engine/bin/data/shaders/raytracing.comp.glsl
2020-07-23 00:00:00 -05:00

408 lines
12 KiB
GLSL

#version 450
layout (local_size_x = 32, local_size_y = 32) in;
layout (binding = 0, rgba8) uniform writeonly image2D resultImage;
#define EPSILON 0.00001
#define MAXLEN 1000.0
#define SHADOW 0.5
#define RAYBOUNCES 4
#define REFLECTIONS true
#define REFLECTIONSTRENGTH 0.4
#define REFLECTIONFALLOFF 0.5
#define UINT32_MAX 0xFFFFFFFF
#define TREE_SIZE 8
#define TREE_STACK 32
#define PRIMITIVE_TYPE_EMPTY UINT32_MAX
#define PRIMITIVE_TYPE_CUBE 1
#define PRIMITIVE_TYPE_LEAF 2
#define PRIMITIVE_TYPE_TREE 3
#define PRIMITIVE_TYPE_ROOT 4
struct Camera {
vec3 position;
mat4 view;
float aspectRatio;
};
struct StartEnd {
uint start;
uint end;
};
struct Cube {
vec4 position;
uint type;
// uint _padding[3];
};
struct Tree {
vec4 position;
uint type;
uint children[TREE_SIZE];
// uint _padding[3];
};
struct Light {
vec3 position;
vec3 color;
};
layout (binding = 1) uniform UBO {
Camera camera;
StartEnd cubes;
StartEnd lights;
uint root;
} ubo;
layout (std140, binding = 2) buffer Cubes {
Cube cubes[ ];
};
layout (std430, binding = 3) buffer Trees {
Tree trees[ ];
};
layout (std140, binding = 4) buffer Lights {
Light lights[ ];
};
layout (binding = 5) uniform sampler2D samplerTexture;
// Lighting =========================================================
void reflectRay(inout vec3 rayD, in vec3 mormal) {
rayD = rayD + 2.0 * -dot(mormal, rayD) * mormal;
}
float lightDiffuse(vec3 normal, vec3 lightDir) {
return clamp(dot(normal, lightDir), 0.1, 1.0);
}
float lightSpecular(vec3 normal, vec3 lightDir, float specularFactor) {
vec3 viewVec = normalize(ubo.camera.position);
vec3 halfVec = normalize(lightDir + viewVec);
return pow(clamp(dot(normal, halfVec), 0.0, 1.0), specularFactor);
}
// Cube ===========================================================
float cubeIntersect(vec3 rayO, vec3 rayD, vec3 rayDRecip, Cube cube) {
float t[10];
t[1] = ( cube.position.x - cube.position.w - rayO.x) * rayDRecip.x;
t[2] = ( cube.position.x + cube.position.w - rayO.x) * rayDRecip.x;
t[3] = ( cube.position.y - cube.position.w - rayO.y) * rayDRecip.y;
t[4] = ( cube.position.y + cube.position.w - rayO.y) * rayDRecip.y;
t[5] = ( cube.position.z - cube.position.w - rayO.z) * rayDRecip.z;
t[6] = ( cube.position.z + cube.position.w - rayO.z) * rayDRecip.z;
t[7] = max(max(min(t[1], t[2]), min(t[3], t[4])), min(t[5], t[6]));
t[8] = min(min(max(t[1], t[2]), max(t[3], t[4])), max(t[5], t[6]));
t[9] = (t[8] < 0 || t[7] > t[8]) ? 0.0 : t[7];
return t[9];
}
uint intersect(in vec3 rayO, in vec3 rayD, inout float resT, uint start, uint end) {
uint id = UINT32_MAX;
vec3 rayDRecip = 1.0f / rayD;
for (uint i = start; i < end && i < ubo.cubes.end && i < cubes.length(); i++) {
Cube cube = cubes[i];
if ( cube.type == PRIMITIVE_TYPE_EMPTY ) continue;
float tcube = cubeIntersect(rayO, rayD, rayDRecip, cube);
if ((tcube > EPSILON) && (tcube < resT)) {
id = i;
resT = tcube;
}
}
return id;
}
// Tree ===========================================================
float treeIntersect( in vec3 rayO, in vec3 rayD, in vec3 rayDRecip, Tree tree ) {
Cube treecube;
treecube.type = tree.type;
treecube.position = tree.position;
float t = cubeIntersect( rayO, rayD, rayDRecip, treecube );
return t;
}
struct StackIterator {
uint tree;
uint child;
};
struct Stack {
int pointer;
StackIterator container[TREE_STACK];
};
Stack stack;
StackIterator popStack( ) {
StackIterator top = stack.container[stack.pointer];
stack.container[stack.pointer--] = StackIterator( UINT32_MAX, UINT32_MAX );
return top;
}
void pushStack( StackIterator item ) {
stack.container[++stack.pointer] = item;
}
uint intersectTreecursive( in vec3 rayO, in vec3 rayD, in vec3 rayDRecip, inout float resT, uint root ) {
uint id = UINT32_MAX;
if ( root == UINT32_MAX ) return id;
// set up stack
stack.pointer = -1;
for ( uint i = 0; i < TREE_STACK; ++i ) stack.container[i] = StackIterator( UINT32_MAX, UINT32_MAX );
pushStack(StackIterator( root, UINT32_MAX ));
while ( true ) {
StackIterator it = popStack();
// end of stack
if ( it.tree == UINT32_MAX ) break;
Tree tree = trees[it.tree];
// invalid tree
if ( tree.type == PRIMITIVE_TYPE_EMPTY ) break;
// new tree, parse collision
if ( it.child == UINT32_MAX ) {
float t = treeIntersect( rayO, rayD, rayDRecip, tree );
// bad intersection with this tree, continue with next iteration
if ( t <= EPSILON || t >= resT ) continue;
// push back with new stack
it.child = 0;
pushStack( it );
// continue with next iteration
continue;
} else if ( it.child >= TREE_SIZE ) {
// no new children, continue with next iteration
continue;
} else {
// is leaf
if ( tree.type == PRIMITIVE_TYPE_LEAF ) {
// check children for a match
for ( uint i = 0; i < TREE_SIZE; ++i ) {
uint branchId = tree.children[i];
// unallocated, skip
if ( branchId == UINT32_MAX ) continue;
Cube primitive = cubes[branchId];
if ( primitive.type == PRIMITIVE_TYPE_EMPTY ) continue;
float t = cubeIntersect( rayO, rayD, rayDRecip, primitive );
// branch intersects with ray, set as new parent
if ( (t <= EPSILON) || (t >= resT) ) continue;
id = branchId;
resT = t;
}
// continue with next iteration
continue;
}
// parse children
uint branchId = tree.children[it.child++];
// add new iterator to the stack
pushStack( it );
// unused child, continue with next iteration
if ( branchId == UINT32_MAX ) continue;
// tree branch, push to stack
// the first if block will check its collision
it.tree = branchId;
it.child = UINT32_MAX;
pushStack( it );
continue;
}
}
return id;
}
uint intersectTree( in vec3 rayO, in vec3 rayD, in vec3 rayDRecip, inout float resT ) {
uint id = UINT32_MAX;
// traverse the tree branches to the leaf
uint index = 0;
while ( true ) {
Tree tree = trees[index++];
if ( tree.type == PRIMITIVE_TYPE_EMPTY ) break;
if ( tree.type != PRIMITIVE_TYPE_LEAF ) continue;
float tcube = treeIntersect( rayO, rayD, rayDRecip, tree );
// ray fails collision with parent tree
if ( (tcube <= EPSILON) || (tcube >= resT) ) continue;
// ray intersects with parent tree, check children branches
for ( uint i = 0; i < TREE_SIZE; ++i ) {
uint branchId = tree.children[i];
// unallocated, skip
if ( branchId == UINT32_MAX ) continue;
Cube primitive = cubes[branchId];
if ( primitive.type == PRIMITIVE_TYPE_EMPTY ) continue;
tcube = cubeIntersect( rayO, rayD, rayDRecip, primitive );
// branch intersects with ray, set as new parent
if ( (tcube <= EPSILON) || (tcube >= resT) ) continue;
id = branchId;
resT = tcube;
}
}
return id;
}
float calcShadow(in vec3 rayO, in vec3 rayD, in uint objectId, inout float t, uint start, uint end) {
vec3 rayDRecip = 1.0f / rayD;
for (uint i = ubo.cubes.start; i < ubo.cubes.end && i < cubes.length(); i++) {
if (i == objectId) continue;
float tCube = cubeIntersect(rayO, rayD, rayDRecip, cubes[i]);
if ((tCube > EPSILON) && (tCube < t)) {
t = tCube;
return SHADOW;
}
}
return 1.0;
}
float calcShadowTree(in vec3 rayO, in vec3 rayD, in vec3 rayDRecip, in uint objectId, inout float t){
// traverse the tree branches to the leaf
uint index = 0;
while ( true ) {
Tree tree = trees[index++];
if ( tree.type == PRIMITIVE_TYPE_EMPTY ) break;
if ( tree.type != PRIMITIVE_TYPE_LEAF ) continue;
float tcube = treeIntersect( rayO, rayD, rayDRecip, tree );
// ray fails collision with parent tree
if ( (tcube <= EPSILON) || (tcube >= t) ) continue;
// ray intersects with parent tree, check children branches
for ( uint i = 0; i < TREE_SIZE; ++i ) {
uint branchId = tree.children[i];
// unallocated, skip
if ( branchId == UINT32_MAX ) continue;
Cube primitive = cubes[branchId];
if ( primitive.type == PRIMITIVE_TYPE_EMPTY ) continue;
if ( branchId == objectId ) continue;
tcube = cubeIntersect( rayO, rayD, rayDRecip, primitive );
// branch intersects with ray, set as new parent
if ( (tcube <= EPSILON) || (tcube >= t) ) continue;
t = tcube;
return SHADOW;
}
}
return 1.0;
}
vec3 fog(in float t, in vec3 color) {
return mix(color, vec3(0, 0, 0), clamp(sqrt(t*t)/20.0, 0.0, 1.0));
}
vec3 renderScene(inout vec3 rayO, inout vec3 rayD, inout uint id) {
float t = MAXLEN;
vec3 rayDRecip = 1.0f / rayD;
// Get intersected object ID
uint objectID = intersect(rayO, rayD, t, ubo.cubes.start, ubo.cubes.end );
// uint objectID = intersectTree( rayO, rayD, rayDRecip, t );
// uint objectID = intersectTreecursive( rayO, rayD, rayDRecip, t, ubo.root );
vec3 color = vec3(0.0);
if ( objectID == UINT32_MAX ) return color;
vec3 pos = rayO + t * rayD;
vec3 normal;
// Cubes
if ( id == UINT32_MAX ) return color;
id = objectID;
// Hit Data
{
Cube cube = cubes[objectID];
vec2 mappedUv = vec2(0, 0); {
float min_distance = MAXLEN;
vec3 point = cube.position.xyz - pos;
float distance = abs(cube.position.w - abs(point.x));
if (distance < min_distance) {
min_distance = distance;
normal = vec3(-1, 0, 0);
if ( cube.position.w + point.x <= EPSILON ) normal *= -1;
mappedUv.x = point.y - cube.position.y;
mappedUv.y = point.z - cube.position.z;
}
distance = abs(cube.position.w - abs(point.y));
if (distance < min_distance) {
min_distance = distance;
normal = vec3(0, -1, 0);
if ( cube.position.w + point.y <= EPSILON ) normal *= -1;
mappedUv.x = point.x - cube.position.x;
mappedUv.y = point.z - cube.position.z;
}
distance = abs(cube.position.w - abs(point.z));
if (distance < min_distance) {
min_distance = distance;
normal = vec3(0, 0, -1);
if ( cube.position.w + point.z <= EPSILON ) normal *= -1;
mappedUv.x = point.x - cube.position.x;
mappedUv.y = point.y - cube.position.y;
}
mappedUv -= 2.0f / 4.0f;
mappedUv *= 1.0f / 4.0f;
mappedUv.x = mod(mappedUv.x, 1.0f / 4.0f);
mappedUv.y = mod(mappedUv.y, 1.0f / 4.0f);
}
vec3 textureMapped = texture(samplerTexture, mappedUv).rgb;
color = textureMapped;
}
// Lighting
{
int di = 0;
vec4 diffuses[256];
for ( int j = 0; j < lights.length(); ++j ) {
Light light = lights[j];
if ( light.color.r <= EPSILON && light.color.g <= EPSILON && light.color.b <= EPSILON ) continue;
vec3 lightVec = normalize(light.position - pos);
float diffuse = lightDiffuse(normal, lightVec);
float specular = lightSpecular(normal, lightVec, 2000.0f);
diffuses[di].x = length(light.position - pos);
diffuses[di].gba = diffuse * light.color + specular;
++di;
}
vec4 a = vec4(MAXLEN, vec3(1.0));
vec4 b = vec4(MAXLEN, vec3(1.0));
vec4 c = vec4(MAXLEN, vec3(1.0));
for ( int j = 0; j < lights.length(); ++j ) {
vec4 current = diffuses[j];
if ( current.y <= EPSILON ) continue;
// use slot a
if ( current.x < a.x ) {
c = b;
b = a;
a = current;
} else if ( current.x < b.x ) {
c = b;
b = current;
} else if ( current.x < c.x ) {
c = current;
}
}
vec3 avg = (a.gba * 0.5 + b.gba * 0.3 + c.gba * 0.2);
color *= avg;
}
// Shadows
{
vec3 lightVec = vec3(0, 4, 0) - pos;
t = length(lightVec);
color *= calcShadow(pos, lightVec, id, t, ubo.cubes.start, ubo.cubes.end);
// color *= calcShadowTree(pos, lightVec, rayDRecip, id, t);
}
// Fog
// color = fog(t, color);
// Reflect ray for next render pass
reflectRay(rayD, normal);
rayO = pos;
return color;
}
void main() {
ivec2 dim = imageSize(resultImage);
vec2 uv = vec2(gl_GlobalInvocationID.xy) / dim;
vec3 rayO = ubo.camera.position; // * vec3(1,1,-1);
vec3 rayD = normalize(vec3((-1.0 + 2.0 * uv) * vec2(ubo.camera.aspectRatio, 1.0), -1.0));
rayD = (ubo.camera.view * vec4( rayD, 0.0 )).xyz;
// Basic color path
uint id = 0;
vec3 finalColor = renderScene(rayO, rayD, id);
// Reflection
if ( REFLECTIONS ) {
float reflectionStrength = REFLECTIONSTRENGTH;
for (int i = 0; i < RAYBOUNCES; i++) {
vec3 reflectionColor = renderScene(rayO, rayD, id);
finalColor = (1.0 - reflectionStrength) * finalColor + reflectionStrength * mix(reflectionColor, finalColor, 1.0 - reflectionStrength);
reflectionStrength *= REFLECTIONFALLOFF;
}
}
imageStore(resultImage, ivec2(gl_GlobalInvocationID.xy), vec4(finalColor, 0.0));
}