Function GetShadowableTris

Source/Main/engine.cpp:3791–3891

};

void GetShadowableTris(SceneGraph* scenegraph) {
    // For each cascade size
    // Divide scene into tiles
    // Draw tiles using shader that renders the triangle and object id to a texture
    // Read the texture and add triangle/object pair to a set
    // Create model for each tile

    Graphics* graphics = Graphics::Instance();
    Camera* camera = ActiveCameras::Get();

    vec3 light_dir = scenegraph->primary_light.pos;
    vec3 basis[3];
    basis[2] = light_dir;
    basis[0] = normalize(cross(vec3(0, 1, 0), basis[2]));
    basis[1] = normalize(cross(basis[0], basis[2]));

    vec3 camera_pos;

    ShadowCascadeParams shadow_params;
    for (int i = 0; i < NUM_SHADOW_CASCADES; ++i) {
        float shadow_size = shadow_sizes[i];
        float shadow_radius = shadow_size / 1.414213563731f / 2.0f;  // Get radius of circle inscribed in square with sides 'shadow_size'
        vec3 shadow_center = camera_pos;
        vec3 light_space_center(
            dot(shadow_center, basis[0]),
            dot(shadow_center, basis[1]),
            dot(shadow_center, basis[2]));
        // Snap center to nearest texel to improve frame-to-frame coherency
        float texel_size = shadow_size * 2.0f / graphics->shadow_res;
        for (int j = 0; j < 3; ++j) {
            light_space_center[j] = floor(light_space_center[j] / texel_size) * texel_size;
        }
        // Update shadow center to new texel-snapped position
        shadow_center = light_space_center[0] * basis[0] +
                        light_space_center[1] * basis[1];

        GLuint res = graphics->cascade_shadow_res / 2;
        uvec4& viewport = shadow_params.viewport[i];
        switch (i) {
            case 0:
                viewport = uvec4(0, 0, res, res);
                break;
            case 1:
                viewport = uvec4(res, 0, res * 2, res);
                break;
            case 2:
                viewport = uvec4(0, res, res, res * 2);
                break;
            case 3:
                viewport = uvec4(res, res, res * 2, res * 2);
                break;
        }
        mat4 proj, view;
        camera->applyShadowViewpoint(light_dir, shadow_center, shadow_size, &proj, &view);
        mat4 proj_view_matrix = proj * view;
        graphics->cascade_shadow_mat[i] = proj_view_matrix;
        shadow_params.proj_view_matrix[i] = proj_view_matrix;
        for (int j = 0; j < 6; ++j) {