COSC-3P93-Project/Step 3/resources/opencl/sphereray.cl

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Common Lisp
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2022-12-10 14:25:09 -05:00
// these values get dynamically defined by the preprocessor
#define maxTriangleCount 336
#define objectCount 6
#define imageWidth 800
#define imageHeight 600
#define imageOrigin (float4)(0,0,0,0)
#define horizontalAxis (float4)(0,0,0,0)
#define verticalAxis (float4)(0,0,0,0)
#define cameraPosition (float4)(0,0,0,0)
#define MAX_DEPTH 500
#define MAX_PER_PIXEL 500
#define PI 3.1415926535897
struct Ray {
// the starting point for our ray
float4 start;
// and the direction it is currently traveling
float4 direction;
float4 inverseDirection;
};
struct HitData {
// the hit point on the object
float4 hitPoint;
// the normal of that hit point
float4 normal;
// the length of the vector from its origin in its direction.
float length;
// Texture UV Coords.
float u, v;
};
struct ScatterResults {
// returns true to recast the ray with the provided ray
bool scattered;
// the new ray to be cast if scattered
struct Ray newRay;
// the color of the material
float4 attenuationColor;
};
float4 along(struct Ray ray, float length) {
return ray.start + length * ray.direction;
}
float lengthSquared(float4 vec){
return vec.x * vec.x + vec.y * vec.y + vec.z * vec.z + vec.w * vec.w;
}
float magnitude(float4 vec){
return sqrt(lengthSquared(vec));
}
// // // reads one unsigned long of data from the objects buffer.
float4 getVector(__global unsigned char* buffer, unsigned long* currentByte){
float4 val = *((global float4*)(buffer));
*currentByte += sizeof(float4);
return val;
}
struct Ray projectRay(float x, float y){
float transformedX = (x / (imageWidth - 1));
float transformedY = (y / (imageHeight - 1));
struct Ray ray;
ray.start = cameraPosition;
ray.direction = imageOrigin + transformedX * horizontalAxis + transformedY * verticalAxis - cameraPosition;
ray.inverseDirection = 1.0f / ray.direction;
return ray;
}
bool checkIfHit(struct HitData* data, struct Ray ray, float4 position, float radius, float min, float max){
float radiusSquared = radius * radius;
float4 rayWRTSphere = ray.start - position;
// now determine the discriminant for the quadratic formula for the function of line sphere intercept
float a = lengthSquared(ray.direction);
float b = dot(rayWRTSphere, ray.direction);
float c = lengthSquared(rayWRTSphere) - radiusSquared;
// > 0: the hit has two roots, meaning we hit both sides of the sphere
// = 0: the ray has one root, we hit the edge of the sphere
// < 0: ray isn't inside the sphere.
float discriminant = b * b - (a * c);
// < 0: ray isn't inside the sphere. Don't need to bother calculating the roots.
if (discriminant < 0) {
return false;
}
// now we have to find the root which exists inside our range [min,max]
float root = (-b - sqrt(discriminant)) / a;
// if the first root isn't in our range
if (root < min || root > max) {
// check the second root
root = (-b + sqrt(discriminant)) / a;
if (root < min || root > max) {
// if the second isn't in the range then we also must return false.
return false;
}
}
// the hit point is where the ray is when extended to the root
float4 RayAtRoot = along(ray,root);
// The normal of a sphere is just the point of the hit minus the center position
float4 normal = (RayAtRoot - position) / radius;
// calculate the uv coords and normalize to [0, 1]
float u = (atan2(-normal.z, normal.x) + PI) / (2 * PI);
float v = acos(normal.y) / PI;
// have to invert the v since we have to invert the v again later due to triangles
data->hitPoint = RayAtRoot;
data->normal = normal;
data->length = root;
data->u = u;
data->v = 1.0 - v;
return true;
}
__kernel void raycast(__write_only image2d_t outputImage, __global unsigned char* objects, __global unsigned char* randoms) {
unsigned long currentByte = 0;
int x = get_global_id(0);
int y = get_global_id(1);
float4 color = (float4)(0.0);
struct HitData hitData1;
if (checkIfHit(&hitData1, projectRay(x, y), (float4)(0.0f, -10, 0.0f, 0.0f), 10, 0, 1000)){
color = (float4)(hitData1.normal.x, hitData1.normal.y, hitData1.normal.z, 1.0f);
}
struct HitData hitData2;
if (checkIfHit(&hitData2, projectRay(x, y), (float4)(0.0f, 0, 0.0f, 0.0f), 1, 0, 1000)){
color = (float4)(0.0f, 1.0f, 0.0f, 1.0f);
}
write_imagef(outputImage, (int2)(x, y), (float4)(sqrt(color.x), sqrt(color.y), sqrt(color.z), 1.0f));
}