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cuda-based-raytrace
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Started doing basic silhoutte shading + changed background to gray

This commit is contained in:
Martin Opat 2025-01-09 11:43:58 +01:00
parent c5b8b6cff0
commit cc8ef12508
1 changed files with 95 additions and 42 deletions
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137
src/illumination/Raycaster.cu
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@ -23,6 +23,62 @@ __device__ float sampleVolumeNearest(float* volumeData, const int volW, const in
return volumeData[idx]; return volumeData[idx];
} }
// tri-linear interpolation - ready if necessary (but no visible improvement for full volume)
__device__ float sampleVolumeTrilinear(float* volumeData, const int volW, const int volH, const int volD, float fx, float fy, float fz) {
int ix = (int)fx;
int iy = (int)fy;
int iz = (int)fz;
float dx = fx - ix;
float dy = fy - iy;
float dz = fz - iz;
float c00 = sampleVolumeNearest(volumeData, volW, volH, volD, ix, iy, iz) * (1.0f - dx) + sampleVolumeNearest(volumeData, volW, volH, volD, ix + 1, iy, iz) * dx;
float c10 = sampleVolumeNearest(volumeData, volW, volH, volD, ix, iy + 1, iz) * (1.0f - dx) + sampleVolumeNearest(volumeData, volW, volH, volD, ix + 1, iy + 1, iz) * dx;
float c01 = sampleVolumeNearest(volumeData, volW, volH, volD, ix, iy, iz + 1) * (1.0f - dx) + sampleVolumeNearest(volumeData, volW, volH, volD, ix + 1, iy, iz + 1) * dx;
float c11 = sampleVolumeNearest(volumeData, volW, volH, volD, ix, iy + 1, iz + 1) * (1.0f - dx) + sampleVolumeNearest(volumeData, volW, volH, volD, ix + 1, iy + 1, iz + 1) * dx;
float c0 = c00 * (1.0f - dy) + c10 * dy;
float c1 = c01 * (1.0f - dy) + c11 * dy;
return c0 * (1.0f - dz) + c1 * dz;
}
// Transfer function
__device__ float4 transferFunction(float density, Vec3 grad, Point3 pos, Vec3 rayDir) {
float4 result;
// Basic transfer function. TODO: Move to a separate file, and then improve
float alphaSample = density * 0.1f;
// result.w = 1.0f - expf(-density * 0.1f);
Color3 baseColor = Color3::init(density, 0.1f*density, 1.f - density); // TODO: Implement a proper transfer function
Vec3 normal = -grad.normalize();
Vec3 lightDir = (d_lightPos - pos).normalize();
Vec3 viewDir = -rayDir.normalize();
// Apply Phong
Vec3 shadedColor = phongShading(normal, lightDir, viewDir, baseColor);
// Compose
result.x = (1.0f - alphaSample) * shadedColor.x * alphaSample;
result.y = (1.0f - alphaSample) * shadedColor.y * alphaSample;
result.z = (1.0f - alphaSample) * shadedColor.z * alphaSample;
result.w = (1.0f - alphaSample) * alphaSample;
// TODO: Add silhouette - Take gradient of volume dot with view direction (if small then this is a silhouette)
if (grad.dot(viewDir) < epsilon / 100000.0f) {
result.x = 0.0f;
result.y = 0.0f;
result.z = 0.0f;
result.w = 1.0f;
}
return result;
}
// TODO: instead of IMAGEWIDTH and IMAGEHEIGHT this should reflect the windowSize; // TODO: instead of IMAGEWIDTH and IMAGEHEIGHT this should reflect the windowSize;
__global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer) { __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer) {
@ -77,59 +133,56 @@ __global__ void raycastKernel(float* volumeData, FrameBuffer framebuffer) {
intersectAxis(d_cameraPos.y, rayDir.y, 0.0f, (float)VOLUME_HEIGHT); intersectAxis(d_cameraPos.y, rayDir.y, 0.0f, (float)VOLUME_HEIGHT);
intersectAxis(d_cameraPos.z, rayDir.z, 0.0f, (float)VOLUME_DEPTH); intersectAxis(d_cameraPos.z, rayDir.z, 0.0f, (float)VOLUME_DEPTH);
if (tNear > tFar) continue; // No intersectionn if (tNear > tFar){
if (tNear < 0.0f) tNear = 0.0f; // No intersectionn
accumR = 0.9f;
accumG = 0.9f;
accumB = 0.9f;
} else {
if (tNear < 0.0f) tNear = 0.0f;
float colorR = 0.0f, colorG = 0.0f, colorB = 0.0f; float colorR = 0.0f, colorG = 0.0f, colorB = 0.0f;
float alphaAccum = 0.0f; float alphaAccum = 0.0f;
float tCurrent = tNear; float tCurrent = tNear;
while (tCurrent < tFar && alphaAccum < alphaAcumLimit) { while (tCurrent < tFar && alphaAccum < alphaAcumLimit) {
Point3 pos = d_cameraPos + rayDir * tCurrent; Point3 pos = d_cameraPos + rayDir * tCurrent;
// Convert to volume indices // Convert to volume indices
// float fx = pos.x * (VOLUME_WIDTH - 1); // float fx = pos.x * (VOLUME_WIDTH - 1);
// float fy = pos.y * (VOLUME_HEIGHT - 1); // float fy = pos.y * (VOLUME_HEIGHT - 1);
// float fz = pos.z * (VOLUME_DEPTH - 1); // float fz = pos.z * (VOLUME_DEPTH - 1);
int ix = (int)roundf(pos.x); int ix = (int)roundf(pos.x);
int iy = (int)roundf(pos.y); int iy = (int)roundf(pos.y);
int iz = (int)roundf(pos.z); int iz = (int)roundf(pos.z);
// Sample // Sample (pick appropriate method based on volume size)
float density = sampleVolumeNearest(volumeData, VOLUME_WIDTH, VOLUME_HEIGHT, VOLUME_DEPTH, ix, iy, iz); float density = sampleVolumeNearest(volumeData, VOLUME_WIDTH, VOLUME_HEIGHT, VOLUME_DEPTH, ix, iy, iz);
// float density = sampleVolumeTrilinear(volumeData, VOLUME_WIDTH, VOLUME_HEIGHT, VOLUME_DEPTH, pos.x, pos.y, pos.z);
// Basic transfer function. TODO: Move to a separate file, and then improve // If density ~ 0, skip shading
float alphaSample = density * 0.1f; if (density > minAllowedDensity) {
// float alphaSample = 1.0f - expf(-density * 0.1f);
Color3 baseColor = Color3::init(density, 0.1f*density, 1.f - density); // TODO: Implement a proper transfer function
// If density ~ 0, skip shading
if (density > minAllowedDensity) {
Vec3 grad = computeGradient(volumeData, VOLUME_WIDTH, VOLUME_HEIGHT, VOLUME_DEPTH, ix, iy, iz); Vec3 grad = computeGradient(volumeData, VOLUME_WIDTH, VOLUME_HEIGHT, VOLUME_DEPTH, ix, iy, iz);
Vec3 normal = -grad.normalize(); float4 color = transferFunction(density, grad, pos, rayDir);
colorR += color.x;
colorG += color.y;
colorB += color.z;
alphaAccum += color.w;
}
Vec3 lightDir = (d_lightPos - pos).normalize();
Vec3 viewDir = -rayDir.normalize();
// Apply Phong tCurrent += stepSize;
Vec3 shadedColor = phongShading(normal, lightDir, viewDir, baseColor); }
// Compose accumR += colorR;
colorR += (1.0f - alphaAccum) * shadedColor.x * alphaSample; accumG += colorG;
colorG += (1.0f - alphaAccum) * shadedColor.y * alphaSample; accumB += colorB;
colorB += (1.0f - alphaAccum) * shadedColor.z * alphaSample;
alphaAccum += (1.0f - alphaAccum) * alphaSample;
}
// TODO: Add silhouette - Take gradient of volume dot with view direction (if small then this is a silhouette) // float leftover = 1.0f - alphaAccum;
// TODO: Scale volume correctly // accumR = accumR + leftover * 0.9f;
// accumG = accumG + leftover * 0.9f;
tCurrent += stepSize; // accumB = accumB + leftover * 0.9f;
} }
accumR += colorR;
accumG += colorG;
accumB += colorB;
} }
// Average samples // Average samples