super basic path tracing !

This commit is contained in:
ktyl 2021-08-07 17:50:24 +01:00
parent b9616df5b8
commit fe57abce61
4 changed files with 115 additions and 23 deletions

View File

@ -20,6 +20,8 @@ const int SPHERES = 250; // 253 is the maximum?? TODO: use uniform buffer object
layout (location = 12) uniform int _activeSpheres;
layout (location = 13) uniform Sphere _spheres[SPHERES];
uniform float _seed;
layout(local_size_x = 1, local_size_y = 1) in; // size of local work group - 1 pixel
layout(rgba32f, binding = 0) uniform image2D img_output; // rgba32f defines internal format, image2d for random write to output texture
@ -30,7 +32,18 @@ struct Ray
{
vec3 origin;
vec3 direction;
vec3 energy;
};
Ray createRay(vec3 origin, vec3 direction)
{
Ray ray;
ray.origin = origin;
ray.direction = direction;
ray.energy = vec3(1.0,1.0,1.0);
return ray;
}
struct RayHit
{
@ -39,6 +52,17 @@ struct RayHit
vec3 normal;
vec3 albedo;
};
RayHit createRayHit()
{
RayHit hit;
hit.position = vec3(0.0,0.0,0.0);
hit.distance = INF;
hit.normal = vec3(0.0,0.0,0.0);
hit.albedo = vec3(0.0,0.0,0.0);
return hit;
}
void intersectSphere(Ray ray, inout RayHit bestHit, Sphere sphere)
{
@ -75,13 +99,81 @@ Ray createCameraRay(vec2 uv)
dir = _camll + uv.x*_camh + uv.y*_camv;
dir = normalize(dir);
Ray ray;
ray.origin = _cpos;
ray.direction = dir;
Ray ray = createRay(_cpos, dir);
return ray;
};
RayHit trace(Ray ray)
{
RayHit hit = createRayHit();
// TODO: intersect something other than spheres
for (int i = 0; i < _activeSpheres; i++)
{
intersectSphere(ray, hit, _spheres[i]);
}
return hit;
}
float random(vec2 st)
{
return fract(sin(dot(st.xy,vec2(12.9898,78.233)))*43758.5453123);
}
float sdot(vec3 x, vec3 y, float f = 1.0)
{
return clamp(dot(x,y)*f,0.0,1.0);
}
mat3 getTangentSpace(vec3 normal)
{
vec3 helper = abs(normal.x) > 0.99
? vec3(1.0,0.0,0.0)
: vec3(0.0,0.0,1.0);
vec3 tangent = normalize(cross(normal, helper));
vec3 binormal = normalize(cross(normal, tangent));
return mat3(tangent, binormal, normal);
}
vec3 sampleHemisphere(vec3 normal)
{
float cosTheta = random(normal.xy);
float sinTheta = sqrt(max(0.0,1.0-cosTheta*cosTheta));
float phi = 2.0*PI*random(vec2(cosTheta,sinTheta));
vec3 tangentSpaceDir = vec3(cos(phi)*sinTheta, sin(phi)*sinTheta, cosTheta);
// TODO: this lookin sketch af rn
return tangentSpaceDir * getTangentSpace(normal);
}
vec3 scatterLambert(inout Ray ray, RayHit hit)
{
ray.origin = hit.position + hit.normal*0.001;
ray.direction = sampleHemisphere(hit.normal);
ray.energy *= 2.0 * hit.albedo * sdot(hit.normal, ray.direction);
// TODO: ???
return vec3(0.0);
}
vec3 shade(inout Ray ray, RayHit hit)
{
if (hit.distance < INF)
{
return scatterLambert(ray, hit);
}
//ray.energy = vec3(0.0);
// sky color
return vec3(0.68,0.85,0.9);
}
void main()
{
// base pixel colour for the image
@ -89,30 +181,32 @@ void main()
// get index in global work group ie xy position
ivec2 pixel_coords = ivec2(gl_GlobalInvocationID.xy);
// set up ray based on pixel position, project it forward with an orthographic projection
ivec2 dims = imageSize(img_output); // fetch image dimensions
vec2 uv;
uv.x = (float(pixel_coords.x * 2 - dims.x) / dims.x) * dims.x/dims.y; // account for aspect ratio
uv.y = (float(pixel_coords.y * 2 - dims.y) / dims.y);
Ray ray = createCameraRay(uv);
int samples = 2;
int bounces = 2;
RayHit hit;
hit.position = vec3(0.0,0.0,0.0);
hit.distance = INF;
hit.normal = vec3(0.0,0.0,0.0);
hit.albedo = vec3(0.0,0.0,0.0);
for (int i = 0; i < _activeSpheres; i++)
for (int i = 0; i < samples; i++)
{
intersectSphere(ray, hit, _spheres[i]);
// create a ray from the uv
Ray ray = createCameraRay(uv);
// trace the rays path around the scene
for (int j = 0; j < bounces; j++)
{
RayHit hit = trace(ray);
pixel.xyz += ray.energy * shade(ray, hit);
}
}
// TODO: write depth to texture
float depth = hit.distance/INF;
pixel = vec4(hit.albedo,1.0);
pixel *= (1.0-depth);
//float depth = hit.distance/INF;
//pixel = vec4(hit.albedo,1.0);
//pixel *= (1.0-depth);
// output to a specific pixel in the image
imageStore(img_output, pixel_coords, pixel);

View File

@ -1,5 +1,7 @@
#include "cam.h"
const float FOVY = 90.0;
void updateCameraUniforms(GLuint shaderProgram, float aspect)
{
float t = now();
@ -32,9 +34,8 @@ void updateCameraUniforms(GLuint shaderProgram, float aspect)
glUniform3fv(loc, 1, cup);
// camera properties
float fovy = 90.0;
float f = 1.0;
float theta = glm_rad(fovy);
float theta = glm_rad(FOVY);
float h = tan(theta*0.5);
float vph = 2.0*h;
float vpw = aspect*vph;

View File

@ -8,9 +8,7 @@
const int WIDTH = 420;
const int HEIGHT = 420;
// forward declarations
void updateUniforms(GLuint shaderProgram);
//void updateCameraUniforms(GLuint shaderProgram);
int main()
{
@ -59,7 +57,6 @@ int main()
return 0;
}
void updateUniforms(GLuint shaderProgram)
{
float t = now();

View File

@ -5,7 +5,7 @@
* [-] ray tracing time
* [x] perspective
* [x] camera lookat
* [ ] do a bounce
* [x] do a bounce
* [ ] do a 'flect
* [ ] do a 'fract
* [-] depth