/* * Copyright (C) 2023 Christopher J. Howard * * This file is part of Antkeeper source code. * * Antkeeper source code is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * Antkeeper source code is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Antkeeper source code. If not, see . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include namespace render { static bool operation_compare(const render::operation* a, const render::operation* b); shadow_map_pass::shadow_map_pass(gl::rasterizer* rasterizer, resource_manager* resource_manager): pass(rasterizer, nullptr) { std::unordered_map definitions; definitions["VERTEX_POSITION"] = std::to_string(vertex_attribute::position); definitions["VERTEX_UV"] = std::to_string(vertex_attribute::uv); definitions["VERTEX_NORMAL"] = std::to_string(vertex_attribute::normal); definitions["VERTEX_TANGENT"] = std::to_string(vertex_attribute::tangent); definitions["VERTEX_COLOR"] = std::to_string(vertex_attribute::color); definitions["VERTEX_BONE_INDEX"] = std::to_string(vertex_attribute::bone_index); definitions["VERTEX_BONE_WEIGHT"] = std::to_string(vertex_attribute::bone_weight); definitions["VERTEX_BONE_WEIGHT"] = std::to_string(vertex_attribute::bone_weight); definitions["MAX_BONE_COUNT"] = std::to_string(64); // Load unskinned shader template auto unskinned_shader_template = resource_manager->load("depth-unskinned.glsl"); // Build unskinned shader program unskinned_shader_program = unskinned_shader_template->build(definitions); if (!unskinned_shader_program->linked()) { debug::log::error("Failed to build unskinned shadow map shader program: {}", unskinned_shader_program->info()); debug::log::warning("{}", unskinned_shader_template->configure(gl::shader_stage::vertex)); } unskinned_model_view_projection_var = unskinned_shader_program->variable("model_view_projection"); // Load skinned shader template auto skinned_shader_template = resource_manager->load("depth-skinned.glsl"); // Build skinned shader program skinned_shader_program = skinned_shader_template->build(definitions); if (!skinned_shader_program->linked()) { debug::log::error("Failed to build skinned shadow map shader program: {}", skinned_shader_program->info()); debug::log::warning("{}", skinned_shader_template->configure(gl::shader_stage::vertex)); } skinned_model_view_projection_var = skinned_shader_program->variable("model_view_projection"); skinned_matrix_palette_var = skinned_shader_program->variable("matrix_palette"); } void shadow_map_pass::render(render::context& ctx) { // For each light const auto& lights = ctx.collection->get_objects(scene::light::object_type_id); for (scene::object_base* object: lights) { // Ignore non-directional lights auto& light = static_cast(*object); if (light.get_light_type() != scene::light_type::directional) { continue; } // Ignore non-shadow casters auto& directional_light = static_cast(light); if (!directional_light.is_shadow_caster()) { continue; } // Ignore improperly-configured lights if (!directional_light.get_shadow_framebuffer() || !directional_light.get_shadow_cascade_count()) { continue; } // Render cascaded shadow maps render_csm(directional_light, ctx); } } void shadow_map_pass::render_csm(scene::directional_light& light, render::context& ctx) { // Get light layer mask const auto light_layer_mask = light.get_layer_mask(); if (!light_layer_mask & ctx.camera->get_layer_mask()) { return; } rasterizer->use_framebuffer(*light.get_shadow_framebuffer()); // Disable blending glDisable(GL_BLEND); // Enable depth testing glEnable(GL_DEPTH_TEST); glDepthFunc(GL_GREATER); glDepthMask(GL_TRUE); // Enable back-face culling glEnable(GL_CULL_FACE); glCullFace(GL_BACK); bool two_sided = false; // For half-z buffer glDepthRange(-1.0f, 1.0f); // Get camera const scene::camera& camera = *ctx.camera; // Calculate distance to shadow cascade depth clipping planes const float shadow_clip_far = math::lerp(camera.get_clip_near(), camera.get_clip_far(), light.get_shadow_cascade_coverage()); // Get light shadow cascade distances and matrices const auto cascade_count = light.get_shadow_cascade_count(); const auto cascade_distances = light.get_shadow_cascade_distances(); const auto cascade_matrices = light.get_shadow_cascade_matrices(); // Calculate cascade far clipping plane distances cascade_distances[cascade_count - 1] = shadow_clip_far; for (unsigned int i = 0; i < cascade_count - 1; ++i) { const float weight = static_cast(i + 1) / static_cast(cascade_count); // Calculate linear and logarithmic distribution distances const float linear_distance = math::lerp(camera.get_clip_near(), shadow_clip_far, weight); const float log_distance = math::log_lerp(camera.get_clip_near(), shadow_clip_far, weight); // Interpolate between linear and logarithmic distribution distances cascade_distances[i] = math::lerp(linear_distance, log_distance, light.get_shadow_cascade_distribution()); } // Calculate viewports for each shadow map const int shadow_map_resolution = static_cast(light.get_shadow_framebuffer()->get_depth_attachment()->get_width()); const int cascade_resolution = shadow_map_resolution >> 1; math::ivec4 shadow_map_viewports[4]; for (int i = 0; i < 4; ++i) { int x = i % 2; int y = i / 2; math::ivec4& viewport = shadow_map_viewports[i]; viewport[0] = x * cascade_resolution; viewport[1] = y * cascade_resolution; viewport[2] = cascade_resolution; viewport[3] = cascade_resolution; } // Sort render operations std::sort(std::execution::par_unseq, ctx.operations.begin(), ctx.operations.end(), operation_compare); gl::shader_program* active_shader_program = nullptr; // Precalculate frustum minimal bounding sphere terms const auto k = std::sqrt(1.0f + camera.get_aspect_ratio() * camera.get_aspect_ratio()) * std::tan(camera.get_vertical_fov() * 0.5f); const auto k2 = k * k; const auto k4 = k2 * k2; for (unsigned int i = 0; i < cascade_count; ++i) { // Set viewport for this shadow map const math::ivec4& viewport = shadow_map_viewports[i]; rasterizer->set_viewport(viewport[0], viewport[1], viewport[2], viewport[3]); // Find minimal bounding sphere of subfrustum in view-space // @see https://lxjk.github.io/2017/04/15/Calculate-Minimal-Bounding-Sphere-of-Frustum.html geom::sphere subfrustum_bounds; { // Get subfrustum near and far distances const auto n = (i) ? cascade_distances[i - 1] : camera.get_clip_near(); const auto f = cascade_distances[i]; if (k2 >= (f - n) / (f + n)) { subfrustum_bounds.center = {0, 0, -f}; subfrustum_bounds.radius = f * k; } else { subfrustum_bounds.center = {0, 0, -0.5f * (f + n) * (1.0f + k2)}; subfrustum_bounds.radius = 0.5f * std::sqrt((k4 + 2.0f * k2 + 1.0f) * (f * f + n * n) + 2.0f * f * (k4 - 1.0f) * n); } } // Transform subfrustum bounds into world-space subfrustum_bounds.center = camera.get_translation() + camera.get_rotation() * subfrustum_bounds.center; // Discretize view-space subfrustum bounds const auto texel_scale = static_cast(cascade_resolution) / (subfrustum_bounds.radius * 2.0f); subfrustum_bounds.center = math::conjugate(light.get_rotation()) * subfrustum_bounds.center; subfrustum_bounds.center = math::floor(subfrustum_bounds.center * texel_scale) / texel_scale; subfrustum_bounds.center = light.get_rotation() * subfrustum_bounds.center; // Construct light view matrix const auto light_view = math::look_at(subfrustum_bounds.center, subfrustum_bounds.center + light.get_direction(), light.get_rotation() * math::fvec3{0, 1, 0}); // Construct light projection matrix (reversed half-z) const auto light_projection = math::ortho_half_z ( -subfrustum_bounds.radius, subfrustum_bounds.radius, -subfrustum_bounds.radius, subfrustum_bounds.radius, subfrustum_bounds.radius, -subfrustum_bounds.radius ); // Construct light view-projection matrix const auto light_view_projection = light_projection * light_view; // Update world-space to cascade texture-space transformation matrix cascade_matrices[i] = light.get_shadow_bias_scale_matrices()[i] * light_view_projection; for (const render::operation* operation: ctx.operations) { // Skip operations which don't share any layers with the shadow-casting light if (!(operation->layer_mask & light_layer_mask)) { continue; } const render::material* material = operation->material.get(); if (material) { // Skip materials which don't cast shadows if (material->get_shadow_mode() == material_shadow_mode::none) { continue; } if (material->is_two_sided() != two_sided) { if (material->is_two_sided()) { glDisable(GL_CULL_FACE); } else { glEnable(GL_CULL_FACE); } two_sided = material->is_two_sided(); } } // Switch shader programs if necessary gl::shader_program* shader_program = (operation->matrix_palette.empty()) ? unskinned_shader_program.get() : skinned_shader_program.get(); if (active_shader_program != shader_program) { active_shader_program = shader_program; rasterizer->use_program(*active_shader_program); } // Calculate model-view-projection matrix math::fmat4 model_view_projection = light_view_projection * operation->transform; // Upload operation-dependent parameters to shader program if (active_shader_program == unskinned_shader_program.get()) { unskinned_model_view_projection_var->update(model_view_projection); } else if (active_shader_program == skinned_shader_program.get()) { skinned_model_view_projection_var->update(model_view_projection); skinned_matrix_palette_var->update(operation->matrix_palette); } // Draw geometry rasterizer->draw_arrays(*operation->vertex_array, operation->drawing_mode, operation->start_index, operation->index_count); } } } bool operation_compare(const render::operation* a, const render::operation* b) { const bool skinned_a = !a->matrix_palette.empty(); const bool skinned_b = !b->matrix_palette.empty(); const bool two_sided_a = (a->material) ? a->material->is_two_sided() : false; const bool two_sided_b = (b->material) ? b->material->is_two_sided() : false; if (skinned_a) { if (skinned_b) { // A and B are both skinned, sort by two-sided if (two_sided_a) { if (two_sided_b) { // A and B are both two-sided, sort by VAO return (a->vertex_array < b->vertex_array); } else { // A is two-sided, B is one-sided. Render B first return false; } } else { if (two_sided_b) { // A is one-sided, B is two-sided. Render A first return true; } else { // A and B are both one-sided, sort by VAO return (a->vertex_array < b->vertex_array); } } } else { // A is skinned, B is unskinned. Render B first return false; } } else { if (skinned_b) { // A is unskinned, B is skinned. Render A first return true; } else { // A and B are both unskinned, sort by two-sided if (two_sided_a) { if (two_sided_b) { // A and B are both two-sided, sort by VAO return (a->vertex_array < b->vertex_array); } else { // A is two-sided, B is one-sided. Render B first return false; } } else { if (two_sided_b) { // A is one-sided, B is two-sided. Render A first return true; } else { // A and B are both one-sided, sort by VAO return (a->vertex_array < b->vertex_array); } } } } } } // namespace render