in vec2 TexCoord; out vec4 FragColor; struct GPUNode { vec2 aabb_min; vec2 aabb_max; int left; int right; int line_index; int padding; }; struct GPULine { vec2 pos; vec2 delta; }; layout(std430, binding = 2) buffer LightNodes { GPUNode nodes[]; }; layout(std430, binding = 3) buffer LightLines { GPULine lines[]; }; layout(std430, binding = 4) buffer LightList { vec4 lights[]; }; bool overlapRayAABB(vec2 ray_start2d, vec2 ray_end2d, vec2 aabb_min2d, vec2 aabb_max2d) { // To do: simplify test to use a 2D test vec3 ray_start = vec3(ray_start2d, 0.0); vec3 ray_end = vec3(ray_end2d, 0.0); vec3 aabb_min = vec3(aabb_min2d, -1.0); vec3 aabb_max = vec3(aabb_max2d, 1.0); vec3 c = (ray_start + ray_end) * 0.5f; vec3 w = ray_end - c; vec3 h = (aabb_max - aabb_min) * 0.5f; // aabb.extents(); c -= (aabb_max + aabb_min) * 0.5f; // aabb.center(); vec3 v = abs(w); if (abs(c.x) > v.x + h.x || abs(c.y) > v.y + h.y || abs(c.z) > v.z + h.z) return false; // disjoint; if (abs(c.y * w.z - c.z * w.y) > h.y * v.z + h.z * v.y || abs(c.x * w.z - c.z * w.x) > h.x * v.z + h.z * v.x || abs(c.x * w.y - c.y * w.x) > h.x * v.y + h.y * v.x) return false; // disjoint; return true; // overlap; } float intersectRayLine(vec2 ray_start, vec2 ray_end, int line_index, vec2 raydelta, float rayd, float raydist2) { const float epsilon = 0.0000001; GPULine line = lines[line_index]; vec2 raynormal = vec2(raydelta.y, -raydelta.x); float den = dot(raynormal, line.delta); if (abs(den) > epsilon) { float t_line = (rayd - dot(raynormal, line.pos)) / den; if (t_line >= 0.0 && t_line <= 1.0) { vec2 linehitdelta = line.pos + line.delta * t_line - ray_start; float t = dot(raydelta, linehitdelta) / raydist2; return t > 0.0 ? t : 1.0; } } return 1.0; } bool isLeaf(int node_index) { return nodes[node_index].line_index != -1; } float rayTest(vec2 ray_start, vec2 ray_end) { vec2 raydelta = ray_end - ray_start; float raydist2 = dot(raydelta, raydelta); vec2 raynormal = vec2(raydelta.y, -raydelta.x); float rayd = dot(raynormal, ray_start); if (raydist2 < 1.0) return 1.0; float t = 1.0; int stack[16]; int stack_pos = 1; stack[0] = nodes.length() - 1; while (stack_pos > 0) { int node_index = stack[stack_pos - 1]; if (!overlapRayAABB(ray_start, ray_end, nodes[node_index].aabb_min, nodes[node_index].aabb_max)) { stack_pos--; } else if (isLeaf(node_index)) { t = min(intersectRayLine(ray_start, ray_end, nodes[node_index].line_index, raydelta, rayd, raydist2), t); stack_pos--; } else if (stack_pos == 16) { stack_pos--; // stack overflow } else { stack[stack_pos - 1] = nodes[node_index].left; stack[stack_pos] = nodes[node_index].right; stack_pos++; } } return t; } void main() { int lightIndex = int(gl_FragCoord.y); vec4 light = lights[lightIndex]; float radius = light.w; vec2 lightpos = light.xy; if (radius > 0.0) { vec2 pixelpos; switch (int(gl_FragCoord.x) / 256) { case 0: pixelpos = vec2((gl_FragCoord.x - 128.0) / 128.0, 1.0); break; case 1: pixelpos = vec2(1.0, (gl_FragCoord.x - 384.0) / 128.0); break; case 2: pixelpos = vec2(-(gl_FragCoord.x - 640.0) / 128.0, -1.0); break; case 3: pixelpos = vec2(-1.0, -(gl_FragCoord.x - 896.0) / 128.0); break; } pixelpos = lightpos + pixelpos * radius; float t = rayTest(lightpos, pixelpos); vec2 delta = (pixelpos - lightpos) * t; float dist2 = dot(delta, delta); FragColor = vec4(dist2, 0.0, 0.0, 1.0); } else { FragColor = vec4(1.0, 0.0, 0.0, 1.0); } }