s);
return length(vec3(q.x,q.y-s+k,q.z-k));
#endif
// bound, not exact
#if 0
return m*0.57735027;
#endif
}
float sdPyramid( in vec3 p, in float h )
{
float m2 = h*h + 0.25;
// symmetry
p.xz = abs(p.xz);
p.xz = (p.z>p.x) ? p.zx : p.xz;
p.xz -= 0.5;
// project into face plane (2D)
vec3 q = vec3( p.z, h*p.y - 0.5*p.x, h*p.x + 0.5*p.y);
float s = max(-q.x,0.0);
float t = clamp( (q.y-0.5*p.z)/(m2+0.25), 0.0, 1.0 );
float a = m2*(q.x+s)*(q.x+s) + q.y*q.y;
float b = m2*(q.x+0.5*t)*(q.x+0.5*t) + (q.y-m2*t)*(q.y-m2*t);
float d2 = min(q.y,-q.x*m2-q.y*0.5) > 0.0 ? 0.0 : min(a,b);
// recover 3D and scale, and add sign
return sqrt( (d2+q.z*q.z)/m2 ) * sign(max(q.z,-p.y));
}
// la,lb=semi axis, h=height, ra=corner
float sdRhombus(vec3 p, float la, float lb, float h, float ra)
{
p = abs(p);
vec2 b = vec2(la,lb);
float f = clamp( (ndot(b,b-2.0*p.xz))/dot(b,b), -1.0, 1.0 );
vec2 q = vec2(length(p.xz-0.5*b*vec2(1.0-f,1.0+f))*sign(p.x*b.y+p.z*b.x-b.x*b.y)-ra, p.y-h);
return min(max(q.x,q.y),0.0) + length(max(q,0.0));
}
//------------------------------------------------------------------
vec2 opU( vec2 d1, vec2 d2 )
{
return (d1.x<d2.x) ? d1 : d2;
}
//------------------------------------------------------------------
#define ZERO (min(int(iFrame),0))
//------------------------------------------------------------------
vec2 map( in vec3 pos )
{
vec2 res = vec2( 1e10, 0.0 );
{
res = opU( res, vec2( sdSphere( pos-vec3(-2.0,0.25, 0.0), 0.25 ), 26.9 ) );
}
// bounding box
if( sdBox( pos-vec3(0.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
{
// more primitives
res = opU( res, vec2( sdBoundingBox( pos-vec3( 0.0,0.25, 0.0), vec3(0.3,0.25,0.2), 0.025 ), 16.9 ) );
res = opU( res, vec2( sdTorus( (pos-vec3( 0.0,0.30, 1.0)).xzy, vec2(0.25,0.05) ), 25.0 ) );
res = opU( res, vec2( sdCone( pos-vec3( 0.0,0.45,-1.0), vec2(0.6,0.8),0.45 ), 55.0 ) );
res = opU( res, vec2( sdCappedCone( pos-vec3( 0.0,0.25,-2.0), 0.25, 0.25, 0.1 ), 13.67 ) );
res = opU( res, vec2( sdSolidAngle( pos-vec3( 0.0,0.00,-3.0), vec2(3,4)/5.0, 0.4 ), 49.13 ) );
}
// bounding box
if( sdBox( pos-vec3(1.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
{
// more primitives
res = opU( res, vec2( sdCappedTorus((pos-vec3( 1.0,0.30, 1.0))*vec3(1,-1,1), vec2(0.866025,-0.5), 0.25, 0.05), 8.5) );
res = opU( res, vec2( sdBox( pos-vec3( 1.0,0.25, 0.0), vec3(0.3,0.25,0.1) ), 3.0 ) );
res = opU( res, vec2( sdCapsule( pos-vec3( 1.0,0.00,-1.0),vec3(-0.1,0.1,-0.1), vec3(0.2,0.4,0.2), 0.1 ), 31.9 ) );
res = opU( res, vec2( sdCylinder( pos-vec3( 1.0,0.25,-2.0), vec2(0.15,0.25) ), 8.0 ) );
res = opU( res, vec2( sdHexPrism( pos-vec3( 1.0,0.2,-3.0), vec2(0.2,0.05) ), 18.4 ) );
}
// bounding box
if( sdBox( pos-vec3(-1.0,0.35,-1.0),vec3(0.35,0.35,2.5))<res.x )
{
// more primitives
res = opU( res, vec2( sdPyramid( pos-vec3(-1.0,-0.6,-3.0), 1.0 ), 13.56 ) );
res = opU( res, vec2( sdOctahedron( pos-vec3(-1.0,0.15,-2.0), 0.35 ), 23.56 ) );
res = opU( res, vec2( sdTriPrism( pos-vec3(-1.0,0.15,-1.0), vec2(0.3,0.05) ),43.5 ) );
res = opU( res, vec2( sdEllipsoid( pos-vec3(-1.0,0.25, 0.0), vec3(0.2, 0.25, 0.05) ), 43.17 ) );
res = opU( res, vec2( sdRhombus( (pos-vec3(-1.0,0.34, 1.0)).xzy, 0.15, 0.25, 0.04, 0.08 ),17.0 ) );
}
// bounding box
if( sdBox( pos-vec3(2.0,0.3,-1.0),vec3(0.35,0.3,2.5) )<res.x )
{
// more primitives
res = opU( res, vec2( sdOctogonPrism(pos-vec3( 2.0,0.2,-3.0), 0.2, 0.05), 51.8 ) );
res = opU( res, vec2( sdCylinder( pos-vec3( 2.0,0.15,-2.0), vec3(0.1,-0.1,0.0), vec3(-0.2,0.35,0.1), 0.08), 31.2 ) );
res = opU( res, vec2( sdCappedCone( pos-vec3( 2.0,0.10,-1.0), vec3(0.1,0.0,0.0), vec3(-0.2,0.40,0.1), 0.15, 0.05), 46.1 ) );
res = opU( res, vec2( sdRoundCone( pos-vec3( 2.0,0.15, 0.0), vec3(0.1,0.0,0.0), vec3(-0.1,0.35,0.1), 0.15, 0.05), 51.7 ) );
res = opU( res, vec2( sdRoundCone( pos-vec3( 2.0,0.20, 1.0), 0.2, 0.1, 0.3 ), 37.0 ) );
}
return res;
}
// http://iquilezles.org/www/articles/boxfunctions/boxfunctions.htm
vec2 iBox( in vec3 ro, in vec3 rd, in vec3 rad )
{
vec3 m = 1.0/rd;
vec3 n = m*ro;
vec3 k = abs(m)*rad;
vec3 t1 = -n - k;
vec3 t2 = -n + k;
return vec2( max( max( t1.x, t1.y ), t1.z ),
min( min( t2.x, t2.y ), t2.z ) );
}
vec2 raycast( in vec3 ro, in vec3 rd )
{
vec2 res = vec2(-1.0,-1.0);
float tmin = 1.0;
float tmax = 20.0;
// raytrace floor plane
float tp1 = (0.0-ro.y)/rd.y;
if( tp1>0.0 )
{
tmax = min( tmax, tp1 );
res = vec2( tp1, 1.0 );
}
//else return res;
// raymarch primitives
vec2 tb = iBox( ro-vec3(0.0,0.4,-0.5), rd, vec3(2.5,0.41,3.0) );
if( tb.x<tb.y && tb.y>0.0 && tb.x<tmax)
{
//return vec2(tb.x,2.0);
tmin = max(tb.x,tmin);
tmax = min(tb.y,tmax);
float t = tmin;
for( int i=0; i<70 && t<tmax; i++ )
{
vec2 h = map( ro+rd*t );
if( abs(h.x)<(0.0001*t) )
{
res = vec2(t,h.y);
break;
}
t += h.x;
}
}
return res;
}
// http://iquilezles.org/www/articles/rmshadows/rmshadows.htm
float calcSoftshadow( in vec3 ro, in vec3 rd, in float mint, in float tmax )
{
// bounding volume
float tp = (0.8-ro.y)/rd.y; if( tp>0.0 ) tmax = min( tmax, tp );
float res = 1.0;
float t = mint;
for( int i=ZERO; i<24; i++ )
{
float h = map( ro + rd*t ).x;
float s = clamp(8.0*h/t,0.0,1.0);
res = min( res, s*s*(3.0-2.0*s) );
t += clamp( h, 0.02, 0.2 );
if( res<0.004 || t>tmax ) break;
}
return clamp( res, 0.0, 1.0 );
}
// http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm
vec3 calcNormal( in vec3 pos )
{
#if 0
vec2 e = vec2(1.0,-1.0)*0.5773*0.0005;
return normalize( e.xyy*map( pos + e.xyy ).x +
e.yyx*map( pos + e.yyx ).x +
e.yxy*map( pos + e.yxy ).x +
e.xxx*map( pos + e.xxx ).x );
#else
// inspired by tdhooper and klems - a way to prevent the compiler from inlining map() 4 times
vec3 n = vec3(0.0);
for( int i=ZERO; i<4; i++ )
{
vec3 e = 0.5773*(2.0*vec3((((i+3)>>1)&1),((i>>1)&1),(i&1))-1.0);
n += e*map(pos+0.0005*e).x;
//if( n.x+n.y+n.z>100.0 ) break;
}
return normalize(n);
#endif
}
float calcAO( in vec3 pos, in vec3 nor )
{
float occ = 0.0;
float sca = 1.0;
for( int i=ZERO; i<5; i++ )
{
float h = 0.01 + 0.12*float(i)/4.0;
float d = map( pos + h*nor ).x;
occ += (h-d)*sca;
sca *= 0.95;
if( occ>0.35 ) break;
}
return clamp( 1.0 - 3.0*occ, 0.0, 1.0 ) * (0.5+0.5*nor.y);
}
// http://iquilezles.org/www/articles/checkerfiltering/checkerfiltering.htm
float checkersGradBox( in vec2 p, in vec2 dpdx, in vec2 dpdy )
{
// filter kernel
vec2 w = abs(dpdx)+abs(dpdy) + 0.001;
// analytical integral (box filter)
vec2 i = 2.0*(abs(fract((p-0.5*w)*0.5)-0.5)-abs(fract((p+0.5*w)*0.5)-0.5))/w;
// xor pattern
return 0.5 - 0.5*i.x*i.y;
}
vec3 render( in vec3 ro, in vec3 rd, in vec3 rdx, in vec3 rdy )
{
// background
vec3 col = vec3(0.7, 0.7, 0.9) - max(rd.y,0.0)*0.3;
// raycast scene
vec2 res = raycast(ro,rd);
float t = res.x;
float m = res.y;
if( m>-0.5 )
{
vec3 pos = ro + t*rd;
vec3 nor = (m<1.5) ? vec3(0.0,1.0,0.0) : calcNormal( pos );
vec3 ref = reflect( rd, nor );
// material
col = 0.2 + 0.2*sin( m*2.0 + vec3(0.0,1.0,2.0) );
float ks = 1.0;
if( m<1.5 )
{
// project pixel footprint into the plane
vec3 dpdx = ro.y*(rd/rd.y-rdx/rdx.y);
vec3 dpdy = ro.y*(rd/rd.y-rdy/rdy.y);
float f = checkersGradBox( 3.0*pos.xz, 3.0*dpdx.xz, 3.0*dpdy.xz );
col = 0.15 + f*vec3(0.05);
ks = 0.4;
}
// lighting
float occ = calcAO( pos, nor );
vec3 lin = vec3(0.0);
// sun
{
vec3 lig = normalize( vec3(-0.5, 0.4, -0.6) );
vec3 hal = normalize( lig-rd );
float dif = clamp( dot( nor, lig ), 0.0, 1.0 );
//if( dif>0.0001 )
dif *= calcSoftshadow( pos, lig, 0.02, 2.5 );
float spe = pow( clamp( dot( nor, hal ), 0.0, 1.0 ),16.0);
spe *= dif;
spe *= 0.04+0.96*pow(clamp(1.0-dot(hal,lig),0.0,1.0),5.0);
lin += col*2.20*dif*vec3(1.30,1.00,0.70);
lin += 5.00*spe*vec3(1.30,1.00,0.70)*ks;
}
// sky
{
float dif = sqrt(clamp( 0.5+0.5*nor.y, 0.0, 1.0 ));
dif *= occ;
float spe = smoothstep( -0.2, 0.2, ref.y );
spe *= dif;
spe *= 0.04+0.96*pow(clamp(1.0+dot(nor,rd),0.0,1.0), 5.0 );
//if( spe>0.001 )
spe *= calcSoftshadow( pos, ref, 0.02, 2.5 );
lin += col*0.60*dif*vec3(0.40,0.60,1.15);
lin += 2.00*spe*vec3(0.40,0.60,1.30)*ks;
}
// back
{
float dif = clamp( dot( nor, normalize(vec3(0.5,0.0,0.6))), 0.0, 1.0 )*clamp( 1.0-pos.y,0.0,1.0);
dif *= occ;
lin += col*0.55*dif*vec3(0.25,0.25,0.25);
}
// sss
{
float dif = pow(clamp(1.0+dot(nor,rd),0.0,1.0),2.0);
dif *= occ;
lin += col*0.25*dif*vec3(1.00,1.00,1.00);
}
col = lin;
col = mix( col, vec3(0.7,0.7,0.9), 1.0-exp( -0.0001*t*t*t ) );
}
return vec3( clamp(col,0.0,1.0) );
}
mat3 setCamera( in vec3 ro, in vec3 ta, float cr )
{
vec3 cw = normalize(ta-ro);
vec3 cp = vec3(sin(cr), cos(cr),0.0);
vec3 cu = normalize( cross(cw,cp) );
vec3 cv = ( cross(cu,cw) );
return mat3( cu, cv, cw );
}
vec4 mainImage( vec2 fragCoord )
{
vec2 mo = iMouse.xy/iResolution.xy;
float time = 32.0 + iTime*1.5;
// camera
vec3 ta = vec3( 0.5, -0.5, -0.6 );
vec3 ro = ta + vec3( 4.5*cos(0.1*time + 7.0*mo.x), 1.3 + 2.0*mo.y, 4.5*sin(0.1*time + 7.0*mo.x) );
// camera-to-world transformation
mat3 ca = setCamera( ro, ta, 0.0 );
vec3 tot = vec3(0.0);
#if AA>1
for( int m=ZERO; m<AA; m++ )
for( int n=ZERO; n<AA; n++ )
{
// pixel coordinates
vec2 o = vec2(float(m),float(n)) / float(AA) - 0.5;
vec2 p = (2.0*(fragCoord+o)-iResolution.xy)/iResolution.y;
#else
vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
#endif
// focal length
const float fl = 2.5;
// ray direction
vec3 rd = ca * normalize( vec3(p,fl) );
// ray differentials
vec2 px = (2.0*(fragCoord+vec2(1.0,0.0))-iResolution.xy)/iResolution.y;
vec2 py = (2.0*(fragCoord+vec2(0.0,1.0))-iResolution.xy)/iResolution.y;
vec3 rdx = ca * normalize( vec3(px,fl) );
vec3 rdy = ca * normalize( vec3(py,fl) );
// render
vec3 col = render( ro, rd, rdx, rdy );
// gain
// col = col*3.0/(2.5+col);
// gamma
col = pow( col, vec3(0.4545) );
tot += col;
#if AA>1
}
tot /= float(AA*AA);
#endif
//fragColor = vec4( tot, 1.0 );
return vec4( tot, 1.0 );
}
//*********************************************************
// END Ray Marching
//*********************************************************
void main() {
vec4 c = color;
vec4 txt = texture(tex, uv);
c = txt * c;
vec2 uv1 = uv * iResolution;
vec4 col_ray = mainImage(uv1);
// use this to mix the chessboart texture with the ray marching
//frag_color = clamp(c*iMouse.y/512.0,0.0,1.0) * col_ray ;
frag_color = c*0.00001 + col_ray ;
}
#pragma sokol @end
#pragma sokol @program rt vs fs

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/**********************************************************************
*
* Sokol 3d cube demo
*
* Copyright (c) 2021 Dario Deledda. All rights reserved.
* Use of this source code is governed by an MIT license
* that can be found in the LICENSE file.
*
* HOW TO COMPILE SHADERS:
* - donwload sokol shader tool from: https://github.com/floooh/sokol-tools/blob/master/docs/sokol-shdc.md
* - compile shader with:
* linux : sokol-shdc --input rt_glsl.glsl --output rt_glsl.h --slang glsl330
* windows: sokol-shdc.exe --input rt_glsl.glsl --output rt_glsl.h --slang glsl330
*
* --slang parameter can be:
* - glsl330: desktop GL
* - glsl100: GLES2 / WebGL
* - glsl300es: GLES3 / WebGL2
* - hlsl4: D3D11
* - hlsl5: D3D11
* - metal_macos: Metal on macOS
* - metal_ios: Metal on iOS device
* - metal_sim: Metal on iOS simulator
* - wgpu: WebGPU
*
* you can have multiple platforms at the same time passing parameters like this: --slang glsl330:hlsl5:metal_macos
* for further infos have a look at the sokol shader tool docs.
*
* TODO:
* - frame counter
**********************************************************************/
import gg
import gx
//import math
import sokol.sapp
import sokol.gfx
import sokol.sgl
import time
const (
win_width = 800
win_height = 800
bg_color = gx.white
)
struct App {
mut:
gg &gg.Context
texture C.sg_image
init_flag bool
frame_count int
mouse_x int = -1
mouse_y int = -1
// glsl
cube_pip_glsl C.sg_pipeline
cube_bind C.sg_bindings
// time
ticks i64
}
/******************************************************************************
*
* GLSL Include and functions
*
******************************************************************************/
#flag -I @VROOT/.
#include "HandmadeMath.h"
#include "rt_glsl.h"
#include "default_include.h"
fn C.rt_shader_desc() &C.sg_shader_desc
fn C.calc_matrices(res voidptr,w f32, h f32, rx f32, ry f32, scale f32)
/******************************************************************************
*
* Texture functions
*
******************************************************************************/
fn create_texture(w int, h int, buf byteptr) C.sg_image{
sz := w * h * 4
mut img_desc := C.sg_image_desc{
width: w
height: h
num_mipmaps: 0
min_filter: .linear
mag_filter: .linear
//usage: .dynamic
wrap_u: .clamp_to_edge
wrap_v: .clamp_to_edge
label: &byte(0)
d3d11_texture: 0
}
// comment if .dynamic is enabled
img_desc.content.subimage[0][0] = C.sg_subimage_content{
ptr: buf
size: sz
}
sg_img := C.sg_make_image(&img_desc)
return sg_img
}
fn destroy_texture(sg_img C.sg_image){
C.sg_destroy_image(sg_img)
}
// Use only if usage: .dynamic is enabled
fn update_text_texture(sg_img C.sg_image, w int, h int, buf byteptr){
sz := w * h * 4
mut tmp_sbc := C.sg_image_content{}
tmp_sbc.subimage[0][0] = C.sg_subimage_content {
ptr: buf
size: sz
}
C.sg_update_image(sg_img, &tmp_sbc)
}
/******************************************************************************
*
* Draw functions
*
******************************************************************************/
/*
Cube vertex buffer with packed vertex formats for color and texture coords.
Note that a vertex format which must be portable across all
backends must only use the normalized integer formats
(BYTE4N, UBYTE4N, SHORT2N, SHORT4N), which can be converted
to floating point formats in the vertex shader inputs.
The reason is that D3D11 cannot convert from non-normalized
formats to floating point inputs (only to integer inputs),
and WebGL2 / GLES2 don't support integer vertex shader inputs.
*/
struct Vertex_t {
x f32
y f32
z f32
color u32
//u u16 // for compatibility with D3D11
//v u16 // for compatibility with D3D11
u f32
v f32
}
fn init_cube_glsl(mut app App) {
/* cube vertex buffer */
//d := u16(32767) // for compatibility with D3D11, 32767 stand for 1
d := f32(1.0)
c := u32(0xFFFFFF_FF) // color RGBA8
vertices := [
Vertex_t{-1.0, -1.0, -1.0, c, 0, 0},
Vertex_t{ 1.0, -1.0, -1.0, c, d, 0},
Vertex_t{ 1.0, 1.0, -1.0, c, d, d},
Vertex_t{-1.0, 1.0, -1.0, c, 0, d},
Vertex_t{-1.0, -1.0, 1.0, c, 0, 0},
Vertex_t{ 1.0, -1.0, 1.0, c, d, 0},
Vertex_t{ 1.0, 1.0, 1.0, c, d, d},
Vertex_t{-1.0, 1.0, 1.0, c, 0, d},
Vertex_t{-1.0, -1.0, -1.0, c, 0, 0},
Vertex_t{-1.0, 1.0, -1.0, c, d, 0},
Vertex_t{-1.0, 1.0, 1.0, c, d, d},
Vertex_t{-1.0, -1.0, 1.0, c, 0, d},
Vertex_t{ 1.0, -1.0, -1.0, c, 0, 0},
Vertex_t{ 1.0, 1.0, -1.0, c, d, 0},
Vertex_t{ 1.0, 1.0, 1.0, c, d, d},
Vertex_t{ 1.0, -1.0, 1.0, c, 0, d},
Vertex_t{-1.0, -1.0, -1.0, c, 0, 0},
Vertex_t{-1.0, -1.0, 1.0, c, d, 0},
Vertex_t{ 1.0, -1.0, 1.0, c, d, d},
Vertex_t{ 1.0, -1.0, -1.0, c, 0, d},
Vertex_t{-1.0, 1.0, -1.0, c, 0, 0},
Vertex_t{-1.0, 1.0, 1.0, c, d, 0},
Vertex_t{ 1.0, 1.0, 1.0, c, d, d},
Vertex_t{ 1.0, 1.0, -1.0, c, 0, d},
]
mut vert_buffer_desc := C.sg_buffer_desc{}
unsafe {C.memset(&vert_buffer_desc, 0, sizeof(vert_buffer_desc))}
vert_buffer_desc.size = vertices.len * int(sizeof(Vertex_t))
vert_buffer_desc.content = byteptr(vertices.data)
vert_buffer_desc.@type = .vertexbuffer
vert_buffer_desc.label = "cube-vertices".str
vbuf := gfx.make_buffer(&vert_buffer_desc)
/* create an index buffer for the cube */
indices := [
u16(0), 1, 2, 0, 2, 3,
6, 5, 4, 7, 6, 4,
8, 9, 10, 8, 10, 11,
14, 13, 12, 15, 14, 12,
16, 17, 18, 16, 18, 19,
22, 21, 20, 23, 22, 20
]
mut index_buffer_desc := C.sg_buffer_desc{}
unsafe {C.memset(&index_buffer_desc, 0, sizeof(index_buffer_desc))}
index_buffer_desc.size = indices.len * int(sizeof(u16))
index_buffer_desc.content = byteptr(indices.data)
index_buffer_desc.@type = .indexbuffer
index_buffer_desc.label = "cube-indices".str
ibuf := gfx.make_buffer(&index_buffer_desc)
/* create shader */
shader := gfx.make_shader(C.rt_shader_desc())
mut pipdesc := C.sg_pipeline_desc{}
unsafe {C.memset(&pipdesc, 0, sizeof(pipdesc))}
pipdesc.layout.buffers[0].stride = int(sizeof(Vertex_t))
// the constants [C.ATTR_vs_pos, C.ATTR_vs_color0, C.ATTR_vs_texcoord0] are generated by sokol-shdc
pipdesc.layout.attrs[C.ATTR_vs_pos ].format = .float3 // x,y,z as f32
pipdesc.layout.attrs[C.ATTR_vs_color0 ].format = .ubyte4n // color as u32
pipdesc.layout.attrs[C.ATTR_vs_texcoord0].format = .float2 // u,v as f32
//pipdesc.layout.attrs[C.ATTR_vs_texcoord0].format = .short2n // u,v as u16
pipdesc.shader = shader
pipdesc.index_type = .uint16
pipdesc.depth_stencil = C.sg_depth_stencil_state{
depth_write_enabled: true
depth_compare_func : gfx.CompareFunc(C.SG_COMPAREFUNC_LESS_EQUAL)
}
pipdesc.rasterizer = C.sg_rasterizer_state {
cull_mode: .back
}
pipdesc.label = "glsl_shader pipeline".str
app.cube_bind.vertex_buffers[0] = vbuf
app.cube_bind.index_buffer = ibuf
app.cube_bind.fs_images[C.SLOT_tex] = app.texture
app.cube_pip_glsl = gfx.make_pipeline(&pipdesc)
println("GLSL init DONE!")
}
fn draw_cube_glsl(app App){
if app.init_flag == false {
return
}
ws := gg.window_size()
ratio := f32(ws.width) / ws.height
dw := f32(ws.width / 2)
dh := f32(ws.height / 2)
mut res := [f32(0),0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0]!
// use the following commented lines to rotate the 3d glsl cube
// rot := [f32(app.mouse_y), f32(app.mouse_x)]
// C.calc_matrices( voidptr(&res), dw, dh, rot[0], rot[1] ,2.3)
C.calc_matrices( voidptr(&res), dw, dh, 0, 0 ,2.3)
gfx.apply_viewport(0, 0, ws.width, ws.height, true)
// apply the pipline and bindings
gfx.apply_pipeline(app.cube_pip_glsl)
gfx.apply_bindings(app.cube_bind)
//***************
// Uniforms
//***************
// passing the view matrix as uniform
// res is a 4x4 matrix of f32 thus: 4*16 byte of size
gfx.apply_uniforms(C.SG_SHADERSTAGE_VS, C.SLOT_vs_params, &res, int(sizeof(res)) )
// fragment shader uniforms
time_ticks := f32(time.ticks() - app.ticks) / 1000
mut tmp_fs_params := [
f32(ws.width), ws.height * ratio, // x,y resolution to pass to FS
app.mouse_x, // mouse x
ws.height - app.mouse_y*2, // mouse y scaled
time_ticks, // time as f32
app.frame_count, // frame count
0,0 // padding bytes , see "fs_params" struct paddings in rt_glsl.h
]!
gfx.apply_uniforms(C.SG_SHADERSTAGE_FS, C.SLOT_fs_params, &tmp_fs_params, int(sizeof(tmp_fs_params)))
// 3 vertices for triangle * 2 triangles per face * 6 faces = 36 vertices to draw
gfx.draw(0, (3 * 2) * 6, 1)
gfx.end_pass()
gfx.commit()
}
fn frame(mut app App) {
ws := gg.window_size()
// clear
mut color_action := C.sg_color_attachment_action{
action: gfx.Action(C.SG_ACTION_CLEAR)
}
color_action.val[0] = 0
color_action.val[1] = 0
color_action.val[2] = 0
color_action.val[3] = 1.0
mut pass_action := C.sg_pass_action{}
pass_action.colors[0] = color_action
gfx.begin_default_pass(&pass_action, ws.width, ws.height)
// glsl cube
draw_cube_glsl(app)
app.frame_count++
}
/******************************************************************************
*
* Init / Cleanup
*
******************************************************************************/
fn my_init(mut app App) {
// set max vertices,
// for a large number of the same type of object it is better use the instances!!
desc := sapp.create_desc()
gfx.setup(&desc)
sgl_desc := C.sgl_desc_t{
max_vertices: 50 * 65536
}
sgl.setup(&sgl_desc)
// create chessboard texture 256*256 RGBA
w := 256
h := 256
sz := w * h * 4
tmp_txt := malloc(sz)
mut i := 0
for i < sz {
unsafe {
y := (i >> 0x8) >> 5 // 8 cell
x := (i & 0xFF) >> 5 // 8 cell
// upper left corner
if x==0 && y==0 {
tmp_txt[i ] = byte(0xFF)
tmp_txt[i+1] = byte(0)
tmp_txt[i+2] = byte(0)
tmp_txt[i+3] = byte(0xFF)
}
// low right corner
else if x==7 && y==7 {
tmp_txt[i ] = byte(0)
tmp_txt[i+1] = byte(0xFF)
tmp_txt[i+2] = byte(0)
tmp_txt[i+3] = byte(0xFF)
} else {
col := if ((x+y) & 1) == 1 {0xFF} else {128}
tmp_txt[i ] = byte(col) // red
tmp_txt[i+1] = byte(col) // green
tmp_txt[i+2] = byte(col) // blue
tmp_txt[i+3] = byte(0xFF) // alpha
}
i += 4
}
}
app.texture = create_texture(w, h, tmp_txt)
free(tmp_txt)
// glsl
init_cube_glsl(mut app)
app.init_flag = true
}
fn cleanup(mut app App) {
gfx.shutdown()
}
/******************************************************************************
*
* event
*
******************************************************************************/
fn my_event_manager(mut ev sapp.Event, mut app App) {
if ev.typ == .mouse_move {
app.mouse_x = int(ev.mouse_x)
app.mouse_y = int(ev.mouse_y)
}
if ev.typ == .touches_began || ev.typ == .touches_moved {
if ev.num_touches > 0 {
touch_point := ev.touches[0]
app.mouse_x = int(touch_point.pos_x)
app.mouse_y = int(touch_point.pos_y)
}
}
}
/******************************************************************************
*
* Main
*
******************************************************************************/
[console]
fn main(){
// App init
mut app := &App{
gg: 0
}
app.gg = gg.new_context({
width: win_width
height: win_height
use_ortho: true // This is needed for 2D drawing
create_window: true
window_title: '3D Ray Marching Cube'
user_data: app
bg_color: bg_color
frame_fn: frame
init_fn: my_init
cleanup_fn: cleanup
event_fn: my_event_manager
})
app.ticks = time.ticks()
app.gg.run()
}

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