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500 lines
16 KiB
500 lines
16 KiB
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// =========================================================================
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// ======================== INITIALIZER CONSTANTS ==========================
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__constant float4 zeroed_float4 = {0.0f, 0.0f, 0.0f, 0.0f};
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__constant float3 zeroed_float3 = {0.0f, 0.0f, 0.0f};
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__constant float2 zeroed_float2 = {0.0f, 0.0f};
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__constant int4 zeroed_int4 = {0, 0, 0, 0};
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__constant int3 zeroed_int3 = {0, 0, 0};
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__constant int2 zeroed_int2 = {0, 0};
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// =========================================================================
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// ============================ OCTREE CONSTANTS ===========================
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// (X, Y, Z) mask for the idx
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__constant const uchar idx_set_x_mask = 0x1;
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__constant const uchar idx_set_y_mask = 0x2;
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__constant const uchar idx_set_z_mask = 0x4;
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__constant const uchar mask_8[8] = {
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0x1, 0x2, 0x4, 0x8,
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0x10, 0x20, 0x40, 0x80
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};
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// Mask for counting the previous valid bits
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__constant const uchar count_mask_8[8] = {
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0x1, 0x3, 0x7, 0xF,
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0x1F, 0x3F, 0x7F, 0xFF
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};
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// uint64_t manipulation masks
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__constant const ulong child_pointer_mask = 0x0000000000007fff;
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__constant const ulong far_bit_mask = 0x8000;
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__constant const ulong valid_mask = 0xFF0000;
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__constant const ulong leaf_mask = 0xFF000000;
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__constant const ulong contour_pointer_mask = 0xFFFFFF00000000;
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__constant const ulong contour_mask = 0xFF00000000000000;
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// =========================================================================
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// ========================= RAYCASTER CONSTANTS ===========================
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constant float4 fog_color = { 0.73f, 0.81f, 0.89f, 0.8f };
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constant float4 overshoot_color = { 0.00f, 0.00f, 0.00f, 0.00f };
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constant float4 overshoot_color_2 = { 0.00f, 0.00f, 0.00f, 0.00f };
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// =========================================================================
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// =========================================================================
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// =========================================================================
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// ========================= HELPER FUNCTIONS ==============================
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float DistanceBetweenPoints(float3 a, float3 b) {
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return fast_distance(a, b);
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}
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float Distance(float3 a) {
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return fast_length(a);
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}
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// Phong + diffuse lighting function for g
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// 0 1 2 3 4 5 6 7 8 9
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// {r, g, b, i, x, y, z, x', y', z'}
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float4 view_light(float4 in_color, float3 light, float4 light_color, float3 view, int3 mask) {
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if (all(light == zeroed_float3))
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return zeroed_float4;
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float d = Distance(light) / 100.0f;
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d *= d;
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float diffuse = max(dot(normalize(convert_float3(mask)), normalize(light)), 0.0f);
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in_color += diffuse * light_color * 0.5f / d;
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if (dot(light, normalize(convert_float3(mask))) > 0.0f)
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{
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// Small dots of light are caused by floating point error
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// flipping bits on the face mask and screwing up this calculation
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float3 halfwayVector = normalize(normalize(light) + normalize(view));
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float specTmp = max(dot(normalize(convert_float3(mask)), halfwayVector), 0.0f);
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in_color += pow(specTmp, 8.0f) * light_color * 0.5f / d;
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}
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if (in_color.w > 1.0f){
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in_color.xyz *= in_color.w;
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}
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return in_color;
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}
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int rand(int* seed) // 1 <= *seed < m
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{
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int const a = 16807; //ie 7**5
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int const m = 2147483647; //ie 2**31-1
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*seed = ((*seed) * a) % m;
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return(*seed);
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}
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// =========================================================================
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// ========================= OCTREE TRAVERSAL ==============================
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bool get_oct_vox(
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int3 position,
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global ulong *octree_descriptor_buffer,
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global uint *octree_attachment_lookup_buffer,
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global ulong *octree_attachment_buffer,
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global ulong *settings_buffer
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){
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// push the root node to the parent stack
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ulong current_index = *settings_buffer;
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ulong head = octree_descriptor_buffer[current_index];
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uint parent_stack_position = 0;
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ulong parent_stack[32];
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uchar scale = 0;
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uchar idx_stack[32];
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ulong current_descriptor = 0;
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bool found = false;
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parent_stack[parent_stack_position] = head;
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// Set our initial dimension and the position at the corner of the oct to keep track of our position
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int dimension = 64;
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int3 quad_position = zeroed_int3;
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// While we are not at the required resolution
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// Traverse down by setting the valid/leaf mask to the subvoxel
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// Check to see if it is valid
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// Yes?
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// Check to see if it is a leaf
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// No? Break
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// Yes? Scale down to the next hierarchy, push the parent to the stack
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//
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// No?
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// Break
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while (dimension > 1) {
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// So we can be a little bit tricky here and increment our
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// array index that holds our masks as we build the idx.
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// Adding 1 for X, 2 for Y, and 4 for Z
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int mask_index = 0;
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// Do the logic steps to find which sub oct we step down into
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if (position.x >= (dimension / 2) + quad_position.x) {
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// Set our voxel position to the (0,0) of the correct oct
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quad_position.x += (dimension / 2);
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// increment the mask index and mentioned above
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mask_index += 1;
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// Set the idx to represent the move
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idx_stack[scale] |= idx_set_x_mask;
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}
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if (position.y >= (dimension / 2) + quad_position.y) {
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quad_position.y |= (dimension / 2);
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mask_index += 2;
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// TODO What is up with the binary operator on this one?
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// Alright, I switched it over and seems not to have done anything?
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// idx_stack[scale] ^= idx_set_y_mask;
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idx_stack[scale] |= idx_set_y_mask;
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}
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if (position.z >= (dimension / 2) + quad_position.z) {
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quad_position.z += (dimension / 2);
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mask_index += 4;
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idx_stack[scale] |= idx_set_z_mask;
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}
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// Check to see if we are on a valid oct
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if ((head >> 16) & mask_8[mask_index]) {
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// Check to see if it is a leaf
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if ((head >> 24) & mask_8[mask_index]) {
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// If it is, then we cannot traverse further as CP's won't have been generated
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found = true;
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return found;
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}
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// If all went well and we found a valid non-leaf oct then we will traverse further down the hierarchy
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scale++;
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dimension /= 2;
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// Count the number of valid octs that come before and add it to the index to get the position
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// Negate it by one as it counts itself
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int count = popcount((uchar)(head >> 16) & count_mask_8[mask_index]) - 1;
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// access the element at which head points to and then add the specified number of indices
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// to get to the correct child descriptor
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current_index = current_index + (head & child_pointer_mask) + count;
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head = octree_descriptor_buffer[current_index];
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// Increment the parent stack position and put the new oct node as the parent
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parent_stack_position++;
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parent_stack[parent_stack_position] = head;
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}
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else {
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// If the oct was not valid, then no CP's exists any further
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// This implicitly says that if it's non-valid then it must be a leaf!!
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// It appears that the traversal is now working but I need
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// to focus on how to now take care of the end condition.
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// Currently it adds the last parent on the second to lowest
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// oct CP. Not sure if thats correct
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found = 0;
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return found;
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}
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}
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found = 1;
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return found;
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}
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// =========================================================================
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// ========================= RAYCASTER ENTRY ===============================
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__kernel void raycaster(
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global char* map,
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constant int3* map_dim,
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constant int2* resolution,
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global float3* projection_matrix,
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global float2* cam_dir,
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global float3* cam_pos,
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global float* lights,
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global int* light_count,
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__write_only image2d_t image,
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__read_only image2d_t texture_atlas,
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constant int2 *atlas_dim,
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constant int2 *tile_dim,
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global ulong *octree_descriptor_buffer,
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global uint *octree_attachment_lookup_buffer,
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global ulong *octree_attachment_buffer,
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global ulong *settings_buffer
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){
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// Get the pixel on the viewport, and find the view matrix ray that matches it
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int2 pixel = (int2)(get_global_id(0), get_global_id(1));
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float3 ray_dir = projection_matrix[pixel.x + (*resolution).x * pixel.y];
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// Pitch
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ray_dir = (float3)(
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ray_dir.z * sin((*cam_dir).x) + ray_dir.x * cos((*cam_dir).x),
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ray_dir.y,
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ray_dir.z * cos((*cam_dir).x) - ray_dir.x * sin((*cam_dir).x)
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);
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// Yaw
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ray_dir = (float3)(
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ray_dir.x * cos((*cam_dir).y) - ray_dir.y * sin((*cam_dir).y),
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ray_dir.x * sin((*cam_dir).y) + ray_dir.y * cos((*cam_dir).y),
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ray_dir.z
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);
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if (any(ray_dir == zeroed_float3))
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return;
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// Setup the voxel step based on what direction the ray is pointing
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int3 voxel_step = {1, 1, 1};
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voxel_step *= (ray_dir > 0) - (ray_dir < 0);
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// Setup the voxel coords from the camera origin
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int3 voxel = convert_int3(*cam_pos);
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// Delta T is the units a ray must travel along an axis in order to
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// traverse an integer split
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float3 delta_t = fabs(1.0f / ray_dir);
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// Intersection T is the collection of the next intersection points
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// for all 3 axis XYZ. We take the full positive cardinality when
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// subtracting the floor, so we must transfer the sign over from
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// the voxel step
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float3 intersection_t = delta_t * ((*cam_pos) - ceil(*cam_pos)) * convert_float3(voxel_step);
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// When we transfer the sign over, we get the correct direction of
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// the offset, but we merely transposed over the value instead of mirroring
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// it over the axis like we want. So here, isless returns a boolean if intersection_t
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// is less than 0 which dictates whether or not we subtract the delta which in effect
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// mirrors the offset
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intersection_t -= delta_t * convert_float3(isless(intersection_t, 0));
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int distance_traveled = 0;
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int max_distance = 700;
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uint bounce_count = 0;
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int3 face_mask = { 0, 0, 0 };
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int voxel_data = 0;
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float3 face_position = zeroed_float3;
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float4 voxel_color= zeroed_float4;
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float2 tile_face_position = zeroed_float2;
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float3 sign = zeroed_float3;
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float4 color_accumulator = zeroed_float4;
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bool shadow_ray = false;
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// Andrew Woo's raycasting algo
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while (distance_traveled < max_distance && bounce_count < 4) {
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// Fancy no branch version of the logic step
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face_mask = intersection_t.xyz <= min(intersection_t.yzx, intersection_t.zxy);
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intersection_t += delta_t * fabs(convert_float3(face_mask.xyz));
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voxel.xyz += voxel_step.xyz * face_mask.xyz;
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// Test for out of bounds contions, add fog
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if (any(voxel >= *map_dim) || any(voxel < 0)){
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voxel.xyz -= voxel_step.xyz * face_mask.xyz;
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color_accumulator = mix(fog_color, voxel_color, 1.0f - max(distance_traveled / 700.0f, 0.0f));
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break;
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}
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// If we hit a voxel
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if (voxel.x < 64 && voxel.y < 64 && voxel.z < 64){
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if (get_oct_vox(
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voxel,
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octree_descriptor_buffer,
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octree_attachment_lookup_buffer,
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octree_attachment_buffer,
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settings_buffer
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)){
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voxel_data = 5;
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} else {
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voxel_data = 0;
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}
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} else {
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voxel_data = map[voxel.x + (*map_dim).x * (voxel.y + (*map_dim).z * (voxel.z))];
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}
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if (voxel_data != 0) {
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// Determine where on the 2d plane the ray intersected
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face_position = zeroed_float3;
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tile_face_position = zeroed_float2;
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sign = (1.0f, 1.0f, 1.0f);
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// First determine the percent of the way the ray is towards the next intersection_t
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// in relation to the xyz position on the plane
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if (face_mask.x == -1) {
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sign.x *= -1.0;
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// the next intersection for this plane - the last intersection of the passed plane / delta of this plane
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// basically finds how far in on the other 2 axis we are when the ray traversed the plane
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float z_percent = (intersection_t.z - (intersection_t.x - delta_t.x)) / delta_t.z;
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float y_percent = (intersection_t.y - (intersection_t.x - delta_t.x)) / delta_t.y;
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// Since we intersected face x, we know that we are at the face (1.0)
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// I think the 1.001f rendering bug is the ray thinking it's within the voxel
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// even though it's sitting on the very edge
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face_position = (float3)(1.0001f, y_percent, z_percent);
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tile_face_position = face_position.yz;
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}
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else if (face_mask.y == -1) {
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sign.y *= -1.0;
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float x_percent = (intersection_t.x - (intersection_t.y - delta_t.y)) / delta_t.x;
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float z_percent = (intersection_t.z - (intersection_t.y - delta_t.y)) / delta_t.z;
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face_position = (float3)(x_percent, 1.0001f, z_percent);
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tile_face_position = face_position.xz;
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}
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else if (face_mask.z == -1) {
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sign.z *= -1.0;
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float x_percent = (intersection_t.x - (intersection_t.z - delta_t.z)) / delta_t.x;
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float y_percent = (intersection_t.y - (intersection_t.z - delta_t.z)) / delta_t.y;
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face_position = (float3)(x_percent, y_percent, 1.0001f);
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tile_face_position = face_position.xy;
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}
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// Because the raycasting process is agnostic to the quadrant
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// it's working in, we need to transpose the sign over to the face positions.
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// If we don't it will think that it is always working in the (1, 1, 1) quadrant
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// and will just "copy" the quadrant. This includes shadows as they use the face_position
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// in order to cast the intersection ray!!
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face_position.x = select((face_position.x), (-face_position.x + 1.0f), (int)(ray_dir.x > 0));
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tile_face_position.x = select((tile_face_position.x), (-tile_face_position.x + 1.0f), (int)(ray_dir.x < 0));
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if (ray_dir.y > 0){
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face_position.y = -face_position.y + 1;
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} else {
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tile_face_position.x = 1.0 - tile_face_position.x;
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// We run into the Hairy ball problem, so we need to define
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// a special case for the zmask
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if (face_mask.z == -1) {
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tile_face_position.x = 1.0f - tile_face_position.x;
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tile_face_position.y = 1.0f - tile_face_position.y;
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}
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}
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face_position.z = select((face_position.z), (-face_position.z + 1.0f), (int)(ray_dir.z > 0));
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tile_face_position.y = select((tile_face_position.y), (-tile_face_position.y + 1.0f), (int)(ray_dir.z < 0));
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// Now we detect what type of of voxel we intersected and decide whether
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// to bend the ray, send out a light intersection ray, or add texture color
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// SHADOWING
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if (voxel_data == 5 && !shadow_ray){
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shadow_ray = true;
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voxel_color.xyz += (float3)read_imagef(
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texture_atlas,
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convert_int2(tile_face_position * convert_float2(*atlas_dim / *tile_dim)) +
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convert_int2((float2)(3, 0) * convert_float2(*atlas_dim / *tile_dim))
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).xyz/2;
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color_accumulator = view_light(
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voxel_color,
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(convert_float3(voxel) + face_position) - (float3)(lights[4], lights[5], lights[6]),
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(float4)(lights[0], lights[1], lights[2], lights[3]),
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(convert_float3(voxel) + face_position) - (*cam_pos),
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face_mask * voxel_step
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);
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max_distance = DistanceBetweenPoints(convert_float3(voxel), (float3)(lights[4], lights[5], lights[6]));
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distance_traveled = 0;
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float3 hit_pos = convert_float3(voxel) + face_position;
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ray_dir = normalize((float3)(lights[4], lights[5], lights[6]) - hit_pos);
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if (any(ray_dir == zeroed_float3))
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return;
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voxel -= voxel_step * face_mask;
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voxel_step = ( 1, 1, 1 );
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voxel_step *= (ray_dir > 0) - (ray_dir < 0);
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//voxel = convert_int3(hit_pos);
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delta_t = fabs(1.0f / ray_dir);
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intersection_t = delta_t * ((hit_pos)-floor(hit_pos)) * convert_float3(voxel_step);
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intersection_t += delta_t * -convert_float3(isless(intersection_t, 0));
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// REFLECTION
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} else if (voxel_data == 6 && !shadow_ray) {
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voxel_color.xyz += (float3)read_imagef(
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texture_atlas,
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convert_int2(tile_face_position * convert_float2(*atlas_dim / *tile_dim)) +
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convert_int2((float2)(3, 4) * convert_float2(*atlas_dim / *tile_dim))
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).xyz/2;
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voxel_color.w -= 0.3f;
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max_distance = 700;
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distance_traveled = 0;
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float3 hit_pos = convert_float3(voxel) + face_position;
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ray_dir *= sign;
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if (any(ray_dir == zeroed_float3))
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return;
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voxel -= voxel_step * face_mask;
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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 /= 5;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// At the bottom of the while loop, add one to the distance ticker
|
|
distance_traveled++;
|
|
}
|
|
write_imagef(
|
|
image,
|
|
pixel,
|
|
color_accumulator
|
|
);
|
|
|
|
return;
|
|
}
|