// ========================================================================= // ======================== INITIALIZER CONSTANTS ========================== __constant float4 zeroed_float4 = {0.0f, 0.0f, 0.0f, 0.0f}; __constant float3 zeroed_float3 = {0.0f, 0.0f, 0.0f}; __constant float2 zeroed_float2 = {0.0f, 0.0f}; __constant int4 zeroed_int4 = {0, 0, 0, 0}; __constant int3 zeroed_int3 = {0, 0, 0}; __constant int2 zeroed_int2 = {0, 0}; // ========================================================================= // ============================ OCTREE CONSTANTS =========================== // (X, Y, Z) mask for the idx __constant const uchar idx_set_x_mask = 0x1; __constant const uchar idx_set_y_mask = 0x2; __constant const uchar idx_set_z_mask = 0x4; __constant const uchar mask_8[8] = { 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80 }; // Mask for counting the previous valid bits __constant const uchar count_mask_8[8] = { 0x1, 0x3, 0x7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF }; // uint64_t manipulation masks __constant const ulong child_pointer_mask = 0x0000000000007fff; __constant const ulong far_bit_mask = 0x8000; __constant const ulong valid_mask = 0xFF0000; __constant const ulong leaf_mask = 0xFF000000; __constant const ulong contour_pointer_mask = 0xFFFFFF00000000; __constant const ulong contour_mask = 0xFF00000000000000; // ========================================================================= // ========================= RAYCASTER CONSTANTS =========================== constant float4 fog_color = { 0.73f, 0.81f, 0.89f, 0.8f }; constant float4 overshoot_color = { 0.00f, 0.00f, 0.00f, 0.00f }; constant float4 overshoot_color_2 = { 0.00f, 0.00f, 0.00f, 0.00f }; // ========================================================================= // ========================================================================= // ========================================================================= // ========================= HELPER FUNCTIONS ============================== float DistanceBetweenPoints(float3 a, float3 b) { return fast_distance(a, b); } float Distance(float3 a) { return fast_length(a); } // Phong + diffuse lighting function for g // 0 1 2 3 4 5 6 7 8 9 // {r, g, b, i, x, y, z, x', y', z'} float4 view_light(float4 in_color, float3 light, float4 light_color, float3 view, int3 mask) { if (all(light == zeroed_float3)) return zeroed_float4; float d = Distance(light) / 140.0f; d *= d; float diffuse = max(dot(normalize(convert_float3(mask)), normalize(light)), 0.0f); in_color += diffuse * light_color * 0.5f / d; if (dot(light, normalize(convert_float3(mask))) > 0.0f) { // Small dots of light are caused by floating point error // flipping bits on the face mask and screwing up this calculation float3 halfwayVector = normalize(normalize(light) + normalize(view)); float specTmp = max(dot(normalize(convert_float3(mask)), halfwayVector), 0.0f); in_color += pow(specTmp, 8.0f) * light_color * 0.5f / d; } if (in_color.w > 1.0f){ in_color.xyz *= in_color.w; } return in_color; } int rand(int* seed) // 1 <= *seed < m { int const a = 16807; //ie 7**5 int const m = 2147483647; //ie 2**31-1 *seed = ((*seed) * a) % m; return(*seed); } // ========================================================================= // ========================= OCTREE TRAVERSAL ============================== bool get_oct_vox( int3 position, global ulong *octree_descriptor_buffer, global uint *octree_attachment_lookup_buffer, global ulong *octree_attachment_buffer, global ulong *settings_buffer ){ // push the root node to the parent stack ulong current_index = *settings_buffer; ulong head = octree_descriptor_buffer[current_index]; uint parent_stack_position = 0; ulong parent_stack[32]; uchar scale = 0; uchar idx_stack[32]; ulong current_descriptor = 0; bool found = false; parent_stack[parent_stack_position] = head; // Set our initial dimension and the position at the corner of the oct to keep track of our position int dimension = 64; int3 quad_position = zeroed_int3; // While we are not at the required resolution // Traverse down by setting the valid/leaf mask to the subvoxel // Check to see if it is valid // Yes? // Check to see if it is a leaf // No? Break // Yes? Scale down to the next hierarchy, push the parent to the stack // // No? // Break while (dimension > 1) { // So we can be a little bit tricky here and increment our // array index that holds our masks as we build the idx. // Adding 1 for X, 2 for Y, and 4 for Z int mask_index = 0; // Do the logic steps to find which sub oct we step down into if (position.x >= (dimension / 2) + quad_position.x) { // Set our voxel position to the (0,0) of the correct oct quad_position.x += (dimension / 2); // increment the mask index and mentioned above mask_index += 1; // Set the idx to represent the move idx_stack[scale] |= idx_set_x_mask; } if (position.y >= (dimension / 2) + quad_position.y) { quad_position.y |= (dimension / 2); mask_index += 2; idx_stack[scale] |= idx_set_y_mask; } if (position.z >= (dimension / 2) + quad_position.z) { quad_position.z += (dimension / 2); mask_index += 4; idx_stack[scale] |= idx_set_z_mask; } // Check to see if we are on a valid oct if ((head >> 16) & mask_8[mask_index]) { // Check to see if it is a leaf if ((head >> 24) & mask_8[mask_index]) { // If it is, then we cannot traverse further as CP's won't have been generated found = true; return found; } // If all went well and we found a valid non-leaf oct then we will traverse further down the hierarchy scale++; dimension /= 2; // Count the number of valid octs that come before and add it to the index to get the position // Negate it by one as it counts itself int count = popcount((uchar)(head >> 16) & count_mask_8[mask_index]) - 1; // access the element at which head points to and then add the specified number of indices // to get to the correct child descriptor current_index = current_index + (head & child_pointer_mask) + count; head = octree_descriptor_buffer[current_index]; // Increment the parent stack position and put the new oct node as the parent parent_stack_position++; parent_stack[parent_stack_position] = head; } else { // If the oct was not valid, then no CP's exists any further // This implicitly says that if it's non-valid then it must be a leaf!! // It appears that the traversal is now working but I need // to focus on how to now take care of the end condition. // Currently it adds the last parent on the second to lowest // oct CP. Not sure if thats correct found = 0; return found; } } found = 1; return found; } // ========================================================================= // ========================= RAYCASTER ENTRY =============================== __kernel void raycaster( global char* map, constant int3* map_dim, constant int2* resolution, global float3* projection_matrix, global float2* cam_dir, global float3* cam_pos, global float* lights, global int* light_count, __write_only image2d_t image, __read_only image2d_t texture_atlas, constant int2 *atlas_dim, constant int2 *tile_dim, global ulong *octree_descriptor_buffer, global uint *octree_attachment_lookup_buffer, global ulong *octree_attachment_buffer, global ulong *settings_buffer ){ // Get the pixel on the viewport, and find the view matrix ray that matches it int2 pixel = (int2)(get_global_id(0), get_global_id(1)); float3 ray_dir = projection_matrix[pixel.x + (*resolution).x * pixel.y]; // Pitch ray_dir = (float3)( ray_dir.z * sin((*cam_dir).x) + ray_dir.x * cos((*cam_dir).x), ray_dir.y, ray_dir.z * cos((*cam_dir).x) - ray_dir.x * sin((*cam_dir).x) ); // Yaw ray_dir = (float3)( ray_dir.x * cos((*cam_dir).y) - ray_dir.y * sin((*cam_dir).y), ray_dir.x * sin((*cam_dir).y) + ray_dir.y * cos((*cam_dir).y), ray_dir.z ); if (any(ray_dir == zeroed_float3)) return; // Setup the voxel step based on what direction the ray is pointing int3 voxel_step = {1, 1, 1}; voxel_step *= (ray_dir > 0) - (ray_dir < 0); // Setup the voxel coords from the camera origin int3 voxel = convert_int3(*cam_pos); // Delta T is the units a ray must travel along an axis in order to // traverse an integer split float3 delta_t = fabs(1.0f / ray_dir); // Intersection T is the collection of the next intersection points // for all 3 axis XYZ. We take the full positive cardinality when // subtracting the floor, so we must transfer the sign over from // the voxel step float3 intersection_t = delta_t * ((*cam_pos) - ceil(*cam_pos)) * convert_float3(voxel_step); // When we transfer the sign over, we get the correct direction of // the offset, but we merely transposed over the value instead of mirroring // it over the axis like we want. So here, isless returns a boolean if intersection_t // is less than 0 which dictates whether or not we subtract the delta which in effect // mirrors the offset intersection_t -= delta_t * convert_float3(isless(intersection_t, 0)); int distance_traveled = 0; int max_distance = 700; uint bounce_count = 0; int3 face_mask = { 0, 0, 0 }; int voxel_data = 0; float3 face_position = zeroed_float3; float4 voxel_color= zeroed_float4; float2 tile_face_position = zeroed_float2; float3 sign = zeroed_float3; float4 color_accumulator = zeroed_float4; bool shadow_ray = false; // Andrew Woo's raycasting algo while (distance_traveled < max_distance && bounce_count < 4) { // Fancy no branch version of the logic step face_mask = intersection_t.xyz <= min(intersection_t.yzx, intersection_t.zxy); intersection_t += delta_t * fabs(convert_float3(face_mask.xyz)); voxel.xyz += voxel_step.xyz * face_mask.xyz; // Test for out of bounds contions, add fog if (any(voxel >= *map_dim) || any(voxel < 0)){ voxel.xyz -= voxel_step.xyz * face_mask.xyz; color_accumulator = mix(fog_color, voxel_color, 1.0f - max(distance_traveled / 700.0f, 0.0f)); color_accumulator.w *= 4; break; } // If we hit a voxel if (voxel.x < 64 && voxel.y < 64 && voxel.z < 64){ if (get_oct_vox( voxel, octree_descriptor_buffer, octree_attachment_lookup_buffer, octree_attachment_buffer, settings_buffer )){ voxel_data = 5; } else { voxel_data = 0; } } else { voxel_data = map[voxel.x + (*map_dim).x * (voxel.y + (*map_dim).z * (voxel.z))]; } if (voxel_data != 0) { // Determine where on the 2d plane the ray intersected face_position = zeroed_float3; tile_face_position = zeroed_float2; sign = (1.0f, 1.0f, 1.0f); // First determine the percent of the way the ray is towards the next intersection_t // in relation to the xyz position on the plane if (face_mask.x == -1) { sign.x *= -1.0; // the next intersection for this plane - the last intersection of the passed plane / delta of this plane // basically finds how far in on the other 2 axis we are when the ray traversed the plane float z_percent = (intersection_t.z - (intersection_t.x - delta_t.x)) / delta_t.z; float y_percent = (intersection_t.y - (intersection_t.x - delta_t.x)) / delta_t.y; // Since we intersected face x, we know that we are at the face (1.0) // I think the 1.001f rendering bug is the ray thinking it's within the voxel // even though it's sitting on the very edge face_position = (float3)(1.0001f, y_percent, z_percent); tile_face_position = face_position.yz; } else if (face_mask.y == -1) { sign.y *= -1.0; float x_percent = (intersection_t.x - (intersection_t.y - delta_t.y)) / delta_t.x; float z_percent = (intersection_t.z - (intersection_t.y - delta_t.y)) / delta_t.z; face_position = (float3)(x_percent, 1.0001f, z_percent); tile_face_position = face_position.xz; } else if (face_mask.z == -1) { sign.z *= -1.0; float x_percent = (intersection_t.x - (intersection_t.z - delta_t.z)) / delta_t.x; float y_percent = (intersection_t.y - (intersection_t.z - delta_t.z)) / delta_t.y; face_position = (float3)(x_percent, y_percent, 1.0001f); tile_face_position = face_position.xy; } // Because the raycasting process is agnostic to the quadrant // it's working in, we need to transpose the sign over to the face positions. // If we don't it will think that it is always working in the (1, 1, 1) quadrant // and will just "copy" the quadrant. This includes shadows as they use the face_position // in order to cast the intersection ray!! face_position.x = select((face_position.x), (-face_position.x + 1.0f), (int)(ray_dir.x > 0)); tile_face_position.x = select((tile_face_position.x), (-tile_face_position.x + 1.0f), (int)(ray_dir.x < 0)); if (ray_dir.y > 0){ face_position.y = -face_position.y + 1; } else { tile_face_position.x = 1.0 - tile_face_position.x; // We run into the Hairy ball problem, so we need to define // a special case for the zmask if (face_mask.z == -1) { tile_face_position.x = 1.0f - tile_face_position.x; tile_face_position.y = 1.0f - tile_face_position.y; } } face_position.z = select((face_position.z), (-face_position.z + 1.0f), (int)(ray_dir.z > 0)); tile_face_position.y = select((tile_face_position.y), (-tile_face_position.y + 1.0f), (int)(ray_dir.z < 0)); // Now we detect what type of of voxel we intersected and decide whether // to bend the ray, send out a light intersection ray, or add texture color // SHADOWING if (voxel_data == 5 && !shadow_ray){ shadow_ray = true; voxel_color.xyz += (float3)read_imagef( texture_atlas, convert_int2(tile_face_position * convert_float2(*atlas_dim / *tile_dim)) + convert_int2((float2)(3, 0) * convert_float2(*atlas_dim / *tile_dim)) ).xyz/2; color_accumulator = view_light( voxel_color, (convert_float3(voxel) + face_position) - (float3)(lights[4], lights[5], lights[6]), (float4)(lights[0], lights[1], lights[2], lights[3]), (convert_float3(voxel) + face_position) - (*cam_pos), face_mask * voxel_step ); max_distance = DistanceBetweenPoints(convert_float3(voxel), (float3)(lights[4], lights[5], lights[6])); distance_traveled = 0; float3 hit_pos = convert_float3(voxel) + face_position; ray_dir = normalize((float3)(lights[4], lights[5], lights[6]) - hit_pos); if (any(ray_dir == zeroed_float3)) return; voxel -= voxel_step * face_mask; voxel_step = ( 1, 1, 1 ) * ((ray_dir > 0) - (ray_dir < 0)); delta_t = fabs(1.0f / ray_dir); intersection_t = delta_t * ((hit_pos)-floor(hit_pos)) * convert_float3(voxel_step); intersection_t += delta_t * -convert_float3(isless(intersection_t, 0)); // REFLECTION } else if (voxel_data == 6 && !shadow_ray) { voxel_color.xyz += (float3)read_imagef( texture_atlas, convert_int2(tile_face_position * convert_float2(*atlas_dim / *tile_dim)) + convert_int2((float2)(3, 4) * convert_float2(*atlas_dim / *tile_dim)) ).xyz/4; voxel_color.w -= 0.0f; max_distance = 700; distance_traveled = 0; float3 hit_pos = convert_float3(voxel) + face_position; ray_dir *= sign; if (any(ray_dir == zeroed_float3)) return; voxel -= voxel_step * face_mask; voxel_step = ( 1, 1, 1 ); voxel_step *= (ray_dir > 0) - (ray_dir < 0); //voxel = convert_int3(hit_pos); delta_t = fabs(1.0f / ray_dir); intersection_t = delta_t * ((hit_pos)-floor(hit_pos)) * convert_float3(voxel_step); intersection_t += delta_t * -convert_float3(isless(intersection_t, 0)); bounce_count += 1; // SHADOW RAY HIT } else { color_accumulator = 0; break; } } // At the bottom of the while loop, add one to the distance ticker distance_traveled++; } write_imagef( image, pixel, color_accumulator ); return; }