💿🐜 Antkeeper source code
https://antkeeper.com
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368 lines
12 KiB
368 lines
12 KiB
/*
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* Copyright (C) 2023 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "render/passes/shadow-map-pass.hpp"
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#include "resources/resource-manager.hpp"
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#include "gl/rasterizer.hpp"
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#include "gl/framebuffer.hpp"
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#include "gl/shader-program.hpp"
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#include "gl/shader-input.hpp"
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#include "gl/drawing-mode.hpp"
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#include "render/context.hpp"
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#include "render/material.hpp"
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#include "scene/camera.hpp"
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#include "scene/collection.hpp"
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#include "scene/light.hpp"
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#include "geom/view-frustum.hpp"
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#include "geom/aabb.hpp"
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#include "config.hpp"
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#include "math/interpolation.hpp"
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#include "math/vector.hpp"
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#include "math/matrix.hpp"
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#include "math/quaternion.hpp"
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#include "math/projection.hpp"
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#include <cmath>
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#include <glad/glad.h>
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namespace render {
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static bool operation_compare(const render::operation& a, const render::operation& b);
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shadow_map_pass::shadow_map_pass(gl::rasterizer* rasterizer, resource_manager* resource_manager):
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pass(rasterizer, nullptr)
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{
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// Load skinned shader program
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unskinned_shader_program = resource_manager->load<gl::shader_program>("depth-unskinned.glsl");
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unskinned_model_view_projection_input = unskinned_shader_program->get_input("model_view_projection");
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// Load unskinned shader program
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skinned_shader_program = resource_manager->load<gl::shader_program>("depth-skinned.glsl");
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skinned_model_view_projection_input = skinned_shader_program->get_input("model_view_projection");
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// Calculate bias-tile matrices
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float4x4 bias_matrix = math::translate(math::matrix4<float>::identity(), float3{0.5f, 0.5f, 0.5f}) * math::scale(math::matrix4<float>::identity(), float3{0.5f, 0.5f, 0.5f});
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float4x4 tile_scale = math::scale(math::matrix4<float>::identity(), float3{0.5f, 0.5f, 1.0f});
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for (int i = 0; i < 4; ++i)
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{
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float x = static_cast<float>(i % 2) * 0.5f;
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float y = static_cast<float>(i / 2) * 0.5f;
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float4x4 tile_matrix = math::translate(math::matrix4<float>::identity(), float3{x, y, 0.0f}) * tile_scale;
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bias_tile_matrices[i] = tile_matrix * bias_matrix;
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}
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}
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shadow_map_pass::~shadow_map_pass()
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{}
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void shadow_map_pass::render(const render::context& ctx, render::queue& queue) const
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{
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// Collect lights
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const std::list<scene::object_base*>* lights = ctx.collection->get_objects(scene::light::object_type_id);
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for (const scene::object_base* object: *lights)
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{
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// Ignore inactive lights
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if (!object->is_active())
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continue;
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// Ignore non-directional lights
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const scene::light* light = static_cast<const scene::light*>(object);
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if (light->get_light_type() != scene::light_type::directional)
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continue;
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// Ignore non-shadow casters
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const scene::directional_light* directional_light = static_cast<const scene::directional_light*>(light);
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if (!directional_light->is_shadow_caster())
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continue;
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// Ignore improperly-configured lights
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if (!directional_light->get_shadow_cascade_count() || !directional_light->get_shadow_framebuffer())
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continue;
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// Render cascaded shadow maps for light
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render_csm(*directional_light, ctx, queue);
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}
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}
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void shadow_map_pass::render_csm(const scene::directional_light& light, const render::context& ctx, render::queue& queue) const
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{
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rasterizer->use_framebuffer(*light.get_shadow_framebuffer());
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// Disable blending
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glDisable(GL_BLEND);
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// Enable depth testing
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glEnable(GL_DEPTH_TEST);
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glDepthFunc(GL_LESS);
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glDepthMask(GL_TRUE);
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// Enable back-face culling
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glEnable(GL_CULL_FACE);
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glCullFace(GL_BACK);
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bool two_sided = false;
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// For half-z buffer
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glDepthRange(-1.0f, 1.0f);
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// Get camera
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const scene::camera& camera = *ctx.camera;
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// Get tweened camera parameters
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const float camera_fov = camera.get_fov_tween().interpolate(ctx.alpha);
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const float camera_aspect_ratio = camera.get_aspect_ratio_tween().interpolate(ctx.alpha);
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const float camera_clip_near = camera.get_clip_near_tween().interpolate(ctx.alpha);
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const float camera_clip_far = camera.get_clip_far_tween().interpolate(ctx.alpha);
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// Calculate distance to shadow cascade depth clipping planes
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const float shadow_clip_far = math::lerp(camera_clip_near, camera_clip_far, light.get_shadow_cascade_coverage());
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const unsigned int cascade_count = light.get_shadow_cascade_count();
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float* cascade_distances = light.get_shadow_cascade_distances();
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float4x4* cascade_matrices = light.get_shadow_cascade_matrices();
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// Calculate cascade far clipping plane distances
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cascade_distances[cascade_count - 1] = shadow_clip_far;
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for (unsigned int i = 0; i < cascade_count - 1; ++i)
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{
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const float weight = static_cast<float>(i + 1) / static_cast<float>(cascade_count);
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// Calculate linear and logarithmic distribution distances
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const float linear_distance = math::lerp(camera_clip_near, shadow_clip_far, weight);
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const float log_distance = math::log_lerp(camera_clip_near, shadow_clip_far, weight);
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// Interpolate between linear and logarithmic distribution distances
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cascade_distances[i] = math::lerp(linear_distance, log_distance, light.get_shadow_cascade_distribution());
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}
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// Calculate viewports for each shadow map
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const int shadow_map_resolution = static_cast<int>(light.get_shadow_framebuffer()->get_depth_attachment()->get_width());
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const int cascade_resolution = shadow_map_resolution / 2;
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int4 shadow_map_viewports[4];
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for (int i = 0; i < 4; ++i)
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{
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int x = i % 2;
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int y = i / 2;
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int4& viewport = shadow_map_viewports[i];
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viewport[0] = x * cascade_resolution;
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viewport[1] = y * cascade_resolution;
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viewport[2] = cascade_resolution;
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viewport[3] = cascade_resolution;
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}
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// Calculate a view-projection matrix from the directional light's transform
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math::transform<float> light_transform = light.get_transform_tween().interpolate(ctx.alpha);
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float3 forward = light_transform.rotation * config::global_forward;
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float3 up = light_transform.rotation * config::global_up;
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float4x4 light_view = math::look_at(light_transform.translation, light_transform.translation + forward, up);
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float4x4 light_projection = math::ortho(-1.0f, 1.0f, -1.0f, 1.0f, -1.0f, 1.0f);
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float4x4 light_view_projection = light_projection * light_view;
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float4x4 cropped_view_projection;
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float4x4 model_view_projection;
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// Sort render queue
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queue.sort(operation_compare);
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gl::shader_program* active_shader_program = nullptr;
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for (unsigned int i = 0; i < cascade_count; ++i)
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{
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// Set viewport for this shadow map
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const int4& viewport = shadow_map_viewports[i];
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rasterizer->set_viewport(viewport[0], viewport[1], viewport[2], viewport[3]);
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// Calculate projection matrix for view camera subfrustum
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const float subfrustum_near = (i) ? cascade_distances[i - 1] : camera_clip_near;
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const float subfrustum_far = cascade_distances[i];
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float4x4 subfrustum_projection = math::perspective_half_z(camera_fov, camera_aspect_ratio, subfrustum_near, subfrustum_far);
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// Calculate view camera subfrustum
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geom::view_frustum<float> subfrustum(subfrustum_projection * ctx.view);
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// Create AABB containing the view camera subfrustum corners
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const std::array<float3, 8>& subfrustum_corners = subfrustum.get_corners();
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geom::aabb<float> subfrustum_aabb = {subfrustum_corners[0], subfrustum_corners[0]};
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for (int j = 1; j < 8; ++j)
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{
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subfrustum_aabb.min_point = math::min(subfrustum_aabb.min_point, subfrustum_corners[j]);
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subfrustum_aabb.max_point = math::max(subfrustum_aabb.max_point, subfrustum_corners[j]);
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}
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// Transform subfrustum AABB into the light clip-space
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geom::aabb<float> cropping_bounds = geom::aabb<float>::transform(subfrustum_aabb, light_view_projection);
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// Quantize clip-space coordinates
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const float texel_scale_x = (cropping_bounds.max_point.x() - cropping_bounds.min_point.x()) / static_cast<float>(cascade_resolution);
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const float texel_scale_y = (cropping_bounds.max_point.y() - cropping_bounds.min_point.y()) / static_cast<float>(cascade_resolution);
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cropping_bounds.min_point.x() = std::floor(cropping_bounds.min_point.x() / texel_scale_x) * texel_scale_x;
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cropping_bounds.max_point.x() = std::floor(cropping_bounds.max_point.x() / texel_scale_x) * texel_scale_x;
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cropping_bounds.min_point.y() = std::floor(cropping_bounds.min_point.y() / texel_scale_y) * texel_scale_y;
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cropping_bounds.max_point.y() = std::floor(cropping_bounds.max_point.y() / texel_scale_y) * texel_scale_y;
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// Recalculate light projection matrix with quantized coordinates
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light_projection = math::ortho_half_z
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(
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cropping_bounds.min_point.x(), cropping_bounds.max_point.x(),
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cropping_bounds.min_point.y(), cropping_bounds.max_point.y(),
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cropping_bounds.min_point.z(), cropping_bounds.max_point.z()
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);
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// Calculate cropped view projection matrix
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cropped_view_projection = light_projection * light_view;
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// Calculate world-space to cascade texture-space transformation matrix
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cascade_matrices[i] = bias_tile_matrices[i] * cropped_view_projection;
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for (const render::operation& operation: queue)
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{
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const render::material* material = operation.material;
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if (material)
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{
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// Skip materials which don't cast shadows
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if (material->get_shadow_mode() == shadow_mode::none)
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continue;
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if (material->is_two_sided() != two_sided)
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{
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if (material->is_two_sided())
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{
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glDisable(GL_CULL_FACE);
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}
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else
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{
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glEnable(GL_CULL_FACE);
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}
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two_sided = material->is_two_sided();
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}
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}
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// Switch shader programs if necessary
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gl::shader_program* shader_program = (operation.bone_count) ? skinned_shader_program : unskinned_shader_program;
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if (active_shader_program != shader_program)
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{
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active_shader_program = shader_program;
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rasterizer->use_program(*active_shader_program);
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}
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// Calculate model-view-projection matrix
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model_view_projection = cropped_view_projection * operation.transform;
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// Upload operation-dependent parameters to shader program
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if (active_shader_program == unskinned_shader_program)
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{
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unskinned_model_view_projection_input->upload(model_view_projection);
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}
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else if (active_shader_program == skinned_shader_program)
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{
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skinned_model_view_projection_input->upload(model_view_projection);
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}
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// Draw geometry
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rasterizer->draw_arrays(*operation.vertex_array, operation.drawing_mode, operation.start_index, operation.index_count);
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}
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}
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}
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bool operation_compare(const render::operation& a, const render::operation& b)
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{
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const bool skinned_a = (a.bone_count);
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const bool skinned_b = (b.bone_count);
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const bool two_sided_a = (a.material) ? a.material->is_two_sided() : false;
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const bool two_sided_b = (b.material) ? b.material->is_two_sided() : false;
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if (skinned_a)
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{
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if (skinned_b)
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{
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// A and B are both skinned, sort by two-sided
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if (two_sided_a)
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{
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if (two_sided_b)
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{
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// A and B are both two-sided, sort by VAO
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return (a.vertex_array < b.vertex_array);
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}
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else
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{
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// A is two-sided, B is one-sided. Render B first
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return false;
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}
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}
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else
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{
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if (two_sided_b)
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{
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// A is one-sided, B is two-sided. Render A first
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return true;
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}
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else
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{
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// A and B are both one-sided, sort by VAO
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return (a.vertex_array < b.vertex_array);
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}
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}
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}
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else
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{
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// A is skinned, B is unskinned. Render B first
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return false;
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}
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}
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else
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{
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if (skinned_b)
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{
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// A is unskinned, B is skinned. Render A first
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return true;
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}
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else
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{
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// A and B are both unskinned, sort by two-sided
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if (two_sided_a)
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{
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if (two_sided_b)
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{
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// A and B are both two-sided, sort by VAO
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return (a.vertex_array < b.vertex_array);
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}
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else
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{
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// A is two-sided, B is one-sided. Render B first
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return false;
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}
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}
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else
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{
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if (two_sided_b)
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{
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// A is one-sided, B is two-sided. Render A first
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return true;
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}
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else
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{
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// A and B are both one-sided, sort by VAO
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return (a.vertex_array < b.vertex_array);
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}
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}
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}
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}
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}
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} // namespace render
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